RARE DISEASE
Hemolytic disease due to fetomaternal alloimmunization
Hemolytic disease due to fetomaternal alloimmunization
Hemolytic disease due to fetomaternal alloimmunization
Synonyms: HDFN, Hemolytic disease of the fetus and newborn
Synonyms: HDFN, Hemolytic disease of the fetus and newborn
Synonyms: HDFN, Hemolytic disease of the fetus and newborn
Drug discovery
3
drugs
With orphan designations
Overview
Hemolytic disease due to fetomaternal alloimmunization occurs when maternal IgG antibodies target fetal red blood cell antigens (typically RhD, Kell, or Duffy), causing hemolysis, anemia, and hyperbilirubinemia. It arises from maternal sensitization via prior pregnancy, transfusion, or fetomaternal hemorrhage. Severe cases may lead to hydrops fetalis or kernicterus, but RhD immunoprophylaxis has significantly reduced incidence [1][4][8].
Burden
Perinatal mortality has declined from 50% to <5% with IUT and immunoprophylaxis [4][8].
Up to 30% of neonates require postnatal transfusions for anemia, with hydrops fetalis linked to 61% survival versus 96% in non-hydropic cases [2][12].
Non-RhD alloimmunization is rising proportionally, contributing to residual morbidity despite RhD prevention [6][9].
Therapies
Antenatal: Intrauterine transfusion (IUT) for fetal anemia detected via middle cerebral artery Doppler velocimetry [2][10], with 90% survival in non-hydropic fetuses [2].
Postnatal: Phototherapy, exchange transfusion, and IV immunoglobulin for hyperbilirubinemia; late anemia often requires transfusions [4][8][12].
Prevention: Anti-D immunoglobulin for RhD-negative mothers, but no prophylaxis exists for non-RhD antigens [3][5][9].
Categories: rare hematological diseases
Research Papers
726 drug discovery papers about Hemolytic disease due to fetomaternal alloimmunization, with 2 first-in-class and 10 next-in-class emerging drug candidates forecasted to outperform the average preclinical success rate. Recent publications:
726 drug discovery papers about Hemolytic disease due to fetomaternal alloimmunization, with 2 first-in-class and 10 next-in-class emerging drug candidates forecasted to outperform the average preclinical success rate. Recent publications:
categories:
Small molecules
small molecules
2026-07-20 | The V3 Phase Architecture Applied to the Entire Human Humoral Immune System: A Complete, Certifiable Ada/SPARK Framework Simulating the Assembly of All Four Immunoglobulin Isotypes (IgM, IgG, IgA, IgE) with Pathological Stress Testing Across 10 Immunological Diseases — Validated by Inverse Invariant Collapse and GNATprove 100%
s ABSTRACT: Background & Biological Hypothesis: Classical immunology often views humoral immunodeficiencies, autoimmune disorders, and hypersensitivity reactions as isolated biochemical anomalies governed by complex molecular cascades. This study provides formal proof for a novel biophysical paradigm: human humoral immunity functions as a unified phase-equilibrium system governed by deterministic biophysical invariants (V3 energy invariant Ψ_V3 = 48,016.8 kg/m² and critical bioelectric potential Φ_critical = -51.1 mV). Within this framework, biological health is defined as structural phase stability, whereas immune pathologies represent predictable, threshold-driven phase ruptures. Biological Proof & Mechanistic Discovery: Through high-integrity computational modeling of all four major immunoglobulin classes (IgM, IgG, IgA, IgE), we demonstrate that specific immunopathologies do not occur randomly, but are triggered precisely when individual biophysical parameters cross non-negotiable physical thresholds: • IgM & Assembly Topology: Pentameric IgM integrity requires strict k = 7 heptadic closure via the J-chain. We prove that a drop below k = 5 prevents ring closure, dumping truncated monomers into the bloodstream and causing Waldenström macroglobulinemia. Furthermore, an bioelectric potential shift above Φ > -40.0 mV disrupts polypeptide folding energy, triggering Selective IgM Deficiency, while loss of vesicular transport coherence (< 50%) leads to Hyper-IgM Syndrome. • IgG & Structural Flexibility: Proper H2L2 domain folding coherence is required for secretable IgG; falling below 60% coherence triggers endo-reticular degradation, causing Hypogammaglobulinemia. Hinge region destabilization below 70% impairs receptor binding dynamics, causing Myasthenia Gravis, while endosomal pH-FcRn gradient disruption halts maternal-fetal transfer, driving Hemolytic Disease of the Fetus and Newborn (HDFN). • IgA & Mucosal Shielding: Mucosal protection strictly depends on the presence of the Secretory Component (SC); its absence completely strips mucosal immunity, resulting in Selective IgA Deficiency. Additionally, hinge O-glycosylation below an 80% threshold alters protein solubility, proving that IgA Nephropathy (Berger’s Disease) is driven by threshold-dependent glomerular self-aggregation. • IgE & Allergic Signaling: IgE over-coherence (> 90%) drives unchecked production seen in Hyper-IgE (Job's) Syndrome. Conversely, when allergen-mediated FcεRI crosslinking density exceeds 30%, the mast-cell membrane equilibrium collapses instantly, releasing massive histamine surges in Anaphylactic Shock. Significance for Immunology: This work formally proves that immunological diseases are quantifiable physical phase ruptures. By mapping ten distinct clinical conditions to exact mathematical thresholds, the V3 framework demonstrates that humoral pathologies share a single universal law of phase rupture. This transforms clinical immunology from a descriptive science into a predictive, deterministic biophysical discipline, offering a new foundation for therapeutic target design and precision immunotherapeutics.
2026-04-20 | Defect-Related Photoluminescence in Hydroxyapatite Nanoparticles Modulated by Carbonate Incorporation.
The investigation of defect-related photoluminescence in hydroxyapatite (HA) nanoparticles (NPs) is essential for understanding their electronic structure and charge carrier recombination dynamics. These insights are important to advancing HA-based materials in photocatalysis, optical devices, hard tissue spectroscopy, and cellular bioimaging. In this study, we provide new evidence on the structural and compositional factors that govern the intrinsic photoluminescence of HA NPs synthesized by chemical precipitation at room temperature, and subjected to thermal treatment at 400 and 450 °C. Carbonate contents ranging from 0.6 to 10.9 wt % were introduced into HA nanorods during synthesis through AB-type substitution, replacing both OH- (A-type) and PO4 3- (B-type) groups. Increasing carbonate incorporation led to enhanced emissions under 405 nm excitation, with a primary band centered at 438 nm. Subsequent thermal treatment further amplified the emission intensity, with the strongest luminescence observed in samples containing higher carbonate content, which also exhibited a red-shift of the emission maximum to approximately 583 nm. These changes were mainly attributed to the progressive increase in carbonate concentration, particularly through B-type substitution, which promotes structural disorder, reduces crystallite size, and generates higher densities of vacancies defects, including VCa, VOH, and VO in PO4 3- groups, as well as to the elimination of structural water during heating. These results confirm that carbonate, a frequent impurity in almost all HA NPs obtained by wet methods without strict experimental conditions (e.g., inert atmosphere), plays a central role in modulating the density of defects and, consequently, the photoluminescence properties in both as-synthesized and thermally treated forms. We also demonstrate the use of citrate-functionalized carbonated HA NPs for cellular bioimaging with HDFn cells as a model, underscoring their potential for biomedical applications.
2025-12-12 | The Effects of Prednisone and Aspirin Administration on Pregnancy Outcomes in Mothers with RhD Isoimmunization and a History of Recurrent Pregnancy Loss: A Case Report
Introduction: Rhesus incompatibility arises when an Rh-negative mother becomes sensitized to the D antigen of an Rh-positive fetus, triggering the production of anti-D antibodies, a process known as isoimmunization. This condition is associated with severe obstetric complications, including Recurrent Pregnancy Loss (RPL) and Hemolytic Disease of the Fetus and Newborn (HDFN). Clinical management remains challenging, as no single therapeutic modality can comprehensively eliminate the adverse effects of isoimmunization. A targeted and integrated management approach is therefore imperative to optimize pregnancy outcomes. Emerging evidence suggests that corticosteroids combined with aspirin may confer beneficial effects in patients with rhesus incompatibility. Case Presentation: A 27-year-old woman, G5P0A4, with RhD-negative status, experienced recurrent pregnancy loss and was managed with prednisone (10 mg/day), aspirin, and Rh immunoglobulin (RhIg) at appropriate gestational intervals. The patient successfully carried the pregnancy to 36 weeks and six days, resulting in the birth of a healthy neonate. Discussion: Rhesus incompatibility is a clinically significant condition in which Rh-negative mothers develop isoimmunization following exposure to Rh-positive fetal blood, producing antibodies against fetal red blood cell antigens. This immunological response contributes to adverse pregnancy outcomes, most notably RPL and HDFN, both carrying substantial maternal and neonatal morbidity. Effective management continues to pose considerable clinical challenges due to limited therapeutic interventions capable of mitigating the immunological consequences of isoimmunization. Evidence from published case reports indicates that combined prednisone and aspirin administration may represent a promising adjunctive therapeutic strategy alongside RhIg prophylaxis. Conclusion: The integrated management incorporating RhIg prophylaxis as the cornerstone of therapy alongside adjunctive prednisone and aspirin was associated with a successful pregnancy outcome in this RhD-negative mother with a history of RPL. The relative contribution of each therapeutic component cannot be determined from a single case report. Further prospective studies with larger sample sizes are needed to evaluate the independent efficacy of corticosteroids and aspirin in this clinical context.
2025-01-09 | How I use noninvasive prenatal testing for red blood cell and platelet antigens.
Alloimmunization during pregnancy occurs when a mother produces antibodies against fetal antigens, leading to complications like hemolytic disease of the fetus and newborn (HDFN) and fetal and neonatal alloimmune thrombocytopenia (FNAIT). HDFN involves destruction of fetal red blood cells, potentially causing severe anemia, hydrops fetalis, and fetal death. FNAIT affects fetal platelets and possibly endothelial cells, resulting in risk of intracranial hemorrhage and brain damage. Traditional invasive methods for fetal antigen genotyping, like amniocentesis, carried miscarriage risks. The discovery of cell-free fetal DNA (cff-DNA) in maternal plasma enabled safe, noninvasive prenatal testing (NIPT). Initially used for Rhesus antigen D blood group typing, NIPT now covers various blood group antigens. Advances in technology have further enhanced the accuracy of NIPT. Despite challenges such as low cff-DNA fractions and complex genetic variations, NIPT has become essential in managing alloimmunized pregnancies. In NIPT it is important to prevent both false-positive results and false-negative results. Particularly in the coming decades, more possibilities for personalized antenatal treatment for HDFN and FNAIT cases will become apparent and accurate NIPT blood group antigen typing results are crucial for guiding clinical decisions. In this paper we describe this journey and provide practical tools for the clinic.
2024-04-29 | Transfusion management and hemoglobin-based oxygen carrier treatment in a patient with anti-Rh17 antibody.
Abstract Background A 54‐year‐old Hispanic OPos female with known history of anti‐Rh17 antibodies was diagnosed with Philadelphia‐Chromosome positive (Ph+) acute lymphoblastic leukemia (ALL). Rh17, also known as Hr 0 , is a high‐frequency antigen composed of several epitopes on the RhCE protein. Anti‐Rh17 antibodies can be made by individuals with missing or varied C/c, E/e antigens. Anti‐Rh17 antibodies are clinically significant given multiple case reports of hemolytic disease of the fetus and newborn (HDFN). Finding compatible units for patients with anti‐Rh17 can be particularly difficult given that only 1 in 100,000 people are Rh17 negative. Study Design and Methods Search for compatible units was conducted by the American Rare Donor Program (ARDP) with no leads. After chemotherapy induction and despite erythropoiesis stimulating agent administration, the patient's hemoglobin continued to trend down to a nadir of 2.8 g/dL. Here we report transfusion of incompatible pRBC to this patient with critically symptomatic anemia. HBOC‐201 (Hemopure) was obtained and administered under an emergency compassionate/expanded access designation from the Food and Drug Administration (FDA) under an emergency Investigational New Drug (IND) application. Results and Discussion Overall difficulties in this case included the challenge of finding compatible units, dilemma of transfusing incompatible units in a patient with severe anemia and obtaining alternatives to blood products. This case report demonstrates the successful use of HBOC‐21 in treating life‐threatening anemia.
cell therapies
2026-04-13 | Routine transfusion of Rh(D)-positive RBCs to Rh(D)-negative patients designated as do not resuscitate conserves Rh(D)-negative red blood cell inventory.
A minority of blood donors are Rh(D)-negative, and Rh(D)-negative red blood cell (RBC) products are often overutilized. As such, Rh(D)-negative RBCs may be difficult to maintain in blood bank inventory. We changed our blood bank laboratory policy to approve non-alloimmunized Rh(D)-negative patients to receive Rh(D)-positive RBCs for routine transfusion under defined criteria. Those criteria included Rh(D)-negative males (all ages) and females (aged >50 years) who were designated as do not resuscitate (DNR), either with or without intubation, in the electronic medical record. From August 15, 2024 through August 15, 2025, a total of 204 Rh(D)-negative patients met the above criteria and were approved to receive routine Rh(D)-positive RBC transfusions. Within that group, 23 patients received Rh(D)-positive RBCs. The remaining patients either did not require transfusion or were issued Rh(D)-negative RBC units. Since implementing this practice, a total of 68 Rh(D)-negative units were conserved during this time frame. Notably, 28 of the 68 units (41%) were type O, Rh(D)-negative. Rh(D)-positive RBCs can be routinely given to non-alloimmunized Rh(D)-negative patients who are not at risk for developing hemolytic disease of the fetus and newborn (HDFN). By creating clear guidelines for the routine administration of Rh(D)-positive RBCs to patients who are not at risk for HDFN, the inventory of Rh(D)-negative RBC units can be directed to those patients who would most benefit from this limited resource.
2026-04-08 | Clinical Characteristics of Early-Onset Severe Hemolytic Disease of the Fetus and Newborn and Treatment Efficacy of Serial Intrauterine Transfusions: A 10-Year Single-Center Experience in China
Abstract Objective: To summarize the clinical characteristics of early-onset severe hemolytic disease of the fetus and newborn (HDFN) in a Chinese cohort and identify factors influencing intrauterine transfusion (IUT) frequency and pregnancy outcomes. Methods: This retrospective cohort study included cases managed between 2013 and 2022. Factors affecting IUT efficacy were analyzed with regard to subsequent IUT risk and adverse pregnancy outcomes. Survival analysis for recurrent events was performed to assess subsequent IUT risk. Results: Of the 97 cases included, 38 were identified as early-onset severe HDFN. Compared with non-early-onset severe HDFN, early-onset severe HDFN was characterized by higher anti-D titer (1:1024 vs . 1:512, respectively, P = 0.006), multiple alloantibodies (50.00% vs . 20.34%, respectively, P = 0.002), and an earlier gestational age at initial IUT (22.4 ± 3.2 vs . 29.0 ± 3.5 weeks, respectively, P < 0.001). In addition, early-onset severe HDFN correlated with increased IUT frequency (hazard ratio ( HR ): 2.01, 95% confidence interval ( CI ): 1.26–3.20, P = 0.003). Factors prolonging IUT intervals included transfused volume ( HR : 0.99, 95% CI : 0.97–0.99; P < 0.001), hematocrit after IUT ( HR : 0.96, 95% CI : 0.95–0.98; P < 0.001), and immunotherapy ( HR : 0.59, 95% CI : 0.38–0.93; P = 0.024). Conclusion: The characteristics of early-onset severe HDFN in Chinese patients are different from those observed in western cohorts. These patients frequently present with higher anti-D titers and a more complex spectrum of multiple alloantibodies. The occurrence of early-onset severe HDFN is associated with an increased frequency of IUT and lower live birth rates. Therefore, exploring effective interventions to delay the first IUT is critical to optimizing the timing and efficacy of intrauterine management for these high-risk cases.
2026-02-16 | Cost-effectiveness of cEK-preventive matched transfusion strategies for female transfusion recipients to prevent haemolytic disease of the foetus and newborn in the Dutch healthcare setting.
Haemolytic disease of the foetus and newborn (HDFN) is a potentially severe condition caused by maternal alloimmunization against foetal red blood cell (RBC) antigens. In the Netherlands, female transfusion recipients under 45 years currently receive RBCs matched for c, D, E and K antigens (D and cEK-matching) to prevent alloantibody formation. We evaluated the cost versus utility of cEK-matching strategies to optimize the prevention of HDFN. Four strategies for females under 45 years of age were compared: current cEK-matching, cK-matching, K-matching and no antigen matching. The model used recent Dutch data on alloimmunization incidence and incorporated lifetime costs and quality-adjusted life years (QALYs). Sensitivity analyses were conducted to assess robustness across different assumptions. Compared to the current cEK-matching strategy, cK-matching reduced lifetime costs by €79,000 per yearly cohort of 177,248 pregnant women, with a minor QALY loss of 0.02. Matching for K only and no matching were both associated with higher costs and greater QALY losses. Across all plausible willingness-to-pay (WTP) thresholds, cK-matching had the highest probability of being cost effective. Transfusion matching for c and K, but not E, is the most cost-effective strategy to prevent HDFN in the Dutch setting. Matching for E provides minimal health benefit at higher costs. These findings support revising current guidelines to cK-matching, ensuring optimal prevention of HDFN while reducing healthcare expenditures.
2026-01-09 | The second reported case of a hemolytic transfusion reaction caused by anti-Sc2: a clinical diagnosis.
SC2 is a low-prevalence antigen of the Scianna blood group system, historically associated with hemolytic disease of the fetus and newborn and only one prior case of hemolytic transfusion reaction (HTR). We report a second case of anti-Sc2-mediated HTR in a 33-year-old woman with β-thalassemia major and a history of anti-Sc2. She presented for routine transfusion and received 1 group O, D-E-K-S-Jk(a-) red blood cell (RBC) unit that was crossmatch compatible by the antihuman globulin (AHG)-polyethylene glycol testing method. Shortly after the transfusion, she developed chills and back pain that resolved with meperidine. Several hours later, she experienced jaundice, dark urine, and fatigue. Laboratory evaluation revealed a hemoglobin drop below the pre-transfusion baseline, elevated bilirubin (8.0 mg/dL, reference range ≤1.2 mg/dL), and a 2+ incompatibility between the post-transfusion sample and the donor RBC unit segment. Although the direct antiglobulin test and the antibody screen remained negative, reference testing confirmed anti-Sc2 in the post-transfusion plasma, and the donor RBC unit was Sc2+. This case reinforces the clinical relevance of anti-Sc2, highlights limitations of conventional antibody screening and the AHG crossmatch in detecting low-prevalence antigens, and supports the need for heightened clinical suspicion and individualized transfusion strategies, including additional targeted pre-transf usion testing, early consultation with reference laboratories, and sourcing of antigen-negative units in patients with known rare alloantibodies.
2025-11-26 | Intrauterine transfusion: Best practices, techniques, and evolving trends.
Intrauterine transfusion (IUT) remains the cornerstone of treatment for severe fetal anemia, particularly due to red blood cell alloimmunization, and is increasingly utilized in select non-immune conditions such as complicated monochorionic twins and parvovirus B19 infection. This narrative review provides a comprehensive overview of current best practices and recent developments in IUT therapy, including indications, diagnostic strategies, procedural techniques, outcomes, and emerging trends. Evidence-based guidelines, multicenter cohort studies, and expert consensus statements were reviewed, with particular attention to diagnosis and management of fetal anemia, procedural safety, timing, transfusion strategy, and center-level practices. The introduction of ultrasound-guided intravascular transfusion via the intrahepatic vein or placental cord insertion has markedly reduced procedure-related risks, resulting in survival rates exceeding 85 % in most settings and favorable long-term outcomes. Despite these advances, challenges persist for early gestational interventions and recurrent transfusions. Overall, IUT is a highly effective intervention for fetal anemia when performed in specialized centers with multidisciplinary expertise.
antibodies
2026-07-21 | Role of Antenatal IVIG in Improving Fetal Outcomes in Rh Isoimmunised Pregnancies: A Single Centre Analysis.
Rh isoimmunisation remains a major cause of hemolytic disease of the fetus and newborn, particularly when fetal anaemia develops early in gestation. Antenatal intravenous immunoglobulin (IVIG) has been proposed to improve fetal outcomes, but evidence remains limited, especially from low- and middle-income settings. This study was conducted at a tertiary care centre in India and included pregnant women with severe anti-D isoimmunisation managed between 2023 to 2025. Inclusion criteria was pregnant women, with a previous pregnancy complicated by hydrops with perinatal death and/or requirement of intrauterine transfusion (IUT) before 24 weeks. They received antenatal IVIG (1 g/Kg/week from 13-14 weeks for 4-6 doses) and were compared with cases managed without IVIG. Outcomes analysed included presence of fetal hydrops, the requirement for IUT and the total number of IUTs, gestational age at first IUT, gestational age at delivery, and pregnancy outcome (live birth, stillbirth, or abortion) and neonatal outcomes. Thirty four pregnancies were included with17 managed with IVIG and 17 managed without IVIG based on the timing of referral. The incidence of fetal hydrops was significantly lower in the IVIG group [5.9% vs 52.9%, p = 0.008], and preterm delivery occurred less frequently [70.5% vs 100%, p = 0.04]. The need for IUT, gestational age at first IUT, number of IUTs, gestational age at delivery, and birth weight were comparable between groups. Live birth rate and survival at discharge were higher in the IVIG group, though differences did not reach statistical significance. Infusion-related reactions occurred in 17.6% of IVIG-treated patients and were mild. Antenatal IVIG was associated with reduced fetal hydrops and preterm delivery in severe Rh isoimmunised pregnancies. However, these findings should be interpreted with caution, as improved outcomes may also reflect earlier referral, surveillance, and intervention.
2026-07-01 | Characterization of the clinical course of early‐onset severe hemolytic disease of the fetus and newborn
Abstract Introduction Severe fetal anemia developing at ≤24 weeks gestational age (GA) in pregnancies complicated by early‐onset severe hemolytic disease of the fetus and newborn (EOS‐HDFN) is managed by intrauterine erythrocyte transfusions (IUTs). Evidence of off‐label intravenous immunoglobulin (IVIG) for preventing/reducing fetal hydrops, fetal anemia, and IUT(s) remains limited to retrospective studies and case series. The prospective, global, multicenter, observational CLARITY study characterized standard‐of‐care management and outcomes for high‐risk pregnancies complicated by EOS‐HDFN and their offspring at expert referral centers. Methods CLARITY enrolled individuals with singleton pregnancies at ≥8 weeks GA and high risk for EOS‐HDFN, defined by prior severe fetal anemia, fetal hydrops, or stillbirth at ≤24 weeks GA with indicative fetal/placental HDFN pathology, and current titers ≥32 anti‐Rhesus D (RhD) or ≥4 anti‐Kell with a confirmed antigen‐positive fetus. Results Of 15 pregnant participants, two (13%) achieved the primary endpoint of a live birth at ≥32 weeks GA without IUT, indicating the absence of clinically relevant fetal anemia and low disease burden. Fourteen (93%) pregnancies resulted in a live birth (median GA, 36 2/7 weeks; range, 31 4/7 –38 0/7 ), including seven (50%) preterm births and 12 (86%) cesarean deliveries. Thirteen (87%) participants required IUTs (median IUTs/pregnancy, 4; range, 1–11), with median GA at first IUT of 24 0/7 weeks (range, 13 0/7 –28 2/7 ). One (7%) fetal death occurred at 16 5/7 weeks, following early IUT (13 0/7 weeks) and serial IVIG treatment (13 1/7 –14 6/7 weeks). IUT complications occurred in four (31%) pregnant participants who received IUTs. In an exploratory, post hoc analysis, eight (53%) pregnant participants received IVIG starting between 10 6⁄7 and 19 3⁄7 weeks (median administrations/pregnancy, 12.5; range, 1–20); IVIG‐related complications were reported in three (38%), and two (25%) met the primary endpoint. Of 14 live‐born neonates followed through 12 weeks of life, three (21%) received exchange transfusion(s), nine (64%) received simple transfusion(s) (one required both types of transfusions), while three (21%) required no transfusions (one required no IUTs during the pregnancy). Conclusion Outcomes of this prospective study of high‐risk EOS‐HDFN pregnant participants and their offspring are consistent with previous retrospective studies, indicating a high risk of early IUT, neonatal transfusions, and fetal/neonatal morbidity and mortality. The results underscore the unmet medical need for effective treatments for EOS‐HDFN. Trial registration ClinicalTrials.gov Identifier: NCT03755128.
2026-06-19 | What is the latest evidence for anti-D immunoglobulin in reducing the risk of haemolytic disease of the fetus and newborn?
Anti-D immunoglobulin is effective in preventing Rh alloimmunization and reducing the risk of hemolytic disease of the fetus and newborn, with evidence supporting both antenatal and postpartum administration.
2026-04-24 | Adverse perinatal outcomes indicative of RhD-mediated hemolytic disease of the fetus and newborn in Eastern Ethiopia: evidence of maternal health inequity in a multicenter cohort study.
Although hemolytic disease of the fetus and newborn (HDFN) has become rare in high-income countries, it remains a significant cause of perinatal death in low-and middle-income countries. Nonetheless, true epidemiological data in Africa are lacking. To obtain insight into the prevalence of anti-Rhesus D-mediated HDFN in Ethiopia, pregnancy outcomes were compared between RhD-negative and RhD-positive women. A multicenter facility-based retrospective cohort study was performed on 6796 women who gave birth (≥28 weeks of gestation) in 13 Ethiopian Obstetric Surveillance System hospitals from January to March 2024. Data were retrospectively collected from maternal and neonatal medical records from antenatal care to birth and neonatal registry. The composite adverse perinatal outcomes (APO) included stillbirth, neonatal loss, or Neonatal Intensive Care Unit admission. The likelihood of HDFN was based on clinical review by 3 experts blinded to the maternal blood group. In 6141 of 6796 women with known RhD status, 327 (5.3%) were RhD-negative. APO was seen in 13.3% women, and occurred twice as often in RhD-negative, as compared to RhD-positive women (aOR=2.3; 95% CI: 1.7-2.9). Clinical signs were highly suggestive of HDFN in 5.8% of RhD-negative women, as compared to 0.2% in RhD-positive women (P<.0001). Our study identifies that RhD-negative women experience a two-fold increased odds of APO, most likely due to HDFN. This highlights the need for strategies to address these maternal and child health inequities, including using anti-RhD immunoprophylaxis to prevent HDFN and screening for blood group antibodies to identify pregnancies at risk.
2026-04-08 | Understanding the consequences of being RhD immunized during pregnancy 10 years after introduction of targeted routine antenatal anti-D prophylaxis: A retrospective nationwide cohort study.
Targeted routine antenatal anti-D prophylaxis (RAADP) was introduced in Finland in 2014. The aim of this study was to assess the prevalence of anti-D immunizations among pregnant women and the severity of hemolytic disease of the fetus and newborn (HDFN) in affected pregnancies 10 years after RAADP was added to the national prevention program in the context of a rapidly declining birthrate in Finland. A nationwide, retrospective cohort study included all RhD-negative pregnancies in Finland between 2014 and 2023. Information on antenatal screening was obtained from the Finnish Red Cross Blood Service database, and obstetric and neonatal data from hospitals' records. Primary outcomes were prevalence of anti-D immunization and severity of HDFN defined as severe (intrauterine transfusion, IUT), moderate (neonatal exchange transfusion/intravenous immunoglobulin, IVIG/top-up transfusion), and mild (phototherapy). The secondary outcome was the effect of declining birth rates on the absolute numbers of anti-D pregnancies. The study included a total of 518 pregnancies of 383 women with anti-D (367 pregnancies with RhD-positive fetus/neonate). In 10 years, the prevalence of anti-D among RhD-negative pregnant women declined from 1.33% to 0.48% (reduction of 64%), and of severe HDFN from 0.20% to 0.06% (reduction of 72%). For an RhD-positive fetus, the risk of severe HDFN was 17.7% (95% CI 13.9% to 22.0%), with an overall survival rate of 90.8%. For a RhD-positive neonate not treated with IUTs, the risks of moderate and mild HDFN were each 33.0% (95% CI 24.4% to 42.6%). In addition to the effect of RAADP, the actual number of anti-D cases decreased by 34.0% due to the 24% fall in the birth rate during the study period. Ten years after the introduction of targeted RAADP, the prevalence of anti-D immunizations was reduced by more than half. Declining birth rates further reduce overall case numbers but do not lessen the complexity of care needed. A significant proportion of anti-D pregnancies still require close monitoring or intervention. Optimizing screening strategies, referral pathways, and readiness for neonatal treatment remains essential in the evolving landscape of HDFN prevention and management.
proteins
2025-10-31 | Successful management of severe hemolytic disease of the fetus and newborn (HDFN) due to anti-Kell.
Hemolytic disease of the fetus and newborn (HDFN) is a potentially life-threatening condition, caused by maternal alloimmune antibodies targeting fetal red blood cells. This report aims to present a case of severe early-onset anti-K-mediated HDFN, managed successfully with intravenous immunoglobulin (IVIG), therapeutic plasma exchange (TPE) and intrauterine transfusion (IUT), and to discuss comparable alternative approaches reported in the literature. We treated a 32-year old woman in her third pregnancy with a high titer of anti-K alloantibodies (1:2048), detected in the first trimester. Weekly IVIG therapy of 1 g/kg was initiated at 15 weeks of gestation, followed by four TPEs and two IUTs. Due to suspected fetal anemia at 33 weeks of gestation, we opted for delivery. The newborn required phototherapy and erythropoietin treatment, with normal development at age two. To contextualize our approach, we reviewed published cases of anti-K-mediated HDFN and compiled a comparative table of treatment strategies and outcomes. Analysis showed that treatment protocols varied in IVIG dosing, TPE use, and timing, reflecting the absence of standardized approaches. These strategies were associated with delayed IUT and improved neonatal outcomes following prior fetal losses. Our case, along with the review of published cases, supports the use of IVIG, with or without TPE, in managing anti-K alloimmunized pregnancies. The variability in treatment approaches underscores the need for individualized care based on maternal antibody titers, fetal antigen status, and disease progression, while emphasizing the importance of standardized protocols and prospective studies to guide optimal management.
2025-08-03 | Understanding, detecting, and managing the "late" anemia of hemolytic disease of the fetus and newborn.
The "late" anemia of hemolytic disease of the fetus and newborn (HDFN), first described over 65 years ago, remains incompletely understood and inconsistently treated. We suspect that deficiencies in understanding its pathogenesis and fostering uniformity in its management could be remedied by teams working collaboratively to test the best ideas through multicentered trials. We begin this review by proposing a data-based definition of anemia, and of "severe" anemia, among infants at birth and during the neonatal period. We then review early as well as recent reports of the "late" anemia of HDFN, suggesting that two pathogenic forms of the condition exist; hemolytic vs. non-hemolytic (hypoproductive). We then review the use of a noninvasive and rapid means of differentiating between these two possibilities, in any given case. Next, we review means of either preventing the "late" anemia or treating it without red blood cell transfusions, using erythropoietic stimulating agents (darbepoetin or erythropoietin). We present our preferred method, using darbepoetin, and explain what we see as the chief advantages. We call for the development of transfusion stewardship programs in each NICU, to establish NICU transfusion guidelines, periodically evaluate compliance, and provide advice for problem cases. In addition, these programs can endorse a consistent approach to managing neonates with HDFN, during their NICU stay and for the weeks after discharge. We end the review with a gap analysis and a call for new focused research aimed at producing better outcomes for these patients, and less uncertainty and stress for these families.
2024-05-10 | Evaluation of erythrocyte and reticulocyte indices in a newborn with severe hemolytic disease
Currently, significant progress has been made in the prevention, diagnosis and treatment of hemolytic disease of the fetus and newborn. However, the development of anemia in a newborn child due to this disease remains an urgent problem for both neonatologists and pediatricians. In such children, a comprehensive assessment of the hemogram is of particular importance. The study of erythrocyte and reticulocyte parameters of a general blood test is necessary to determine prognostic criteria for the restoration of hematopoiesis and determine the status of iron deficiency. A clinical observation of a newborn child with the development of anemia due to hemolytic disease of the fetus and newborn is presented (clinical case). A dynamic analysis of reticulocyte parameters (absolute and relative numbers) and reticulocyte fractions was carried out. An increase in reticulocytes (absolute and relative numbers) was established, mainly due to the fraction of immature reticulocytes during the development of anemia in a newborn child. Such indicators as the hemoglobin content in reticulocytes, the average hemoglobin content in an erythrocyte, the average hemoglobin concentration in an erythrocyte in a general blood test in an infant during the neonatal period remained within the reference values. The data obtained made it possible to determine a personalized approach to the treatment of anemia and avoid blood transfusion in this child.
2024-01-04 | Case of Hemolytic Disease of the Fetus and Newborn Treated Without Blood Products.
Hemolytic disease of the fetus and newborn (HDFN) affects 3/100,000 to 80/100,000 patients yearly and can cause severe anemia and hyperbilirubinemia. Recombinant human erythropoietin has been used as an adjunct therapy in patients with HDFN and hypo-regenerative anemia in the setting of receiving intrauterine blood transfusions. This case describes a patient with HDFN, in which the family were Jehovah Witnesses, and blood transfusions were declined. The patient had symptomatic anemia with a hematocrit nadir of 18.6%. The patient was successfully treated with recombinant human erythropoietin, ferrous sulfate, and folic acid, avoiding the need for transfusion.
2023-11-30 | Darbepoetin alfa to reduce transfusion episodes in infants with haemolytic disease of the fetus and newborn who are treated with intrauterine transfusions in the Netherlands: an open-label, single-centre, phase 2, randomised, controlled trial.
Up to 88% of infants with haemolytic disease of the fetus and newborn who are treated with intrauterine transfusions require erythrocyte transfusions after birth. We aimed to investigate the effect of darbepoetin alfa on the prevention of postnatal anaemia in infants with haemolytic disease of the fetus and newborn. We conducted an open-label, single-centre, phase 2 randomised controlled trial to evaluate the effect of darbepoetin alfa on the number of erythrocyte transfusions in infants with haemolytic disease of the fetus and newborn. All infants who were treated with intrauterine transfusion and born at 35 weeks of gestation or later at the Leiden University Medical Center, Leiden, Netherlands, were eligible for inclusion. Included infants were randomised by computer at birth to treatment with 10 μg/kg darbepoetin alfa subcutaneously once a week for 8 weeks or standard care (1:1 allocation, in varying blocks of four and six, with no stratification). Treating physicians and parents were not masked to treatment allocation, but the research team, data manager, and statistician were masked to treatment allocation during the process of data collection. The primary outcome was the number of erythrocyte transfusion episodes per infant from birth up to 3 months of life in the modified intention-to-treat population. This trial is registered with ClinicalTrials.gov (NCT03104426) and has been completed. Between Oct 31, 2017, and April 31, 2022, we recruited 76 infants, of whom 44 (58%) were randomly assigned to a treatment group (20 [45%] were allocated to receive darbepoetin alfa and 24 [55%] were allocated to receive standard care). Follow-up lasted 3 months and one infant dropped out of the trial before commencement of treatment. A significant reduction in erythrocyte transfusion episodes was identified with darbepoetin alfa treatment compared with standard care (median 1·0 [IQR 1·0-2·0] transfusion episodes vs 2·0 [1·3-3·0] transfusion episodes; p=0·0082). No adverse events were reported and no infants died during the study. Darbepoetin alfa reduced the transfusion episodes after intrauterine transfusion treatment for haemolytic disease of the fetus and newborn. Treatment with darbepoetin alfa or other types of erythropoietin should be considered as part of the postnatal treatment of severe haemolytic disease of the fetus and newborn. Sanquin Blood Supply. For the Dutch translation of the abstract see Supplementary Materials section.
other
2026-04-25 | Rare antigen-negative red blood cells from pluripotent stem cells for precision transfusion medicine.
Blood bank identification of antibodies against high-prevalence antigens remains a challenge due to the scarcity of antigen-negative reagent red cells sourced from blood donors. The MAM antigen, encoded by EMP3, is one such antigen associated with red cell alloimmunization and hemolytic disease of the fetus and newborn. We used CRISPR-Cas9 gene editing to generate an EMP3 knockout (EMP3KO) induced pluripotent stem cell (iPSC) line from a type O, Rh null parent line, enabling production of rare MAM-negative red blood cells. Since a prior study suggested that loss of EMP3 may enhance erythroid proliferation, we hypothesized that EMP3KO could both yield a rare reagent cell and potentially improve erythroid expansion to support scalable production. Transcriptomic analysis allowed us to further investigate the effect of EMP3 loss in late erythroblasts. EMP3KO cells differentiated efficiently into erythroid cells, showing >95% CD235/CD71 co-expression and orthochromatic erythroblast morphology. Compared to unedited cells, no proliferative advantage was observed, contrasting with prior non-isogenic cell models. Agglutination assays confirmed complete loss of MAM antigen and demonstrated the diagnostic utility for identifying MAM antibodies. Transcriptomic profiling of EMP3KO erythroblasts revealed expression of key erythroid genes, as well as regulators of proliferation and heme metabolism, was comparable to the parent line. This study demonstrates that iPSC technology combined with gene editing can generate rare antigen-negative RBCs for immunohematology applications. Beyond MAM, this platform offers a strategy to create additional rare RBC phenotypes, advancing precision transfusion medicine and improving antibody identification against high-prevalence antigens.
2026-02-12 | AlphaGenome-enabled analysis of non-coding regulatory variants underlying RHD expression with wet-lab validation.
Systematic identification of functional non-coding regulatory variants remains a major challenge in human genetics. Conventional approaches such as large-scale CRISPR screening and genome-wide association studies (GWAS) are powerful but often prohibitively expensive, time-consuming, and experimentally intensive, limiting their scalability for locus-specific mechanistic studies. Recent advances in artificial intelligence offer the potential to partially replace or substantially augment these approaches by prioritizing regulatory variants with high functional likelihood. The RHD antigen, a major contributor to red blood cell alloimmunization, hemolytic transfusion reactions, and hemolytic disease of the fetus and newborn, serves as an excellent model for this paradigm, since coding variants alone do not fully account for differences in RHD expression. Here, we present an integrated artificial intelligence (AI)-guided and experimental framework to identify and validate functional non-coding regulatory variants governing RHD expression. We first applied AlphaGenome (AG), a deep-learning model released in 2025 for non-coding variant impact prediction, to systematically interrogate the RHD locus. By integrating multi-omics datasets, AG prioritized regulatory regions within the promoter, 5' untranslated region (5'UTR), and intragenic regions. In silico deletion- and Single Nucleotide Polymorphism (SNP)-based perturbation analyses consistently predicted that variants within the promoter and its proximal regions, as well as within intragenic regions, exert strong suppressive effects on RHD expression. To experimentally validate these predictions, we performed CRISPR-mediated base editing in K562 cells at AG-prioritized non-coding SNP sites. Editing of a high-score predicted variant (chr1:25272434 G>A) achieved efficient base conversion and was accompanied by additional nearby edits, all predicted by AG to downregulate RHD expression. In contrast, editing of low-score predicted sites (chr1:25272422 C>T) produced much smaller functional effects. Quantitative polymerase chain reaction (qPCR) analysis of full-length RHD transcripts, together with flow cytometry-based analysis of RHD expression, confirmed strong concordance between AI-based predictions and transcriptional as well as phenotypic outcomes. Taken together, our results demonstrate that the combination of AI-guided regulatory variant prioritization and targeted base editing provides a potentially scalable and cost-effective alternative to traditional CRISPR screening for decoding functional non-coding variants in blood group genes, with direct implications for genomics-based RHD typing and transfusion medicine. To our knowledge, this study also represents the first validation of AlphaGenome predictions at the phenotypic level using wet-lab experiments.
2025-12-02 | Non-invasive foetal RhD genotyping: A strategy for rationalizing anti-D immunoglobulin prophylaxis in RhD-negative pregnant women at the Hospital Italiano de Buenos Aires.
The administration of anti-D immunoglobulin achieved a significant reduction in the mortality of haemolytic disease of the foetus and the newborn due to RhD sensitization. Between 30% and 40% of this group of pregnant women, carriers of an RhD-negative foetus, would unnecessarily receive a high-cost drug, exposing them to the risks of a blood derivative. The aim of the study was to assess the accuracy of non-invasive foetal RhD genotyping at different weeks of pregnancy, to allow it to be used to determine appropriate anti-D administration. In this cross-sectional cohort study of foetal RhD genotyping, determined from cell-free foetal DNA (cffDNA) between weeks 8 and 30 of gestation, 270 samples from RhD-negative pregnant women were examined. Foetal Rh status was determined by multiplex PCR in real time, to detect targeting exons 5, 7, and 10 of the RHD gene and the SRY gene (a Y-chromosome-specific marker used to confirm male foetal sex). The performance diagnostic of the foetal RhD screen test offered a sensitivity of 100% (95% confidence interval [CI]: 98.03%-100%), a specificity of 100% (95% CI: 96.3%-100%) and an accuracy of 100%. The prevalence of RhD-negative newborns in RhD-negative pregnant women was 32.5%. The results of the study reveal that the strategy of combining three RhD exons to determine foetal RhD status is reliable, with 100% accuracy. Prenatal diagnosis showed that 32.5% of newborns were RhD negative. Using this strategy, a decrease in the use of anti-D immunoglobulin is expected.
2024-12-09 | Real-world performance of a clinical droplet digital polymerase chain reaction assay for non-invasive foetal blood group and platelet antigen genotyping of alloimmunized pregnant women with antibodies directed against RhD, RhE, Rhc, RhC, K1, HPA-1a or HPA-5b: A 1-year experience.
To test the performance of a new droplet digital polymerase chain reaction (ddPCR) non-invasive foetal blood group and platelet antigen genotyping assay in the setting of a Dutch reference laboratory for foetal blood group and platelet antigen genotyping. Our population comprised 229 consecutive alloimmunized pregnant women who presented between April 2022 and March 2023 with 250 requests for non-invasive foetal RHD, RHE, RHc, RHC, K1, HPA-1a or HPA-5b blood group and platelet antigen genotyping. Samples were genotyped for blood group and platelet antigen alleles along with methylated RASSF1a (mRASSF1a) and sex-determining region of Y (SRY) and DYS14 as positive foetal controls. Negative blood group and platelet antigen results were issued only when foetal controls were positive; otherwise, such samples were classified as inconclusive. The assay achieved a success rate of 98.4% (246 of 250) because one case was lost to follow-up, one case was solved with quantitative polymerase chain reaction (qPCR) and one case precluded foetal typing due to RHD variant mothers. Only 10 cases needed a second sample and one case a third for a valid final result. We identified 116 maternal-foetal blood group and platelet antigen incompatibilities. Clinical non-invasive foetal blood group and platelet antigen typing of alloimmunized pregnant women via ddPCR is successful and represents an improvement over qPCR because of the addition of a foetal control and because ddPCR circumvents potential interference from maternal cell-free DNA (cfDNA) background for foetal HPA-1 and K1.
2023-05-27 | Gene editing without ex vivo culture evades genotoxicity in human hematopoietic stem cells.
Gene editing the BCL11A erythroid enhancer is a validated approach to fetal hemoglobin (HbF) induction for β-hemoglobinopathy therapy, though heterogeneity in edit allele distribution and HbF response may impact its safety and efficacy. Here we compared combined CRISPR-Cas9 endonuclease editing of the BCL11A +58 and +55 enhancers with leading gene modification approaches under clinical investigation. We found that combined targeting of the BCL11A +58 and +55 enhancers with 3xNLS-SpCas9 and two sgRNAs resulted in superior HbF induction, including in engrafting erythroid cells from sickle cell disease (SCD) patient xenografts, attributable to simultaneous disruption of core half E-box/GATA motifs at both enhancers. We corroborated prior observations that double strand breaks (DSBs) could produce unintended on- target outcomes in hematopoietic stem and progenitor cells (HSPCs) such as long deletions and centromere-distal chromosome fragment loss. We show these unintended outcomes are a byproduct of cellular proliferation stimulated by ex vivo culture. Editing HSPCs without cytokine culture bypassed long deletion and micronuclei formation while preserving efficient on-target editing and engraftment function. These results indicate that nuclease editing of quiescent hematopoietic stem cells (HSCs) limits DSB genotoxicity while maintaining therapeutic potency and encourages efforts for in vivo delivery of nucleases to HSCs.
small molecules
2026-07-20 | The V3 Phase Architecture Applied to the Entire Human Humoral Immune System: A Complete, Certifiable Ada/SPARK Framework Simulating the Assembly of All Four Immunoglobulin Isotypes (IgM, IgG, IgA, IgE) with Pathological Stress Testing Across 10 Immunological Diseases — Validated by Inverse Invariant Collapse and GNATprove 100%
s ABSTRACT: Background & Biological Hypothesis: Classical immunology often views humoral immunodeficiencies, autoimmune disorders, and hypersensitivity reactions as isolated biochemical anomalies governed by complex molecular cascades. This study provides formal proof for a novel biophysical paradigm: human humoral immunity functions as a unified phase-equilibrium system governed by deterministic biophysical invariants (V3 energy invariant Ψ_V3 = 48,016.8 kg/m² and critical bioelectric potential Φ_critical = -51.1 mV). Within this framework, biological health is defined as structural phase stability, whereas immune pathologies represent predictable, threshold-driven phase ruptures. Biological Proof & Mechanistic Discovery: Through high-integrity computational modeling of all four major immunoglobulin classes (IgM, IgG, IgA, IgE), we demonstrate that specific immunopathologies do not occur randomly, but are triggered precisely when individual biophysical parameters cross non-negotiable physical thresholds: • IgM & Assembly Topology: Pentameric IgM integrity requires strict k = 7 heptadic closure via the J-chain. We prove that a drop below k = 5 prevents ring closure, dumping truncated monomers into the bloodstream and causing Waldenström macroglobulinemia. Furthermore, an bioelectric potential shift above Φ > -40.0 mV disrupts polypeptide folding energy, triggering Selective IgM Deficiency, while loss of vesicular transport coherence (< 50%) leads to Hyper-IgM Syndrome. • IgG & Structural Flexibility: Proper H2L2 domain folding coherence is required for secretable IgG; falling below 60% coherence triggers endo-reticular degradation, causing Hypogammaglobulinemia. Hinge region destabilization below 70% impairs receptor binding dynamics, causing Myasthenia Gravis, while endosomal pH-FcRn gradient disruption halts maternal-fetal transfer, driving Hemolytic Disease of the Fetus and Newborn (HDFN). • IgA & Mucosal Shielding: Mucosal protection strictly depends on the presence of the Secretory Component (SC); its absence completely strips mucosal immunity, resulting in Selective IgA Deficiency. Additionally, hinge O-glycosylation below an 80% threshold alters protein solubility, proving that IgA Nephropathy (Berger’s Disease) is driven by threshold-dependent glomerular self-aggregation. • IgE & Allergic Signaling: IgE over-coherence (> 90%) drives unchecked production seen in Hyper-IgE (Job's) Syndrome. Conversely, when allergen-mediated FcεRI crosslinking density exceeds 30%, the mast-cell membrane equilibrium collapses instantly, releasing massive histamine surges in Anaphylactic Shock. Significance for Immunology: This work formally proves that immunological diseases are quantifiable physical phase ruptures. By mapping ten distinct clinical conditions to exact mathematical thresholds, the V3 framework demonstrates that humoral pathologies share a single universal law of phase rupture. This transforms clinical immunology from a descriptive science into a predictive, deterministic biophysical discipline, offering a new foundation for therapeutic target design and precision immunotherapeutics.
2026-04-20 | Defect-Related Photoluminescence in Hydroxyapatite Nanoparticles Modulated by Carbonate Incorporation.
The investigation of defect-related photoluminescence in hydroxyapatite (HA) nanoparticles (NPs) is essential for understanding their electronic structure and charge carrier recombination dynamics. These insights are important to advancing HA-based materials in photocatalysis, optical devices, hard tissue spectroscopy, and cellular bioimaging. In this study, we provide new evidence on the structural and compositional factors that govern the intrinsic photoluminescence of HA NPs synthesized by chemical precipitation at room temperature, and subjected to thermal treatment at 400 and 450 °C. Carbonate contents ranging from 0.6 to 10.9 wt % were introduced into HA nanorods during synthesis through AB-type substitution, replacing both OH- (A-type) and PO4 3- (B-type) groups. Increasing carbonate incorporation led to enhanced emissions under 405 nm excitation, with a primary band centered at 438 nm. Subsequent thermal treatment further amplified the emission intensity, with the strongest luminescence observed in samples containing higher carbonate content, which also exhibited a red-shift of the emission maximum to approximately 583 nm. These changes were mainly attributed to the progressive increase in carbonate concentration, particularly through B-type substitution, which promotes structural disorder, reduces crystallite size, and generates higher densities of vacancies defects, including VCa, VOH, and VO in PO4 3- groups, as well as to the elimination of structural water during heating. These results confirm that carbonate, a frequent impurity in almost all HA NPs obtained by wet methods without strict experimental conditions (e.g., inert atmosphere), plays a central role in modulating the density of defects and, consequently, the photoluminescence properties in both as-synthesized and thermally treated forms. We also demonstrate the use of citrate-functionalized carbonated HA NPs for cellular bioimaging with HDFn cells as a model, underscoring their potential for biomedical applications.
2025-12-12 | The Effects of Prednisone and Aspirin Administration on Pregnancy Outcomes in Mothers with RhD Isoimmunization and a History of Recurrent Pregnancy Loss: A Case Report
Introduction: Rhesus incompatibility arises when an Rh-negative mother becomes sensitized to the D antigen of an Rh-positive fetus, triggering the production of anti-D antibodies, a process known as isoimmunization. This condition is associated with severe obstetric complications, including Recurrent Pregnancy Loss (RPL) and Hemolytic Disease of the Fetus and Newborn (HDFN). Clinical management remains challenging, as no single therapeutic modality can comprehensively eliminate the adverse effects of isoimmunization. A targeted and integrated management approach is therefore imperative to optimize pregnancy outcomes. Emerging evidence suggests that corticosteroids combined with aspirin may confer beneficial effects in patients with rhesus incompatibility. Case Presentation: A 27-year-old woman, G5P0A4, with RhD-negative status, experienced recurrent pregnancy loss and was managed with prednisone (10 mg/day), aspirin, and Rh immunoglobulin (RhIg) at appropriate gestational intervals. The patient successfully carried the pregnancy to 36 weeks and six days, resulting in the birth of a healthy neonate. Discussion: Rhesus incompatibility is a clinically significant condition in which Rh-negative mothers develop isoimmunization following exposure to Rh-positive fetal blood, producing antibodies against fetal red blood cell antigens. This immunological response contributes to adverse pregnancy outcomes, most notably RPL and HDFN, both carrying substantial maternal and neonatal morbidity. Effective management continues to pose considerable clinical challenges due to limited therapeutic interventions capable of mitigating the immunological consequences of isoimmunization. Evidence from published case reports indicates that combined prednisone and aspirin administration may represent a promising adjunctive therapeutic strategy alongside RhIg prophylaxis. Conclusion: The integrated management incorporating RhIg prophylaxis as the cornerstone of therapy alongside adjunctive prednisone and aspirin was associated with a successful pregnancy outcome in this RhD-negative mother with a history of RPL. The relative contribution of each therapeutic component cannot be determined from a single case report. Further prospective studies with larger sample sizes are needed to evaluate the independent efficacy of corticosteroids and aspirin in this clinical context.
2025-01-09 | How I use noninvasive prenatal testing for red blood cell and platelet antigens.
Alloimmunization during pregnancy occurs when a mother produces antibodies against fetal antigens, leading to complications like hemolytic disease of the fetus and newborn (HDFN) and fetal and neonatal alloimmune thrombocytopenia (FNAIT). HDFN involves destruction of fetal red blood cells, potentially causing severe anemia, hydrops fetalis, and fetal death. FNAIT affects fetal platelets and possibly endothelial cells, resulting in risk of intracranial hemorrhage and brain damage. Traditional invasive methods for fetal antigen genotyping, like amniocentesis, carried miscarriage risks. The discovery of cell-free fetal DNA (cff-DNA) in maternal plasma enabled safe, noninvasive prenatal testing (NIPT). Initially used for Rhesus antigen D blood group typing, NIPT now covers various blood group antigens. Advances in technology have further enhanced the accuracy of NIPT. Despite challenges such as low cff-DNA fractions and complex genetic variations, NIPT has become essential in managing alloimmunized pregnancies. In NIPT it is important to prevent both false-positive results and false-negative results. Particularly in the coming decades, more possibilities for personalized antenatal treatment for HDFN and FNAIT cases will become apparent and accurate NIPT blood group antigen typing results are crucial for guiding clinical decisions. In this paper we describe this journey and provide practical tools for the clinic.
2024-04-29 | Transfusion management and hemoglobin-based oxygen carrier treatment in a patient with anti-Rh17 antibody.
Abstract Background A 54‐year‐old Hispanic OPos female with known history of anti‐Rh17 antibodies was diagnosed with Philadelphia‐Chromosome positive (Ph+) acute lymphoblastic leukemia (ALL). Rh17, also known as Hr 0 , is a high‐frequency antigen composed of several epitopes on the RhCE protein. Anti‐Rh17 antibodies can be made by individuals with missing or varied C/c, E/e antigens. Anti‐Rh17 antibodies are clinically significant given multiple case reports of hemolytic disease of the fetus and newborn (HDFN). Finding compatible units for patients with anti‐Rh17 can be particularly difficult given that only 1 in 100,000 people are Rh17 negative. Study Design and Methods Search for compatible units was conducted by the American Rare Donor Program (ARDP) with no leads. After chemotherapy induction and despite erythropoiesis stimulating agent administration, the patient's hemoglobin continued to trend down to a nadir of 2.8 g/dL. Here we report transfusion of incompatible pRBC to this patient with critically symptomatic anemia. HBOC‐201 (Hemopure) was obtained and administered under an emergency compassionate/expanded access designation from the Food and Drug Administration (FDA) under an emergency Investigational New Drug (IND) application. Results and Discussion Overall difficulties in this case included the challenge of finding compatible units, dilemma of transfusing incompatible units in a patient with severe anemia and obtaining alternatives to blood products. This case report demonstrates the successful use of HBOC‐21 in treating life‐threatening anemia.
cell therapies
2026-04-13 | Routine transfusion of Rh(D)-positive RBCs to Rh(D)-negative patients designated as do not resuscitate conserves Rh(D)-negative red blood cell inventory.
A minority of blood donors are Rh(D)-negative, and Rh(D)-negative red blood cell (RBC) products are often overutilized. As such, Rh(D)-negative RBCs may be difficult to maintain in blood bank inventory. We changed our blood bank laboratory policy to approve non-alloimmunized Rh(D)-negative patients to receive Rh(D)-positive RBCs for routine transfusion under defined criteria. Those criteria included Rh(D)-negative males (all ages) and females (aged >50 years) who were designated as do not resuscitate (DNR), either with or without intubation, in the electronic medical record. From August 15, 2024 through August 15, 2025, a total of 204 Rh(D)-negative patients met the above criteria and were approved to receive routine Rh(D)-positive RBC transfusions. Within that group, 23 patients received Rh(D)-positive RBCs. The remaining patients either did not require transfusion or were issued Rh(D)-negative RBC units. Since implementing this practice, a total of 68 Rh(D)-negative units were conserved during this time frame. Notably, 28 of the 68 units (41%) were type O, Rh(D)-negative. Rh(D)-positive RBCs can be routinely given to non-alloimmunized Rh(D)-negative patients who are not at risk for developing hemolytic disease of the fetus and newborn (HDFN). By creating clear guidelines for the routine administration of Rh(D)-positive RBCs to patients who are not at risk for HDFN, the inventory of Rh(D)-negative RBC units can be directed to those patients who would most benefit from this limited resource.
2026-04-08 | Clinical Characteristics of Early-Onset Severe Hemolytic Disease of the Fetus and Newborn and Treatment Efficacy of Serial Intrauterine Transfusions: A 10-Year Single-Center Experience in China
Abstract Objective: To summarize the clinical characteristics of early-onset severe hemolytic disease of the fetus and newborn (HDFN) in a Chinese cohort and identify factors influencing intrauterine transfusion (IUT) frequency and pregnancy outcomes. Methods: This retrospective cohort study included cases managed between 2013 and 2022. Factors affecting IUT efficacy were analyzed with regard to subsequent IUT risk and adverse pregnancy outcomes. Survival analysis for recurrent events was performed to assess subsequent IUT risk. Results: Of the 97 cases included, 38 were identified as early-onset severe HDFN. Compared with non-early-onset severe HDFN, early-onset severe HDFN was characterized by higher anti-D titer (1:1024 vs . 1:512, respectively, P = 0.006), multiple alloantibodies (50.00% vs . 20.34%, respectively, P = 0.002), and an earlier gestational age at initial IUT (22.4 ± 3.2 vs . 29.0 ± 3.5 weeks, respectively, P < 0.001). In addition, early-onset severe HDFN correlated with increased IUT frequency (hazard ratio ( HR ): 2.01, 95% confidence interval ( CI ): 1.26–3.20, P = 0.003). Factors prolonging IUT intervals included transfused volume ( HR : 0.99, 95% CI : 0.97–0.99; P < 0.001), hematocrit after IUT ( HR : 0.96, 95% CI : 0.95–0.98; P < 0.001), and immunotherapy ( HR : 0.59, 95% CI : 0.38–0.93; P = 0.024). Conclusion: The characteristics of early-onset severe HDFN in Chinese patients are different from those observed in western cohorts. These patients frequently present with higher anti-D titers and a more complex spectrum of multiple alloantibodies. The occurrence of early-onset severe HDFN is associated with an increased frequency of IUT and lower live birth rates. Therefore, exploring effective interventions to delay the first IUT is critical to optimizing the timing and efficacy of intrauterine management for these high-risk cases.
2026-02-16 | Cost-effectiveness of cEK-preventive matched transfusion strategies for female transfusion recipients to prevent haemolytic disease of the foetus and newborn in the Dutch healthcare setting.
Haemolytic disease of the foetus and newborn (HDFN) is a potentially severe condition caused by maternal alloimmunization against foetal red blood cell (RBC) antigens. In the Netherlands, female transfusion recipients under 45 years currently receive RBCs matched for c, D, E and K antigens (D and cEK-matching) to prevent alloantibody formation. We evaluated the cost versus utility of cEK-matching strategies to optimize the prevention of HDFN. Four strategies for females under 45 years of age were compared: current cEK-matching, cK-matching, K-matching and no antigen matching. The model used recent Dutch data on alloimmunization incidence and incorporated lifetime costs and quality-adjusted life years (QALYs). Sensitivity analyses were conducted to assess robustness across different assumptions. Compared to the current cEK-matching strategy, cK-matching reduced lifetime costs by €79,000 per yearly cohort of 177,248 pregnant women, with a minor QALY loss of 0.02. Matching for K only and no matching were both associated with higher costs and greater QALY losses. Across all plausible willingness-to-pay (WTP) thresholds, cK-matching had the highest probability of being cost effective. Transfusion matching for c and K, but not E, is the most cost-effective strategy to prevent HDFN in the Dutch setting. Matching for E provides minimal health benefit at higher costs. These findings support revising current guidelines to cK-matching, ensuring optimal prevention of HDFN while reducing healthcare expenditures.
2026-01-09 | The second reported case of a hemolytic transfusion reaction caused by anti-Sc2: a clinical diagnosis.
SC2 is a low-prevalence antigen of the Scianna blood group system, historically associated with hemolytic disease of the fetus and newborn and only one prior case of hemolytic transfusion reaction (HTR). We report a second case of anti-Sc2-mediated HTR in a 33-year-old woman with β-thalassemia major and a history of anti-Sc2. She presented for routine transfusion and received 1 group O, D-E-K-S-Jk(a-) red blood cell (RBC) unit that was crossmatch compatible by the antihuman globulin (AHG)-polyethylene glycol testing method. Shortly after the transfusion, she developed chills and back pain that resolved with meperidine. Several hours later, she experienced jaundice, dark urine, and fatigue. Laboratory evaluation revealed a hemoglobin drop below the pre-transfusion baseline, elevated bilirubin (8.0 mg/dL, reference range ≤1.2 mg/dL), and a 2+ incompatibility between the post-transfusion sample and the donor RBC unit segment. Although the direct antiglobulin test and the antibody screen remained negative, reference testing confirmed anti-Sc2 in the post-transfusion plasma, and the donor RBC unit was Sc2+. This case reinforces the clinical relevance of anti-Sc2, highlights limitations of conventional antibody screening and the AHG crossmatch in detecting low-prevalence antigens, and supports the need for heightened clinical suspicion and individualized transfusion strategies, including additional targeted pre-transf usion testing, early consultation with reference laboratories, and sourcing of antigen-negative units in patients with known rare alloantibodies.
2025-11-26 | Intrauterine transfusion: Best practices, techniques, and evolving trends.
Intrauterine transfusion (IUT) remains the cornerstone of treatment for severe fetal anemia, particularly due to red blood cell alloimmunization, and is increasingly utilized in select non-immune conditions such as complicated monochorionic twins and parvovirus B19 infection. This narrative review provides a comprehensive overview of current best practices and recent developments in IUT therapy, including indications, diagnostic strategies, procedural techniques, outcomes, and emerging trends. Evidence-based guidelines, multicenter cohort studies, and expert consensus statements were reviewed, with particular attention to diagnosis and management of fetal anemia, procedural safety, timing, transfusion strategy, and center-level practices. The introduction of ultrasound-guided intravascular transfusion via the intrahepatic vein or placental cord insertion has markedly reduced procedure-related risks, resulting in survival rates exceeding 85 % in most settings and favorable long-term outcomes. Despite these advances, challenges persist for early gestational interventions and recurrent transfusions. Overall, IUT is a highly effective intervention for fetal anemia when performed in specialized centers with multidisciplinary expertise.
antibodies
2026-07-21 | Role of Antenatal IVIG in Improving Fetal Outcomes in Rh Isoimmunised Pregnancies: A Single Centre Analysis.
Rh isoimmunisation remains a major cause of hemolytic disease of the fetus and newborn, particularly when fetal anaemia develops early in gestation. Antenatal intravenous immunoglobulin (IVIG) has been proposed to improve fetal outcomes, but evidence remains limited, especially from low- and middle-income settings. This study was conducted at a tertiary care centre in India and included pregnant women with severe anti-D isoimmunisation managed between 2023 to 2025. Inclusion criteria was pregnant women, with a previous pregnancy complicated by hydrops with perinatal death and/or requirement of intrauterine transfusion (IUT) before 24 weeks. They received antenatal IVIG (1 g/Kg/week from 13-14 weeks for 4-6 doses) and were compared with cases managed without IVIG. Outcomes analysed included presence of fetal hydrops, the requirement for IUT and the total number of IUTs, gestational age at first IUT, gestational age at delivery, and pregnancy outcome (live birth, stillbirth, or abortion) and neonatal outcomes. Thirty four pregnancies were included with17 managed with IVIG and 17 managed without IVIG based on the timing of referral. The incidence of fetal hydrops was significantly lower in the IVIG group [5.9% vs 52.9%, p = 0.008], and preterm delivery occurred less frequently [70.5% vs 100%, p = 0.04]. The need for IUT, gestational age at first IUT, number of IUTs, gestational age at delivery, and birth weight were comparable between groups. Live birth rate and survival at discharge were higher in the IVIG group, though differences did not reach statistical significance. Infusion-related reactions occurred in 17.6% of IVIG-treated patients and were mild. Antenatal IVIG was associated with reduced fetal hydrops and preterm delivery in severe Rh isoimmunised pregnancies. However, these findings should be interpreted with caution, as improved outcomes may also reflect earlier referral, surveillance, and intervention.
2026-07-01 | Characterization of the clinical course of early‐onset severe hemolytic disease of the fetus and newborn
Abstract Introduction Severe fetal anemia developing at ≤24 weeks gestational age (GA) in pregnancies complicated by early‐onset severe hemolytic disease of the fetus and newborn (EOS‐HDFN) is managed by intrauterine erythrocyte transfusions (IUTs). Evidence of off‐label intravenous immunoglobulin (IVIG) for preventing/reducing fetal hydrops, fetal anemia, and IUT(s) remains limited to retrospective studies and case series. The prospective, global, multicenter, observational CLARITY study characterized standard‐of‐care management and outcomes for high‐risk pregnancies complicated by EOS‐HDFN and their offspring at expert referral centers. Methods CLARITY enrolled individuals with singleton pregnancies at ≥8 weeks GA and high risk for EOS‐HDFN, defined by prior severe fetal anemia, fetal hydrops, or stillbirth at ≤24 weeks GA with indicative fetal/placental HDFN pathology, and current titers ≥32 anti‐Rhesus D (RhD) or ≥4 anti‐Kell with a confirmed antigen‐positive fetus. Results Of 15 pregnant participants, two (13%) achieved the primary endpoint of a live birth at ≥32 weeks GA without IUT, indicating the absence of clinically relevant fetal anemia and low disease burden. Fourteen (93%) pregnancies resulted in a live birth (median GA, 36 2/7 weeks; range, 31 4/7 –38 0/7 ), including seven (50%) preterm births and 12 (86%) cesarean deliveries. Thirteen (87%) participants required IUTs (median IUTs/pregnancy, 4; range, 1–11), with median GA at first IUT of 24 0/7 weeks (range, 13 0/7 –28 2/7 ). One (7%) fetal death occurred at 16 5/7 weeks, following early IUT (13 0/7 weeks) and serial IVIG treatment (13 1/7 –14 6/7 weeks). IUT complications occurred in four (31%) pregnant participants who received IUTs. In an exploratory, post hoc analysis, eight (53%) pregnant participants received IVIG starting between 10 6⁄7 and 19 3⁄7 weeks (median administrations/pregnancy, 12.5; range, 1–20); IVIG‐related complications were reported in three (38%), and two (25%) met the primary endpoint. Of 14 live‐born neonates followed through 12 weeks of life, three (21%) received exchange transfusion(s), nine (64%) received simple transfusion(s) (one required both types of transfusions), while three (21%) required no transfusions (one required no IUTs during the pregnancy). Conclusion Outcomes of this prospective study of high‐risk EOS‐HDFN pregnant participants and their offspring are consistent with previous retrospective studies, indicating a high risk of early IUT, neonatal transfusions, and fetal/neonatal morbidity and mortality. The results underscore the unmet medical need for effective treatments for EOS‐HDFN. Trial registration ClinicalTrials.gov Identifier: NCT03755128.
2026-06-19 | What is the latest evidence for anti-D immunoglobulin in reducing the risk of haemolytic disease of the fetus and newborn?
Anti-D immunoglobulin is effective in preventing Rh alloimmunization and reducing the risk of hemolytic disease of the fetus and newborn, with evidence supporting both antenatal and postpartum administration.
2026-04-24 | Adverse perinatal outcomes indicative of RhD-mediated hemolytic disease of the fetus and newborn in Eastern Ethiopia: evidence of maternal health inequity in a multicenter cohort study.
Although hemolytic disease of the fetus and newborn (HDFN) has become rare in high-income countries, it remains a significant cause of perinatal death in low-and middle-income countries. Nonetheless, true epidemiological data in Africa are lacking. To obtain insight into the prevalence of anti-Rhesus D-mediated HDFN in Ethiopia, pregnancy outcomes were compared between RhD-negative and RhD-positive women. A multicenter facility-based retrospective cohort study was performed on 6796 women who gave birth (≥28 weeks of gestation) in 13 Ethiopian Obstetric Surveillance System hospitals from January to March 2024. Data were retrospectively collected from maternal and neonatal medical records from antenatal care to birth and neonatal registry. The composite adverse perinatal outcomes (APO) included stillbirth, neonatal loss, or Neonatal Intensive Care Unit admission. The likelihood of HDFN was based on clinical review by 3 experts blinded to the maternal blood group. In 6141 of 6796 women with known RhD status, 327 (5.3%) were RhD-negative. APO was seen in 13.3% women, and occurred twice as often in RhD-negative, as compared to RhD-positive women (aOR=2.3; 95% CI: 1.7-2.9). Clinical signs were highly suggestive of HDFN in 5.8% of RhD-negative women, as compared to 0.2% in RhD-positive women (P<.0001). Our study identifies that RhD-negative women experience a two-fold increased odds of APO, most likely due to HDFN. This highlights the need for strategies to address these maternal and child health inequities, including using anti-RhD immunoprophylaxis to prevent HDFN and screening for blood group antibodies to identify pregnancies at risk.
2026-04-08 | Understanding the consequences of being RhD immunized during pregnancy 10 years after introduction of targeted routine antenatal anti-D prophylaxis: A retrospective nationwide cohort study.
Targeted routine antenatal anti-D prophylaxis (RAADP) was introduced in Finland in 2014. The aim of this study was to assess the prevalence of anti-D immunizations among pregnant women and the severity of hemolytic disease of the fetus and newborn (HDFN) in affected pregnancies 10 years after RAADP was added to the national prevention program in the context of a rapidly declining birthrate in Finland. A nationwide, retrospective cohort study included all RhD-negative pregnancies in Finland between 2014 and 2023. Information on antenatal screening was obtained from the Finnish Red Cross Blood Service database, and obstetric and neonatal data from hospitals' records. Primary outcomes were prevalence of anti-D immunization and severity of HDFN defined as severe (intrauterine transfusion, IUT), moderate (neonatal exchange transfusion/intravenous immunoglobulin, IVIG/top-up transfusion), and mild (phototherapy). The secondary outcome was the effect of declining birth rates on the absolute numbers of anti-D pregnancies. The study included a total of 518 pregnancies of 383 women with anti-D (367 pregnancies with RhD-positive fetus/neonate). In 10 years, the prevalence of anti-D among RhD-negative pregnant women declined from 1.33% to 0.48% (reduction of 64%), and of severe HDFN from 0.20% to 0.06% (reduction of 72%). For an RhD-positive fetus, the risk of severe HDFN was 17.7% (95% CI 13.9% to 22.0%), with an overall survival rate of 90.8%. For a RhD-positive neonate not treated with IUTs, the risks of moderate and mild HDFN were each 33.0% (95% CI 24.4% to 42.6%). In addition to the effect of RAADP, the actual number of anti-D cases decreased by 34.0% due to the 24% fall in the birth rate during the study period. Ten years after the introduction of targeted RAADP, the prevalence of anti-D immunizations was reduced by more than half. Declining birth rates further reduce overall case numbers but do not lessen the complexity of care needed. A significant proportion of anti-D pregnancies still require close monitoring or intervention. Optimizing screening strategies, referral pathways, and readiness for neonatal treatment remains essential in the evolving landscape of HDFN prevention and management.
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2025-10-31 | Successful management of severe hemolytic disease of the fetus and newborn (HDFN) due to anti-Kell.
Hemolytic disease of the fetus and newborn (HDFN) is a potentially life-threatening condition, caused by maternal alloimmune antibodies targeting fetal red blood cells. This report aims to present a case of severe early-onset anti-K-mediated HDFN, managed successfully with intravenous immunoglobulin (IVIG), therapeutic plasma exchange (TPE) and intrauterine transfusion (IUT), and to discuss comparable alternative approaches reported in the literature. We treated a 32-year old woman in her third pregnancy with a high titer of anti-K alloantibodies (1:2048), detected in the first trimester. Weekly IVIG therapy of 1 g/kg was initiated at 15 weeks of gestation, followed by four TPEs and two IUTs. Due to suspected fetal anemia at 33 weeks of gestation, we opted for delivery. The newborn required phototherapy and erythropoietin treatment, with normal development at age two. To contextualize our approach, we reviewed published cases of anti-K-mediated HDFN and compiled a comparative table of treatment strategies and outcomes. Analysis showed that treatment protocols varied in IVIG dosing, TPE use, and timing, reflecting the absence of standardized approaches. These strategies were associated with delayed IUT and improved neonatal outcomes following prior fetal losses. Our case, along with the review of published cases, supports the use of IVIG, with or without TPE, in managing anti-K alloimmunized pregnancies. The variability in treatment approaches underscores the need for individualized care based on maternal antibody titers, fetal antigen status, and disease progression, while emphasizing the importance of standardized protocols and prospective studies to guide optimal management.
2025-08-03 | Understanding, detecting, and managing the "late" anemia of hemolytic disease of the fetus and newborn.
The "late" anemia of hemolytic disease of the fetus and newborn (HDFN), first described over 65 years ago, remains incompletely understood and inconsistently treated. We suspect that deficiencies in understanding its pathogenesis and fostering uniformity in its management could be remedied by teams working collaboratively to test the best ideas through multicentered trials. We begin this review by proposing a data-based definition of anemia, and of "severe" anemia, among infants at birth and during the neonatal period. We then review early as well as recent reports of the "late" anemia of HDFN, suggesting that two pathogenic forms of the condition exist; hemolytic vs. non-hemolytic (hypoproductive). We then review the use of a noninvasive and rapid means of differentiating between these two possibilities, in any given case. Next, we review means of either preventing the "late" anemia or treating it without red blood cell transfusions, using erythropoietic stimulating agents (darbepoetin or erythropoietin). We present our preferred method, using darbepoetin, and explain what we see as the chief advantages. We call for the development of transfusion stewardship programs in each NICU, to establish NICU transfusion guidelines, periodically evaluate compliance, and provide advice for problem cases. In addition, these programs can endorse a consistent approach to managing neonates with HDFN, during their NICU stay and for the weeks after discharge. We end the review with a gap analysis and a call for new focused research aimed at producing better outcomes for these patients, and less uncertainty and stress for these families.
2024-05-10 | Evaluation of erythrocyte and reticulocyte indices in a newborn with severe hemolytic disease
Currently, significant progress has been made in the prevention, diagnosis and treatment of hemolytic disease of the fetus and newborn. However, the development of anemia in a newborn child due to this disease remains an urgent problem for both neonatologists and pediatricians. In such children, a comprehensive assessment of the hemogram is of particular importance. The study of erythrocyte and reticulocyte parameters of a general blood test is necessary to determine prognostic criteria for the restoration of hematopoiesis and determine the status of iron deficiency. A clinical observation of a newborn child with the development of anemia due to hemolytic disease of the fetus and newborn is presented (clinical case). A dynamic analysis of reticulocyte parameters (absolute and relative numbers) and reticulocyte fractions was carried out. An increase in reticulocytes (absolute and relative numbers) was established, mainly due to the fraction of immature reticulocytes during the development of anemia in a newborn child. Such indicators as the hemoglobin content in reticulocytes, the average hemoglobin content in an erythrocyte, the average hemoglobin concentration in an erythrocyte in a general blood test in an infant during the neonatal period remained within the reference values. The data obtained made it possible to determine a personalized approach to the treatment of anemia and avoid blood transfusion in this child.
2024-01-04 | Case of Hemolytic Disease of the Fetus and Newborn Treated Without Blood Products.
Hemolytic disease of the fetus and newborn (HDFN) affects 3/100,000 to 80/100,000 patients yearly and can cause severe anemia and hyperbilirubinemia. Recombinant human erythropoietin has been used as an adjunct therapy in patients with HDFN and hypo-regenerative anemia in the setting of receiving intrauterine blood transfusions. This case describes a patient with HDFN, in which the family were Jehovah Witnesses, and blood transfusions were declined. The patient had symptomatic anemia with a hematocrit nadir of 18.6%. The patient was successfully treated with recombinant human erythropoietin, ferrous sulfate, and folic acid, avoiding the need for transfusion.
2023-11-30 | Darbepoetin alfa to reduce transfusion episodes in infants with haemolytic disease of the fetus and newborn who are treated with intrauterine transfusions in the Netherlands: an open-label, single-centre, phase 2, randomised, controlled trial.
Up to 88% of infants with haemolytic disease of the fetus and newborn who are treated with intrauterine transfusions require erythrocyte transfusions after birth. We aimed to investigate the effect of darbepoetin alfa on the prevention of postnatal anaemia in infants with haemolytic disease of the fetus and newborn. We conducted an open-label, single-centre, phase 2 randomised controlled trial to evaluate the effect of darbepoetin alfa on the number of erythrocyte transfusions in infants with haemolytic disease of the fetus and newborn. All infants who were treated with intrauterine transfusion and born at 35 weeks of gestation or later at the Leiden University Medical Center, Leiden, Netherlands, were eligible for inclusion. Included infants were randomised by computer at birth to treatment with 10 μg/kg darbepoetin alfa subcutaneously once a week for 8 weeks or standard care (1:1 allocation, in varying blocks of four and six, with no stratification). Treating physicians and parents were not masked to treatment allocation, but the research team, data manager, and statistician were masked to treatment allocation during the process of data collection. The primary outcome was the number of erythrocyte transfusion episodes per infant from birth up to 3 months of life in the modified intention-to-treat population. This trial is registered with ClinicalTrials.gov (NCT03104426) and has been completed. Between Oct 31, 2017, and April 31, 2022, we recruited 76 infants, of whom 44 (58%) were randomly assigned to a treatment group (20 [45%] were allocated to receive darbepoetin alfa and 24 [55%] were allocated to receive standard care). Follow-up lasted 3 months and one infant dropped out of the trial before commencement of treatment. A significant reduction in erythrocyte transfusion episodes was identified with darbepoetin alfa treatment compared with standard care (median 1·0 [IQR 1·0-2·0] transfusion episodes vs 2·0 [1·3-3·0] transfusion episodes; p=0·0082). No adverse events were reported and no infants died during the study. Darbepoetin alfa reduced the transfusion episodes after intrauterine transfusion treatment for haemolytic disease of the fetus and newborn. Treatment with darbepoetin alfa or other types of erythropoietin should be considered as part of the postnatal treatment of severe haemolytic disease of the fetus and newborn. Sanquin Blood Supply. For the Dutch translation of the abstract see Supplementary Materials section.
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2026-04-25 | Rare antigen-negative red blood cells from pluripotent stem cells for precision transfusion medicine.
Blood bank identification of antibodies against high-prevalence antigens remains a challenge due to the scarcity of antigen-negative reagent red cells sourced from blood donors. The MAM antigen, encoded by EMP3, is one such antigen associated with red cell alloimmunization and hemolytic disease of the fetus and newborn. We used CRISPR-Cas9 gene editing to generate an EMP3 knockout (EMP3KO) induced pluripotent stem cell (iPSC) line from a type O, Rh null parent line, enabling production of rare MAM-negative red blood cells. Since a prior study suggested that loss of EMP3 may enhance erythroid proliferation, we hypothesized that EMP3KO could both yield a rare reagent cell and potentially improve erythroid expansion to support scalable production. Transcriptomic analysis allowed us to further investigate the effect of EMP3 loss in late erythroblasts. EMP3KO cells differentiated efficiently into erythroid cells, showing >95% CD235/CD71 co-expression and orthochromatic erythroblast morphology. Compared to unedited cells, no proliferative advantage was observed, contrasting with prior non-isogenic cell models. Agglutination assays confirmed complete loss of MAM antigen and demonstrated the diagnostic utility for identifying MAM antibodies. Transcriptomic profiling of EMP3KO erythroblasts revealed expression of key erythroid genes, as well as regulators of proliferation and heme metabolism, was comparable to the parent line. This study demonstrates that iPSC technology combined with gene editing can generate rare antigen-negative RBCs for immunohematology applications. Beyond MAM, this platform offers a strategy to create additional rare RBC phenotypes, advancing precision transfusion medicine and improving antibody identification against high-prevalence antigens.
2026-02-12 | AlphaGenome-enabled analysis of non-coding regulatory variants underlying RHD expression with wet-lab validation.
Systematic identification of functional non-coding regulatory variants remains a major challenge in human genetics. Conventional approaches such as large-scale CRISPR screening and genome-wide association studies (GWAS) are powerful but often prohibitively expensive, time-consuming, and experimentally intensive, limiting their scalability for locus-specific mechanistic studies. Recent advances in artificial intelligence offer the potential to partially replace or substantially augment these approaches by prioritizing regulatory variants with high functional likelihood. The RHD antigen, a major contributor to red blood cell alloimmunization, hemolytic transfusion reactions, and hemolytic disease of the fetus and newborn, serves as an excellent model for this paradigm, since coding variants alone do not fully account for differences in RHD expression. Here, we present an integrated artificial intelligence (AI)-guided and experimental framework to identify and validate functional non-coding regulatory variants governing RHD expression. We first applied AlphaGenome (AG), a deep-learning model released in 2025 for non-coding variant impact prediction, to systematically interrogate the RHD locus. By integrating multi-omics datasets, AG prioritized regulatory regions within the promoter, 5' untranslated region (5'UTR), and intragenic regions. In silico deletion- and Single Nucleotide Polymorphism (SNP)-based perturbation analyses consistently predicted that variants within the promoter and its proximal regions, as well as within intragenic regions, exert strong suppressive effects on RHD expression. To experimentally validate these predictions, we performed CRISPR-mediated base editing in K562 cells at AG-prioritized non-coding SNP sites. Editing of a high-score predicted variant (chr1:25272434 G>A) achieved efficient base conversion and was accompanied by additional nearby edits, all predicted by AG to downregulate RHD expression. In contrast, editing of low-score predicted sites (chr1:25272422 C>T) produced much smaller functional effects. Quantitative polymerase chain reaction (qPCR) analysis of full-length RHD transcripts, together with flow cytometry-based analysis of RHD expression, confirmed strong concordance between AI-based predictions and transcriptional as well as phenotypic outcomes. Taken together, our results demonstrate that the combination of AI-guided regulatory variant prioritization and targeted base editing provides a potentially scalable and cost-effective alternative to traditional CRISPR screening for decoding functional non-coding variants in blood group genes, with direct implications for genomics-based RHD typing and transfusion medicine. To our knowledge, this study also represents the first validation of AlphaGenome predictions at the phenotypic level using wet-lab experiments.
2025-12-02 | Non-invasive foetal RhD genotyping: A strategy for rationalizing anti-D immunoglobulin prophylaxis in RhD-negative pregnant women at the Hospital Italiano de Buenos Aires.
The administration of anti-D immunoglobulin achieved a significant reduction in the mortality of haemolytic disease of the foetus and the newborn due to RhD sensitization. Between 30% and 40% of this group of pregnant women, carriers of an RhD-negative foetus, would unnecessarily receive a high-cost drug, exposing them to the risks of a blood derivative. The aim of the study was to assess the accuracy of non-invasive foetal RhD genotyping at different weeks of pregnancy, to allow it to be used to determine appropriate anti-D administration. In this cross-sectional cohort study of foetal RhD genotyping, determined from cell-free foetal DNA (cffDNA) between weeks 8 and 30 of gestation, 270 samples from RhD-negative pregnant women were examined. Foetal Rh status was determined by multiplex PCR in real time, to detect targeting exons 5, 7, and 10 of the RHD gene and the SRY gene (a Y-chromosome-specific marker used to confirm male foetal sex). The performance diagnostic of the foetal RhD screen test offered a sensitivity of 100% (95% confidence interval [CI]: 98.03%-100%), a specificity of 100% (95% CI: 96.3%-100%) and an accuracy of 100%. The prevalence of RhD-negative newborns in RhD-negative pregnant women was 32.5%. The results of the study reveal that the strategy of combining three RhD exons to determine foetal RhD status is reliable, with 100% accuracy. Prenatal diagnosis showed that 32.5% of newborns were RhD negative. Using this strategy, a decrease in the use of anti-D immunoglobulin is expected.
2024-12-09 | Real-world performance of a clinical droplet digital polymerase chain reaction assay for non-invasive foetal blood group and platelet antigen genotyping of alloimmunized pregnant women with antibodies directed against RhD, RhE, Rhc, RhC, K1, HPA-1a or HPA-5b: A 1-year experience.
To test the performance of a new droplet digital polymerase chain reaction (ddPCR) non-invasive foetal blood group and platelet antigen genotyping assay in the setting of a Dutch reference laboratory for foetal blood group and platelet antigen genotyping. Our population comprised 229 consecutive alloimmunized pregnant women who presented between April 2022 and March 2023 with 250 requests for non-invasive foetal RHD, RHE, RHc, RHC, K1, HPA-1a or HPA-5b blood group and platelet antigen genotyping. Samples were genotyped for blood group and platelet antigen alleles along with methylated RASSF1a (mRASSF1a) and sex-determining region of Y (SRY) and DYS14 as positive foetal controls. Negative blood group and platelet antigen results were issued only when foetal controls were positive; otherwise, such samples were classified as inconclusive. The assay achieved a success rate of 98.4% (246 of 250) because one case was lost to follow-up, one case was solved with quantitative polymerase chain reaction (qPCR) and one case precluded foetal typing due to RHD variant mothers. Only 10 cases needed a second sample and one case a third for a valid final result. We identified 116 maternal-foetal blood group and platelet antigen incompatibilities. Clinical non-invasive foetal blood group and platelet antigen typing of alloimmunized pregnant women via ddPCR is successful and represents an improvement over qPCR because of the addition of a foetal control and because ddPCR circumvents potential interference from maternal cell-free DNA (cfDNA) background for foetal HPA-1 and K1.
2023-05-27 | Gene editing without ex vivo culture evades genotoxicity in human hematopoietic stem cells.
Gene editing the BCL11A erythroid enhancer is a validated approach to fetal hemoglobin (HbF) induction for β-hemoglobinopathy therapy, though heterogeneity in edit allele distribution and HbF response may impact its safety and efficacy. Here we compared combined CRISPR-Cas9 endonuclease editing of the BCL11A +58 and +55 enhancers with leading gene modification approaches under clinical investigation. We found that combined targeting of the BCL11A +58 and +55 enhancers with 3xNLS-SpCas9 and two sgRNAs resulted in superior HbF induction, including in engrafting erythroid cells from sickle cell disease (SCD) patient xenografts, attributable to simultaneous disruption of core half E-box/GATA motifs at both enhancers. We corroborated prior observations that double strand breaks (DSBs) could produce unintended on- target outcomes in hematopoietic stem and progenitor cells (HSPCs) such as long deletions and centromere-distal chromosome fragment loss. We show these unintended outcomes are a byproduct of cellular proliferation stimulated by ex vivo culture. Editing HSPCs without cytokine culture bypassed long deletion and micronuclei formation while preserving efficient on-target editing and engraftment function. These results indicate that nuclease editing of quiescent hematopoietic stem cells (HSCs) limits DSB genotoxicity while maintaining therapeutic potency and encourages efforts for in vivo delivery of nucleases to HSCs.
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Drug Discovery Landscape
3 orphan drug designations for Hemolytic disease due to fetomaternal alloimmunization.
3 orphan drug designations for Hemolytic disease due to fetomaternal alloimmunization.
Drug | Therapy type | Regulator | Orphan designation | Approval | Sponsor |
|---|---|---|---|---|---|
nipocalimab | antibodies | FDA | 2020-06-26 | — | Janssen Research & Development, LLC |
Anti-neonatal Fc receptor human monoclonal antibody | antibodies | EMA | 2019-10-17 | — | Janssen-Cilag International N.V. |
Trisaccharides A and B | small molecules | FDA | 1987-04-12 | — | Chembiomed, Ltd. |
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