RARE DISEASE
Combined immunodeficiency with granulomatosis
Combined immunodeficiency with granulomatosis
Combined immunodeficiency with granulomatosis
Synonyms: CID due to RAG 1/2 deficiency, Combined immunodeficiency due to RAG 1/2 deficiency
Synonyms: CID due to RAG 1/2 deficiency, Combined immunodeficiency due to RAG 1/2 deficiency
Synonyms: CID due to RAG 1/2 deficiency, Combined immunodeficiency due to RAG 1/2 deficiency
Drug discovery
0
drugs
With orphan designations
Overview
Combined immunodeficiency with granulomatosis is a rare genetic disorder characterized by immunodeficiency (recurrent/severe bacterial/viral infections), noninfectious granulomas (skin, mucosa, internal organs), and autoimmune manifestations (cytopenias, vitiligo, myasthenia gravis). Immunophenotyping reveals T/B-cell lymphopenia, hypogammaglobulinemia, and impaired adaptive immunity [1][6][11]. Granulomatous inflammation often involves multiorgan systems and may coexist with lymphoid hyperplasia [12][19].
Burden
High morbidity from granuloma-related organ damage (lungs, liver, eyes) and autoimmune complications [1][9][11]
Mortality rate ~28.5% (median age 37.5), primarily from progressive immunological complications [15]
Chronic immunosuppression increases infection risks, while untreated granulomas cause disfigurement/dysfunction [6][12]
Categories: rare genetic diseases, rare immunological diseases, rare skin diseases, rare transplant-related disorders
Research Papers
37 drug discovery papers about Combined immunodeficiency with granulomatosis, with 1 first-in-class emerging drug candidates forecasted to outperform the average preclinical success rate. Recent publications:
37 drug discovery papers about Combined immunodeficiency with granulomatosis, with 1 first-in-class emerging drug candidates forecasted to outperform the average preclinical success rate. Recent publications:
categories:
Small molecules
gene therapies
2025-12-22 | Clinical and Genetic Insights into Partial RAG Deficiency in Adults: When to Consider Hematopoietic Stem Cell Transplantation?
Introduction Recombinase activating gene (RAG) deficiency is an inborn error of immunity (IEI) due to mutations in RAG1/2, impairing band T cell receptor repertoire diversity. While typically linked to severe combined immunodeficiency (SCID) in children, partial RAG deficiency (pRD) is increasingly identified in adults with milder phenotypes, leading to delayed diagnosis and treatment challenges. This study aimed to characterize the clinical and genetic profiles of adults with pRD and examine factors influencing hematopoietic stem cell transplantation (HSCT) decision. Method A retrospective multicenter analysis was conducted on 35 adults with pRD (27 RAG1, 7 RAG2, 1 both). Data included demographics, clinical severity, complications, laboratory results, transplant indication, and outcomes. Results Patients (age 17–74; median 37) exhibited diverse phenotypes: CID with granulomas/autoimmunity (49%), common variable immune deficiency or antibody deficiency (26%), classical CID (11%), and asymptomatic (14%). Molecular diagnosis occurred in adulthood, with infections starting between ages 3–35. Eight patients underwent HSCT at a mean age of 35.8 years (range 24-42), due to progressive disease, severe granulomatous inflammation, autoimmunity, and chronic pulmonary involvement. Survival was 50% among those transplanted, with transplant-related complications. The 27 non-transplanted patients displayed heterogeneous severity. Five asymptomatic individuals remained clinically stable during follow-up. At the time of analysis, 13 of the 35 patients (37%) had died (age range 28–74), mostly from infections, respiratory failure, or malignancy. Overall survival in the cohort was 63% (22/35) underscoring the high burden of morbidity and mortality in adult patients with partial RAG deficiency, regardless of phenotype. Conclusions pRD in adults is underdiagnosed and clinically variable. Genetic testing supports diagnosis, but HSCT timing remains uncertain. Findings highlight the need for prognostic markers and early genetic screening in adults with atypical antibody deficiencies or recurrent infections. Gene therapy could become a feasible alternative in carefully selected cases.
2023-11-13 | Partial correction of immunodeficiency by lentiviral vector gene therapy in mouse models carrying Rag1 hypomorphic mutations
Introduction Recombination activating genes ( RAG ) 1 and 2 defects are the most frequent form of severe combined immunodeficiency (SCID). Patients with residual RAG activity have a spectrum of clinical manifestations ranging from Omenn syndrome to delayed-onset combined immunodeficiency, often associated with granulomas and/or autoimmunity (CID-G/AI). Lentiviral vector (LV) gene therapy (GT) has been proposed as an alternative treatment to the standard hematopoietic stem cell transplant and a clinical trial for RAG1 SCID patients recently started. However, GT in patients with hypomorphic RAG mutations poses additional risks, because of the residual endogenous RAG1 expression and the general state of immune dysregulation and associated inflammation. Methods In this study, we assessed the efficacy of GT in 2 hypomorphic Rag1 murine models (Rag1 F971L/F971L and Rag1 R972Q/R972Q ), exploiting the same LV used in the clinical trial encoding RAG1 under control of the MND promoter. Results and discussion Starting 6 weeks after transplant, GT-treated mice showed a decrease in proportion of myeloid cells and a concomitant increase of B, T and total white blood cells. However, counts remained lower than in mice transplanted with WT Lin- cells. At euthanasia, we observed a general redistribution of immune subsets in tissues, with the appearance of mature recirculating B cells in the bone marrow. In the thymus, we demonstrated correction of the block at double negative stage, with a modest improvement in the cortical/medullary ratio. Analysis of antigenspecific IgM and IgG serum levels after in vivo challenge showed an amelioration of antibody responses, suggesting that the partial immune correction could confer a clinical benefit. Notably, no overt signs of autoimmunity were detected, with B-cell activating factor decreasing to normal levels and autoantibodies remaining stable after GT. On the other hand, thymic enlargement was frequently observed, although not due to vector integration and insertional mutagenesis. In conclusion, our work shows that GT could partially alleviate the combined immunodeficiency of hypomorphic RAG1 patients and that extensive efficacy and safety studies with alternative models are required before commencing RAG gene therapy in thesehighly complex patients.
2022-07-13 | Genetically Corrected RAG2-SCID Human Hematopoietic Stem Cells Restore V(D)J-Recombinase and Rescue Lymphoid Deficiency
ABSTRACT Recombination-activating genes ( RAG1 and RAG2 ) are critical in lymphoid cell development and function for initiating the V(D)J-recombination process to generate polyclonal lymphocytes with broad antigen-specificity. Clinical manifestations of defective RAG1/2 genes range from immune dysregulation to severe combined immunodeficiencies (SCID), causing life-threatening infections and death early in life in the absence of hematopoietic cell transplantation (HCT). Haploidentical HCT without myeloablative conditioning carries a high risk of graft failure and incomplete immune reconstitution. The RAG complex is only expressed during the G0-G1 phases of the cell cycle at the early stages of T and B cell development, underscoring that a direct gene correction would capture the precise temporal expression of the endogenous gene, is a promising therapeutic approach for RAG1/2 -deficiencies. Here, we report a feasibility study using the CRISPR/Cas9-based “universal gene-correction” approach for the RAG2 locus in human hematopoietic stem/progenitor cells (HSPCs) in healthy donors and one RAG2 -SCID patient. V(D)J recombinase activity was restored following gene correction of RAG2 -SCID-derived HSPCs, resulting in the development of TCR αβ and γδ CD3 + cells and single-positive CD4 + and CD8 + lymphocytes. TCR repertoire analysis indicated a normal distribution of the CDR3 length and preserved usage of distal TRAV genes. We confirmed in vivo rescue of B-cell development, with normal IgM surface expression and a significant decrease in CD56 bright NK cells. Together, we provide specificity, toxicity, and efficacy data supporting the development of a gene-correction therapy to benefit all RAG2 -deficient patients. KEY POINTS Human hematopoietic stem cells can be corrected to restore endogenous RAG2 gene expression while preserving durable engraftment potential. Gene-corrected RAG2 locus restores V(D)J recombination in RAG2 -SCID patient stem cells, promoting T and B-cells’ receptor formation.
2020-06-13 | Preclinical Development of Autologous Hematopoietic Stem Cell-Based Gene Therapy for Immune Deficiencies: A Journey from Mouse Cage to Bed Side
Recent clinical trials using patient's own corrected hematopoietic stem cells (HSCs), such as for primary immunodeficiencies (Adenosine deaminase (ADA) deficiency, X-linked Severe Combined Immunodeficiency (SCID), X-linked chronic granulomatous disease (CGD), Wiskott-Aldrich Syndrome (WAS)), have yielded promising results in the clinic; endorsing gene therapy to become standard therapy for a number of diseases. However, the journey to achieve such a successful therapy is not easy, and several challenges have to be overcome. In this review, we will address several different challenges in the development of gene therapy for immune deficiencies using our own experience with Recombinase-activating gene 1 (RAG1) SCID as an example. We will discuss product development (targeting of the therapeutic cells and choice of a suitable vector and delivery method), the proof-of-concept (in vitro and in vivo efficacy, toxicology, and safety), and the final release steps to the clinic (scaling up, good manufacturing practice (GMP) procedures/protocols and regulatory hurdles).
2018-05-28 | Advances in genetic and molecular understanding of Omenn syndrome - implications for the future
Introduction: Omenn syndrome is a rare form of leaky severe combined immunodeficiency, characterized by a widespread thickened exfoliating, protein-losing erythrodermic rash, with scaling with severe alopecia associated with widespread lymphadenopathy and hepatosplenomegaly. Unravelling the pathophysiology has revealed new understandings of the immune system.Areas covered: The description of the clinical phenotype was followed by case descriptions of the immunopathology, description of the genetic defects and realization that Omenn syndrome was a form of severe combined immunodeficiency, with features of severe autoimmunity due to a loss of central and peripheral tolerance. Differences in recombinase activity lead to variable immunological and clinical phenotypes.Expert opinion: As Omenn syndrome is a form of severe combined immunodeficiency, universal introduction of newborn screening will have a significant impact on outcome, as earlier diagnosis will favor better transplant results. Natural killer cells display an immature phenotype, contain a higher content of perforin and demonstrate enhanced degranulation which may mediate allograft rejection, and so addition of serotherapy directed against Natural Killer cells to conditioning protocols may improve outcome. Finally, murine models utilizing genetic correction of autologous stem cells have demonstrated efficacy in curing disease and clinical trials are now in progress.
cell therapies
2022-10-14 | Allogeneic and xenogeneic lymphoid reconstitution in a RAG2−/−IL2RGy/− severe combined immunodeficient pig: A preclinical model for intrauterine hematopoietic transplantation
Mice with severe combined immunodeficiency are commonly used as hosts of human cells. Size, longevity, and physiology, however, limit the extent to which immunodeficient mice can model human systems. To address these limitations, we generated RAG2-/-IL2RGy/- immunodeficient pigs and demonstrate successful engraftment of SLA mismatched allogeneic D42 fetal liver cells, tagged with pH2B-eGFP, and human CD34+ hematopoietic stem cells after in utero cell transplantation. Following intrauterine injection at day 42-45 of gestation, fetuses were allowed to gestate to term and analyzed postnatally for the presence of pig (allogeneic) and human (xenogeneic) B cells, T-cells and NK cells in peripheral blood and other lymphoid tissues. Engraftment of allogeneic hematopoietic cells was detected based on co-expression of pH2B-eGFP and various markers of differentiation. Analysis of spleen revealed robust generation and engraftment of pH2B-eGFP mature B cells (and IgH recombination) and mature T-cells (and TCR-β recombination), T helper (CD3+CD4+) and T cytotoxic (CD3+CD8+) cells. The thymus revealed engraftment of pH2B-eGFP double negative precursors (CD4-CD8-) as well as double positive (CD4+, CD8+) precursors and single positive T-cells. After intrauterine administration of human CD34+ hematopoietic stem cells, analysis of peripheral blood and lymphoid tissues revealed the presence of human T-cells (CD3+CD4+ and CD3+CD8+) but no detectable B cells or NK cells. The frequency of human CD45+ cells in the circulation decreased rapidly and were undetectable within 2 weeks of age. The frequency of human CD45+ cells in the spleen also decreased rapidly, becoming undetectable at 3 weeks. In contrast, human CD45+CD3+T-cells comprised >70% of cells in the pig thymus at birth and persisted at the same frequency at 3 weeks. Most human CD3+ cells in the pig's thymus expressed CD4 or CD8, but few cells were double positive (CD4+ CD8+). In addition, human CD3+ cells in the pig thymus contained human T-cell excision circles (TREC), suggesting de novo development. Our data shows that the pig thymus provides a microenvironment conducive to engraftment, survival and development of human T-cells and provide evidence that the developing T-cell compartment can be populated to a significant extent by human cells in large animals.
2022-07-27 | Novel NHEJ1 pathogenic variant linked to severe combined immunodeficiency, microcephaly, and abnormal T and B cell receptor repertoires
Background During the process of generating diverse T and B cell receptor (TCR and BCR, respectively) repertoires, double-strand DNA breaks are produced. Subsequently, these breaks are corrected by a complex system led by the non-homologous end-joining (NHEJ). Pathogenic variants in genes involved in this process, such as the NHEJ1 gene, cause severe combined immunodeficiency syndrome (SCID) along with neurodevelopmental disease and sensitivity to ionizing radiation. Objective To provide new clinical and immunological insights on NHEJ1 deficiency arising from a newly diagnosed patient with severe immunodeficiency. Materials and methods A male infant, born to consanguineous parents, suspected of having primary immunodeficiency underwent immunological and genetic workup. This included a thorough assessment of T cell phenotyping and lymphocyte activation by mitogen stimulation tests, whole-exome sequencing (WES), TCR repertoire Vβ repertoire via flow cytometry analysis, and TCR and BCR repertoire analysis via next-generation sequencing (NGS). Results Clinical findings included microcephaly, recurrent pneumonia, and failure to thrive. An immune workup revealed lymphopenia, reduced T cell function, and hypogammaglobulinemia. Skewed TCR Vβ repertoire, TCR gamma (TRG) repertoire, and BCR repertoire were determined in the patient. Genetic analysis identified a novel homozygous missense pathogenic variant in XLF/Cernunnos : c.A580Ins.T; p.M194fs. The patient underwent a successful hematopoietic stem cell transplantation (HSCT). Conclusion A novel NHEJ1 pathogenic variant is reported in a patient who presented with SCID phenotype that displayed clonally expanded T and B cells. An adjusted HSCT was safe to ensure full T cell immune reconstitution.
2022-07-06 | Curative allogeneic hematopoietic stem cell transplantation following reduced toxicity conditioning in adults with primary immunodeficiency
Primary immunodeficiencies (PID) are heterogeneous inborn errors of the immune system. Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is curative and safe at the pediatric age but remains underperformed in adults. We report our experience on 32 consecutive adult patients with various PID including 17 (53%) with a combined immune deficiency, six (19%) with a disease of immune dysregulation and nine (28%) with a chronic granulomatous disease (CGD) who underwent an allo-HSCT between 2011 and 2020. The median age at transplant was 27 years (17-41). All assessable patients engrafted. The majority of patients received a fludarabine-Busulfan (FB) based regimen (FB2-3 in 16, FB4 in 12). Overall survival (OS) was 80.4% (100% for CGD and 74% for other PID patients) at 9 months and beyond (median follow-up 51.6 months). Six patients died, all in the first-year post-transplant. Cumulative incidences of grade II-IV acute GVHD/chronic GVHD were 18%/22%. Stem cell source, GVHD prophylaxis and conditioning intensity had no impact on OS. All surviving patients had over 90% donor chimerism, immune reconstitution, no sign of active PID related complications and were clinically improved. Allo-HSCT is effective in young adults PID patients with an acceptable toxicity and should be discussed in case of life-threatening PID.
2020-09-29 | Asymptomatic Infant With Atypical SCID and Novel Hypomorphic RAG Variant Identified by Newborn Screening: A Diagnostic and Treatment Dilemma
The T-cell receptor excision circle (TREC) assay was designed to detect T-cell lymphopenia (TCL) in newborns, especially to identify severe combined immunodeficiency (SCID). A spectrum of SCID variants and non-SCID conditions that present with TCL are being discovered by SCID newborn screening (NBS) with increasing frequency. Decisions for treatment are influenced by underlying genetic abnormalities. Recombination-activating gene (RAG) deficiency is one the most common causes of classical and atypical SCID and other conditions with immune dysregulation. This case report aims to highlight how NBS can expedite identification of an asymptomatic newborn with a novel hypomorphic RAG variant and a controversial immune phenotype that required in depth immune evaluation to confirm that the abnormal RAG genotype is linked to the disease and justify definitive therapy with hematopoietic stem cell transplantation (HSCT). Following identification of newborns with out of range TREC levels, the diagnostic approach followed at our center includes lymphocyte subset enumeration by flow-cytometry, quantitative serum immunoglobulin levels, lymphocyte proliferation upon mitogen stimulation and next generation DNA sequencing to search for genetic variants associated with SCID. For babies in whom novel RAG gene variants are detected, we also test for immune biomarkers, and if feasible, analyze the recombinase activity of the novel RAG variants by functional assays and T and B-cell receptor repertoire. We identified and validated pathogenicity for compound heterozygous hypomorphic RAG1 variants in an asymptomatic newborn with undetectable TRECs and controversial immunological phenotype with severe TCL, but normal B cell count and lymphocyte proliferation upon mitogen stimulation. Due to the potential for severe complications with infection and immune dysregulation, the patient underwent a matched unrelated HSCT and is doing well 15 months post-HSCT. In conclusion, partial RAG deficiency can be detected by NBS in some cases such as ours. In case of an atypical immune phenotype and novel RAG gene variants, in vivo and in vitro studies are needed to confirm causative association and expedite treatment with HSCT due to risk of serious infection and non-infectious complications.
2020-06-10 | The Clinical and Genetic Spectrum of 82 Patients With RAG Deficiency Including a c.256_257delAA Founder Variant in Slavic Countries
BACKGROUND. Variants in recombination-activating genes (RAG) are common genetic causes of autosomal recessive forms of combined immunodeficiencies (CID) ranging from severe combined immunodeficiency (SCID), Omenn syndrome (OS), leaky SCID and CID with granulomas and/or autoimmunity (CID-G/AI) and even milder presentation with antibody deficiency. OBJECTIVE. We aim to estimate the incidence, clinical presentation, genetic variability and treatment outcome with geographic distribution of patients with the RAG defects in populations inhabiting South, West and East Slavic countries. METHODS. Demographic, clinical and laboratory data were collected from RAG deficient patients of Slavic origin via chart review, retrospectively. Recombinase activity was determined in vitro by flow cytometry-based assay. RESULTS. Based on the clinical and immunologic phenotype, our cohort of 82 patients from 68 families represented a wide spectrum of RAG deficiencies, including SCID (n=20), OS (n=37) and LS/CID (n=25) phenotypes. Sixty-seven (81.7%) patients carried RAG1 and 15 patients (18.3%) carried RAG2 biallelic variants. We estimate that the minimal annual incidence of RAG deficiency in Slavic countries varies between 1 in 180,000 – 300,000 live birth and it may vary secondary to health care disparities in these regions. In our cohort, 70% (n=47) of patients with RAG1 variants carried p.K86VfsTer33 (c.256_257delAA) allele, either in homozygous (n=18, 27%) or compound heterozygous (n=29,43%) form. The majority (77%) of patients with homozygous RAG1 p.K86VfsTer33 variant originated from Vistula watershed area in Central and Eastern Poland, and compound heterozygote cases distributed among all Slavic countries except Bulgaria. Clinical and immunological presentation of homozygous RAG1 p.K86fsTer33 cases was highly diverse (SCID, OS, AS/CID) suggestive of strong influence of additional genetic and/or epigenetic factors in shaping the final phenotype. CONCLUSION. We propose that RAG1 p.K86VfsTer33 is a founder variant originating from the Vistula watershed region in Poland, which may explain a high proportion of homozygous cases from Central and Eastern Poland and the presence of the variant in all Slavs. Our studies in this cohort of RAG1 founder variants confirm that clinical and immunological phenotype only partially depend on the underlying genetic defect. As access to HSCT is improving among RAG deficient patients in Eastern Europe, we anticipate improvements in survival.
small molecules
2023-07-18 | Non-Myelotoxic Agents as a Preparatory Regimen for Hematopoietic Stem Cell Gene Therapy
Abstract RAG2 deficiency is characterized by a lack of B and T lymphocytes, causing severe lethal infections. Currently, RAG2 deficiency is treated with a Hematopoietic Stem Cell transplantation (HSCT). Most conditioning regimens used before HSCT consist of alkylating myelotoxic agents with or without irradiation and affect growth and development of pediatric patients. Here, we developed a non-myelotoxic regimen using G-CSF, VLA-4I or AMD3100. These agents are known HSC mobilizers or affect bone marrow (BM) permeability and may support the homing of HSCs to the BM, without inducing major side effects. Female Rag2-/- mice were pre-treated with Busulfan (BU), G-CSF, VLA-4I or AMD3100 and transplanted with male BM cells transduced with a lentiviral vector carrying codon optimized human RAG2 (RAG2co). Peripheral blood cell counts increased significantly after G-CSF, VLA-4I and AMD3100 treatment, but not after BU. Reconstitution of PB lymphocytes was comparable for all groups with full immune reconstitution at 6 months post transplantation, despite different methods of conditioning. Survival of mice pre-treated with non-myelotoxic agents was significantly higher than after BU treatment. Here we show that the non-myelotoxic agents G-CSF, VLA-4I, and AMD3100 are highly effective as conditioning regimen before HSC gene therapy and can be used instead of BU.
2019-07-26 | Rag1 immunodeficiency‐induced early aging and senescence in zebrafish are dependent on chronic inflammation and oxidative stress
Abstract In mammals, recombination activating gene 1 (RAG1) plays a crucial role in adaptive immunity, generating a vast range of immunoglobulins. Rag1 −/− zebrafish ( Danio rerio ) are viable and reach adulthood without obvious signs of infectious disease in standard nonsterile conditions, suggesting that innate immunity could be enhanced to compensate for the lack of adaptive immunity. By using microarray analysis, we confirmed that the expression of immunity‐ and apoptosis‐related genes was increased in the rag1 −/− fish. This tool also allows us to notice alterations of the DNA repair and cell cycle mechanisms in rag1 −/− zebrafish. Several senescence and aging markers were analyzed. In addition to the lower lifespan of rag1 −/− zebrafish compared to their wild‐type (wt) siblings, rag1 −/− showed a higher incidence of cell cycle arrest and apoptosis, a greater amount of phosphorylated histone H2AX, oxidative stress and decline of the antioxidant mechanisms, an upregulated expression and activity of senescence‐related genes and senescence‐associated β‐galactosidase, respectively, diminished telomere length, and abnormal self‐renewal and repair capacities in the retina and liver. Metabolomic analysis also demonstrated clear differences between wt and rag1 −/− fish, as was the deficiency of the antioxidant metabolite l ‐acetylcarnitine (ALCAR) in rag1 −/− fish. Therefore, Rag1 activity does not seem to be limited to V(D)J recombination but is also involved in senescence and aging. Furthermore, we confirmed the senolytic effect of ABT‐263, a known senolytic compound and, for the first time, the potential in vivo senolytic activity of the antioxidant agent ALCAR, suggesting that this metabolite is essential to avoid premature aging.
2019-03-12 | Low Exposure Busulfan Conditioning to Achieve Sufficient Multilineage Chimerism in Patients with Severe Combined Immunodeficiency
After allogeneic hematopoietic cell transplantation (HCT), the minimal myeloid chimerism required for full T and B cell reconstitution in patients with severe combined immunodeficiency (SCID) is unknown. We retrospectively reviewed our experience with low-exposure busulfan (cumulative area under the curve, 30 mg·hr/L) in 10 SCID patients undergoing either first or repeat HCT from unrelated or haploidentical donors. The median busulfan dose required to achieve this exposure was 5.9 mg/kg (range, 4.8 to 9.1). With a median follow-up of 4.5 years all patients survived, with 1 requiring an additional HCT. Donor myeloid chimerism was generally >90% at 1 month post-HCT, but in most patients it fell during the next 3 months, such that 1-year median myeloid chimerism was 14% (range, 2% to 100%). Six of 10 patients had full T and B cell reconstitution, despite myeloid chimerism as low as 3%. Three patients have not recovered B cell function at over 2 years post-HCT, 2 of them in the setting of treatment with rituximab for post-HCT autoimmunity. Low-exposure busulfan was well tolerated and achieved sufficient myeloid chimerism for full immune reconstitution in over 50% of patients. However, other factors beyond busulfan exposure may also play critical roles in determining long-term myeloid chimerism and full T and B cell reconstitution.
2017-02-01 | Persistent Severe Combined Immunodeficiency with Absent Trecs Secondary to Thymectomy for TOF Repair in Early Infancy
Thymectomy in CHD was considered safe. Recently, decreased CD4, CD8, TRECS, IL-7, measles/varicella titers, skewed V beta, increased hospitalization to age 3 were reported. We describe a female with TOF/PA who underwent thymectomy/Rastelli repair DOL 13, with persistent immunologic sequelae. Repetitive TREC counts, NYS screening, Wadsworth. Second opinion age 1 with failure to thrive (less than 3rd percentile weight/age) despite gastrostomy 27 kcal/oz Alimentum, reflux on BID omeprazole, chronic eczema, watery diarrhea requiring admission; lower GI bleeding on breast milk, hives/vomiting with milk, chronic congestion; prick positive milk, repeat negative, RAST 2.92 ku/L, TC 99 normal emptying. 30 kcal/oz NEOCATE JR, 10 mg bid Nexium powder started. Immune studies: CD3 630, CD4 423, CD8 192, CD16 766, CD19 1137; IgG 400, IgM 63, IgE 8, IgA 32, 12/23 Strep. pneumoniae titers above 2; Tetanus AB undetectable, mitogen to Tetanus, Streptolysin O, Candida reduced. TREC 1317 at birth; age 15 m TREC 0,0,0, 26, and 85 run 5 times. Bactrim prophylaxis TIW and Gammagard 10% 150 mg/kg/week SC was commenced. 19 month EGD/sigmoidoscopy showed reflux/gastritis. Age 2.5: 8/23 pneumococcal titers over 2, CD3 288, CD4 224, CD8 61, CD16 210, CD19 746; TREC 13,0,0. At 35 m oral milk challenge passed; weight 25%; normal stools, cognitive development, and minimal eczema. Thymectomy can cause SCID symptoms of impaired tolerance in the absence of infections. Immune defects may persist beyond 3 and improve with treatment. Sparing thymic tissue intraoperatively should be reexamined, postoperative CHD patients immune function followed.
antibodies
2025-10-27 | Rubella-associated granuloma in a patient with a compound heterozygous RAG1 defect and review of the literature.
Recombination-activating gene (RAG) 1-2 deficiencies have a phenotype spectrum from severe combined to combined immunodeficiency (CID). We presented a comprehensive immunologic/genetic/radiologic/pathological, and virologic evaluation results of a patient with granuloma and reviewed the medical literature in 2022-2025 period for rubella virus (RuV)-associated granulomas in inborn errors of immunity (IEI). We evaluated a 17-year-old male patient with a necrotic, ulcerated, and exudative lesion extending over the right foot and leg at the edge of amputation. He had a history of recurrent pneumonia and bronchiectasis. Further evaluation revealed systemic granulomas (skin, spleen) in addition to the extremity lesions and low T- and B-, and naive CD4 + T cell numbers. In addition to a defined heterozygous RAG1 mutation(c.1421 G > A, R474H) detected with NGS PID-panel analysis, Sanger sequencing analysis confirmed patient`s CID diagnosis by revealing another heterozygous mutation(c.1181 G > A, R394Q). Histopathology demonstrated necrotizing granulomas with vasculitis and RT-PCR study from the splenic granulomas revealed RuV. The ulceration and exudative extremity lesions regressed with a scar within two months after the initiation of the anti-TNF therapy. In addition to CID therapy, hematopoietic stem cell transplantation was planned from his HLA-matched sibling donor. RuV-associated granuloma usually develop in the first 12 years and accompany gene defects related to Griscelli disease and familial hemophagocytic lymphohistiocytosis (HLH) in the medical literature. Early, comprehensive diagnostic workup for granuloma could further reveal the RuV's role in granulomatous inflammation in IEI, leading to targeted therapy to improve outcomes. Thorough genetic investigation in the presence of granuloma is crucial.
2019-07-05 | Arthritis in Two Patients With Partial Recombination Activating Gene Deficiency
Autoimmunity is becoming an increasingly recognized complication in patients with primary immunodeficiencies (PIDs), including a variety of combined immune deficiencies such as Recombination Activating Gene (RAG) defects. The approach to treating autoimmunity in PID patients is complex, requiring a balance between immunosuppression and susceptibility to infection. Inflammatory arthritis is a feature of immune dysregulation in many PIDs, and the optimal treatment may differ from first line therapies that usually consist of disease-modifying anti rheumatic drugs (DMARDs). An example of mechanism-based therapy of arthritis in PID uses blockade of IL-6 signaling with tocilizumab for patients with STAT 3 gain-of-function (GOF) mutation and augmented IL-6 pathway. Herein, we describe two PID cases with arthritis who were found to have defects in RAG. One patient with refractory inflammatory arthritis experienced remarkable improvement in symptoms with tocilizumab therapy. Arthritis can be a clinical feature of immune dysregulation in RAG deficiency, and tocilizumab therapy has been suggested to have utility in treatment of arthritis in RAG deficiency.
2017-07-17 | Natural Killer Cells from Patients with Recombinase-Activating Gene and Non-Homologous End Joining Gene Defects Comprise a Higher Frequency of CD56bright NKG2A+++ Cells, and Yet Display Increased Degranulation and Higher Perforin Content
Mutations of the recombinase-activating genes 1 and 2 (RAG1 and RAG2) in humans are associated with a broad range of phenotypes. For patients with severe clinical presentation, hematopoietic stem cell transplantation (HSCT) represents the only curative treatment; however, high rates of graft failure and incomplete immune reconstitution have been observed, especially after unconditioned haploidentical transplantation. Studies in mice have shown that Rag-/- natural killer (NK) cells have a mature phenotype, reduced fitness, and increased cytotoxicity. We aimed to analyze NK cell phenotype and function in patients with mutations in RAG and in non-homologous end joining (NHEJ) genes. Here, we provide evidence that NK cells from these patients have an immature phenotype, with significant expansion of CD56bright CD16-/int CD57- cells, yet increased degranulation and high perforin content. Correlation was observed between in vitro recombinase activity of the mutant proteins, NK cell abnormalities, and in vivo clinical phenotype. Addition of serotherapy in the conditioning regimen, with the aim of depleting the autologous NK cell compartment, may be important to facilitate engraftment and immune reconstitution in patients with RAG and NHEJ defects treated by HSCT.
gene therapies
2025-12-22 | Clinical and Genetic Insights into Partial RAG Deficiency in Adults: When to Consider Hematopoietic Stem Cell Transplantation?
Introduction Recombinase activating gene (RAG) deficiency is an inborn error of immunity (IEI) due to mutations in RAG1/2, impairing band T cell receptor repertoire diversity. While typically linked to severe combined immunodeficiency (SCID) in children, partial RAG deficiency (pRD) is increasingly identified in adults with milder phenotypes, leading to delayed diagnosis and treatment challenges. This study aimed to characterize the clinical and genetic profiles of adults with pRD and examine factors influencing hematopoietic stem cell transplantation (HSCT) decision. Method A retrospective multicenter analysis was conducted on 35 adults with pRD (27 RAG1, 7 RAG2, 1 both). Data included demographics, clinical severity, complications, laboratory results, transplant indication, and outcomes. Results Patients (age 17–74; median 37) exhibited diverse phenotypes: CID with granulomas/autoimmunity (49%), common variable immune deficiency or antibody deficiency (26%), classical CID (11%), and asymptomatic (14%). Molecular diagnosis occurred in adulthood, with infections starting between ages 3–35. Eight patients underwent HSCT at a mean age of 35.8 years (range 24-42), due to progressive disease, severe granulomatous inflammation, autoimmunity, and chronic pulmonary involvement. Survival was 50% among those transplanted, with transplant-related complications. The 27 non-transplanted patients displayed heterogeneous severity. Five asymptomatic individuals remained clinically stable during follow-up. At the time of analysis, 13 of the 35 patients (37%) had died (age range 28–74), mostly from infections, respiratory failure, or malignancy. Overall survival in the cohort was 63% (22/35) underscoring the high burden of morbidity and mortality in adult patients with partial RAG deficiency, regardless of phenotype. Conclusions pRD in adults is underdiagnosed and clinically variable. Genetic testing supports diagnosis, but HSCT timing remains uncertain. Findings highlight the need for prognostic markers and early genetic screening in adults with atypical antibody deficiencies or recurrent infections. Gene therapy could become a feasible alternative in carefully selected cases.
2023-11-13 | Partial correction of immunodeficiency by lentiviral vector gene therapy in mouse models carrying Rag1 hypomorphic mutations
Introduction Recombination activating genes ( RAG ) 1 and 2 defects are the most frequent form of severe combined immunodeficiency (SCID). Patients with residual RAG activity have a spectrum of clinical manifestations ranging from Omenn syndrome to delayed-onset combined immunodeficiency, often associated with granulomas and/or autoimmunity (CID-G/AI). Lentiviral vector (LV) gene therapy (GT) has been proposed as an alternative treatment to the standard hematopoietic stem cell transplant and a clinical trial for RAG1 SCID patients recently started. However, GT in patients with hypomorphic RAG mutations poses additional risks, because of the residual endogenous RAG1 expression and the general state of immune dysregulation and associated inflammation. Methods In this study, we assessed the efficacy of GT in 2 hypomorphic Rag1 murine models (Rag1 F971L/F971L and Rag1 R972Q/R972Q ), exploiting the same LV used in the clinical trial encoding RAG1 under control of the MND promoter. Results and discussion Starting 6 weeks after transplant, GT-treated mice showed a decrease in proportion of myeloid cells and a concomitant increase of B, T and total white blood cells. However, counts remained lower than in mice transplanted with WT Lin- cells. At euthanasia, we observed a general redistribution of immune subsets in tissues, with the appearance of mature recirculating B cells in the bone marrow. In the thymus, we demonstrated correction of the block at double negative stage, with a modest improvement in the cortical/medullary ratio. Analysis of antigenspecific IgM and IgG serum levels after in vivo challenge showed an amelioration of antibody responses, suggesting that the partial immune correction could confer a clinical benefit. Notably, no overt signs of autoimmunity were detected, with B-cell activating factor decreasing to normal levels and autoantibodies remaining stable after GT. On the other hand, thymic enlargement was frequently observed, although not due to vector integration and insertional mutagenesis. In conclusion, our work shows that GT could partially alleviate the combined immunodeficiency of hypomorphic RAG1 patients and that extensive efficacy and safety studies with alternative models are required before commencing RAG gene therapy in thesehighly complex patients.
2022-07-13 | Genetically Corrected RAG2-SCID Human Hematopoietic Stem Cells Restore V(D)J-Recombinase and Rescue Lymphoid Deficiency
ABSTRACT Recombination-activating genes ( RAG1 and RAG2 ) are critical in lymphoid cell development and function for initiating the V(D)J-recombination process to generate polyclonal lymphocytes with broad antigen-specificity. Clinical manifestations of defective RAG1/2 genes range from immune dysregulation to severe combined immunodeficiencies (SCID), causing life-threatening infections and death early in life in the absence of hematopoietic cell transplantation (HCT). Haploidentical HCT without myeloablative conditioning carries a high risk of graft failure and incomplete immune reconstitution. The RAG complex is only expressed during the G0-G1 phases of the cell cycle at the early stages of T and B cell development, underscoring that a direct gene correction would capture the precise temporal expression of the endogenous gene, is a promising therapeutic approach for RAG1/2 -deficiencies. Here, we report a feasibility study using the CRISPR/Cas9-based “universal gene-correction” approach for the RAG2 locus in human hematopoietic stem/progenitor cells (HSPCs) in healthy donors and one RAG2 -SCID patient. V(D)J recombinase activity was restored following gene correction of RAG2 -SCID-derived HSPCs, resulting in the development of TCR αβ and γδ CD3 + cells and single-positive CD4 + and CD8 + lymphocytes. TCR repertoire analysis indicated a normal distribution of the CDR3 length and preserved usage of distal TRAV genes. We confirmed in vivo rescue of B-cell development, with normal IgM surface expression and a significant decrease in CD56 bright NK cells. Together, we provide specificity, toxicity, and efficacy data supporting the development of a gene-correction therapy to benefit all RAG2 -deficient patients. KEY POINTS Human hematopoietic stem cells can be corrected to restore endogenous RAG2 gene expression while preserving durable engraftment potential. Gene-corrected RAG2 locus restores V(D)J recombination in RAG2 -SCID patient stem cells, promoting T and B-cells’ receptor formation.
2020-06-13 | Preclinical Development of Autologous Hematopoietic Stem Cell-Based Gene Therapy for Immune Deficiencies: A Journey from Mouse Cage to Bed Side
Recent clinical trials using patient's own corrected hematopoietic stem cells (HSCs), such as for primary immunodeficiencies (Adenosine deaminase (ADA) deficiency, X-linked Severe Combined Immunodeficiency (SCID), X-linked chronic granulomatous disease (CGD), Wiskott-Aldrich Syndrome (WAS)), have yielded promising results in the clinic; endorsing gene therapy to become standard therapy for a number of diseases. However, the journey to achieve such a successful therapy is not easy, and several challenges have to be overcome. In this review, we will address several different challenges in the development of gene therapy for immune deficiencies using our own experience with Recombinase-activating gene 1 (RAG1) SCID as an example. We will discuss product development (targeting of the therapeutic cells and choice of a suitable vector and delivery method), the proof-of-concept (in vitro and in vivo efficacy, toxicology, and safety), and the final release steps to the clinic (scaling up, good manufacturing practice (GMP) procedures/protocols and regulatory hurdles).
2018-05-28 | Advances in genetic and molecular understanding of Omenn syndrome - implications for the future
Introduction: Omenn syndrome is a rare form of leaky severe combined immunodeficiency, characterized by a widespread thickened exfoliating, protein-losing erythrodermic rash, with scaling with severe alopecia associated with widespread lymphadenopathy and hepatosplenomegaly. Unravelling the pathophysiology has revealed new understandings of the immune system.Areas covered: The description of the clinical phenotype was followed by case descriptions of the immunopathology, description of the genetic defects and realization that Omenn syndrome was a form of severe combined immunodeficiency, with features of severe autoimmunity due to a loss of central and peripheral tolerance. Differences in recombinase activity lead to variable immunological and clinical phenotypes.Expert opinion: As Omenn syndrome is a form of severe combined immunodeficiency, universal introduction of newborn screening will have a significant impact on outcome, as earlier diagnosis will favor better transplant results. Natural killer cells display an immature phenotype, contain a higher content of perforin and demonstrate enhanced degranulation which may mediate allograft rejection, and so addition of serotherapy directed against Natural Killer cells to conditioning protocols may improve outcome. Finally, murine models utilizing genetic correction of autologous stem cells have demonstrated efficacy in curing disease and clinical trials are now in progress.
cell therapies
2022-10-14 | Allogeneic and xenogeneic lymphoid reconstitution in a RAG2−/−IL2RGy/− severe combined immunodeficient pig: A preclinical model for intrauterine hematopoietic transplantation
Mice with severe combined immunodeficiency are commonly used as hosts of human cells. Size, longevity, and physiology, however, limit the extent to which immunodeficient mice can model human systems. To address these limitations, we generated RAG2-/-IL2RGy/- immunodeficient pigs and demonstrate successful engraftment of SLA mismatched allogeneic D42 fetal liver cells, tagged with pH2B-eGFP, and human CD34+ hematopoietic stem cells after in utero cell transplantation. Following intrauterine injection at day 42-45 of gestation, fetuses were allowed to gestate to term and analyzed postnatally for the presence of pig (allogeneic) and human (xenogeneic) B cells, T-cells and NK cells in peripheral blood and other lymphoid tissues. Engraftment of allogeneic hematopoietic cells was detected based on co-expression of pH2B-eGFP and various markers of differentiation. Analysis of spleen revealed robust generation and engraftment of pH2B-eGFP mature B cells (and IgH recombination) and mature T-cells (and TCR-β recombination), T helper (CD3+CD4+) and T cytotoxic (CD3+CD8+) cells. The thymus revealed engraftment of pH2B-eGFP double negative precursors (CD4-CD8-) as well as double positive (CD4+, CD8+) precursors and single positive T-cells. After intrauterine administration of human CD34+ hematopoietic stem cells, analysis of peripheral blood and lymphoid tissues revealed the presence of human T-cells (CD3+CD4+ and CD3+CD8+) but no detectable B cells or NK cells. The frequency of human CD45+ cells in the circulation decreased rapidly and were undetectable within 2 weeks of age. The frequency of human CD45+ cells in the spleen also decreased rapidly, becoming undetectable at 3 weeks. In contrast, human CD45+CD3+T-cells comprised >70% of cells in the pig thymus at birth and persisted at the same frequency at 3 weeks. Most human CD3+ cells in the pig's thymus expressed CD4 or CD8, but few cells were double positive (CD4+ CD8+). In addition, human CD3+ cells in the pig thymus contained human T-cell excision circles (TREC), suggesting de novo development. Our data shows that the pig thymus provides a microenvironment conducive to engraftment, survival and development of human T-cells and provide evidence that the developing T-cell compartment can be populated to a significant extent by human cells in large animals.
2022-07-27 | Novel NHEJ1 pathogenic variant linked to severe combined immunodeficiency, microcephaly, and abnormal T and B cell receptor repertoires
Background During the process of generating diverse T and B cell receptor (TCR and BCR, respectively) repertoires, double-strand DNA breaks are produced. Subsequently, these breaks are corrected by a complex system led by the non-homologous end-joining (NHEJ). Pathogenic variants in genes involved in this process, such as the NHEJ1 gene, cause severe combined immunodeficiency syndrome (SCID) along with neurodevelopmental disease and sensitivity to ionizing radiation. Objective To provide new clinical and immunological insights on NHEJ1 deficiency arising from a newly diagnosed patient with severe immunodeficiency. Materials and methods A male infant, born to consanguineous parents, suspected of having primary immunodeficiency underwent immunological and genetic workup. This included a thorough assessment of T cell phenotyping and lymphocyte activation by mitogen stimulation tests, whole-exome sequencing (WES), TCR repertoire Vβ repertoire via flow cytometry analysis, and TCR and BCR repertoire analysis via next-generation sequencing (NGS). Results Clinical findings included microcephaly, recurrent pneumonia, and failure to thrive. An immune workup revealed lymphopenia, reduced T cell function, and hypogammaglobulinemia. Skewed TCR Vβ repertoire, TCR gamma (TRG) repertoire, and BCR repertoire were determined in the patient. Genetic analysis identified a novel homozygous missense pathogenic variant in XLF/Cernunnos : c.A580Ins.T; p.M194fs. The patient underwent a successful hematopoietic stem cell transplantation (HSCT). Conclusion A novel NHEJ1 pathogenic variant is reported in a patient who presented with SCID phenotype that displayed clonally expanded T and B cells. An adjusted HSCT was safe to ensure full T cell immune reconstitution.
2022-07-06 | Curative allogeneic hematopoietic stem cell transplantation following reduced toxicity conditioning in adults with primary immunodeficiency
Primary immunodeficiencies (PID) are heterogeneous inborn errors of the immune system. Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is curative and safe at the pediatric age but remains underperformed in adults. We report our experience on 32 consecutive adult patients with various PID including 17 (53%) with a combined immune deficiency, six (19%) with a disease of immune dysregulation and nine (28%) with a chronic granulomatous disease (CGD) who underwent an allo-HSCT between 2011 and 2020. The median age at transplant was 27 years (17-41). All assessable patients engrafted. The majority of patients received a fludarabine-Busulfan (FB) based regimen (FB2-3 in 16, FB4 in 12). Overall survival (OS) was 80.4% (100% for CGD and 74% for other PID patients) at 9 months and beyond (median follow-up 51.6 months). Six patients died, all in the first-year post-transplant. Cumulative incidences of grade II-IV acute GVHD/chronic GVHD were 18%/22%. Stem cell source, GVHD prophylaxis and conditioning intensity had no impact on OS. All surviving patients had over 90% donor chimerism, immune reconstitution, no sign of active PID related complications and were clinically improved. Allo-HSCT is effective in young adults PID patients with an acceptable toxicity and should be discussed in case of life-threatening PID.
2020-09-29 | Asymptomatic Infant With Atypical SCID and Novel Hypomorphic RAG Variant Identified by Newborn Screening: A Diagnostic and Treatment Dilemma
The T-cell receptor excision circle (TREC) assay was designed to detect T-cell lymphopenia (TCL) in newborns, especially to identify severe combined immunodeficiency (SCID). A spectrum of SCID variants and non-SCID conditions that present with TCL are being discovered by SCID newborn screening (NBS) with increasing frequency. Decisions for treatment are influenced by underlying genetic abnormalities. Recombination-activating gene (RAG) deficiency is one the most common causes of classical and atypical SCID and other conditions with immune dysregulation. This case report aims to highlight how NBS can expedite identification of an asymptomatic newborn with a novel hypomorphic RAG variant and a controversial immune phenotype that required in depth immune evaluation to confirm that the abnormal RAG genotype is linked to the disease and justify definitive therapy with hematopoietic stem cell transplantation (HSCT). Following identification of newborns with out of range TREC levels, the diagnostic approach followed at our center includes lymphocyte subset enumeration by flow-cytometry, quantitative serum immunoglobulin levels, lymphocyte proliferation upon mitogen stimulation and next generation DNA sequencing to search for genetic variants associated with SCID. For babies in whom novel RAG gene variants are detected, we also test for immune biomarkers, and if feasible, analyze the recombinase activity of the novel RAG variants by functional assays and T and B-cell receptor repertoire. We identified and validated pathogenicity for compound heterozygous hypomorphic RAG1 variants in an asymptomatic newborn with undetectable TRECs and controversial immunological phenotype with severe TCL, but normal B cell count and lymphocyte proliferation upon mitogen stimulation. Due to the potential for severe complications with infection and immune dysregulation, the patient underwent a matched unrelated HSCT and is doing well 15 months post-HSCT. In conclusion, partial RAG deficiency can be detected by NBS in some cases such as ours. In case of an atypical immune phenotype and novel RAG gene variants, in vivo and in vitro studies are needed to confirm causative association and expedite treatment with HSCT due to risk of serious infection and non-infectious complications.
2020-06-10 | The Clinical and Genetic Spectrum of 82 Patients With RAG Deficiency Including a c.256_257delAA Founder Variant in Slavic Countries
BACKGROUND. Variants in recombination-activating genes (RAG) are common genetic causes of autosomal recessive forms of combined immunodeficiencies (CID) ranging from severe combined immunodeficiency (SCID), Omenn syndrome (OS), leaky SCID and CID with granulomas and/or autoimmunity (CID-G/AI) and even milder presentation with antibody deficiency. OBJECTIVE. We aim to estimate the incidence, clinical presentation, genetic variability and treatment outcome with geographic distribution of patients with the RAG defects in populations inhabiting South, West and East Slavic countries. METHODS. Demographic, clinical and laboratory data were collected from RAG deficient patients of Slavic origin via chart review, retrospectively. Recombinase activity was determined in vitro by flow cytometry-based assay. RESULTS. Based on the clinical and immunologic phenotype, our cohort of 82 patients from 68 families represented a wide spectrum of RAG deficiencies, including SCID (n=20), OS (n=37) and LS/CID (n=25) phenotypes. Sixty-seven (81.7%) patients carried RAG1 and 15 patients (18.3%) carried RAG2 biallelic variants. We estimate that the minimal annual incidence of RAG deficiency in Slavic countries varies between 1 in 180,000 – 300,000 live birth and it may vary secondary to health care disparities in these regions. In our cohort, 70% (n=47) of patients with RAG1 variants carried p.K86VfsTer33 (c.256_257delAA) allele, either in homozygous (n=18, 27%) or compound heterozygous (n=29,43%) form. The majority (77%) of patients with homozygous RAG1 p.K86VfsTer33 variant originated from Vistula watershed area in Central and Eastern Poland, and compound heterozygote cases distributed among all Slavic countries except Bulgaria. Clinical and immunological presentation of homozygous RAG1 p.K86fsTer33 cases was highly diverse (SCID, OS, AS/CID) suggestive of strong influence of additional genetic and/or epigenetic factors in shaping the final phenotype. CONCLUSION. We propose that RAG1 p.K86VfsTer33 is a founder variant originating from the Vistula watershed region in Poland, which may explain a high proportion of homozygous cases from Central and Eastern Poland and the presence of the variant in all Slavs. Our studies in this cohort of RAG1 founder variants confirm that clinical and immunological phenotype only partially depend on the underlying genetic defect. As access to HSCT is improving among RAG deficient patients in Eastern Europe, we anticipate improvements in survival.
small molecules
2023-07-18 | Non-Myelotoxic Agents as a Preparatory Regimen for Hematopoietic Stem Cell Gene Therapy
Abstract RAG2 deficiency is characterized by a lack of B and T lymphocytes, causing severe lethal infections. Currently, RAG2 deficiency is treated with a Hematopoietic Stem Cell transplantation (HSCT). Most conditioning regimens used before HSCT consist of alkylating myelotoxic agents with or without irradiation and affect growth and development of pediatric patients. Here, we developed a non-myelotoxic regimen using G-CSF, VLA-4I or AMD3100. These agents are known HSC mobilizers or affect bone marrow (BM) permeability and may support the homing of HSCs to the BM, without inducing major side effects. Female Rag2-/- mice were pre-treated with Busulfan (BU), G-CSF, VLA-4I or AMD3100 and transplanted with male BM cells transduced with a lentiviral vector carrying codon optimized human RAG2 (RAG2co). Peripheral blood cell counts increased significantly after G-CSF, VLA-4I and AMD3100 treatment, but not after BU. Reconstitution of PB lymphocytes was comparable for all groups with full immune reconstitution at 6 months post transplantation, despite different methods of conditioning. Survival of mice pre-treated with non-myelotoxic agents was significantly higher than after BU treatment. Here we show that the non-myelotoxic agents G-CSF, VLA-4I, and AMD3100 are highly effective as conditioning regimen before HSC gene therapy and can be used instead of BU.
2019-07-26 | Rag1 immunodeficiency‐induced early aging and senescence in zebrafish are dependent on chronic inflammation and oxidative stress
Abstract In mammals, recombination activating gene 1 (RAG1) plays a crucial role in adaptive immunity, generating a vast range of immunoglobulins. Rag1 −/− zebrafish ( Danio rerio ) are viable and reach adulthood without obvious signs of infectious disease in standard nonsterile conditions, suggesting that innate immunity could be enhanced to compensate for the lack of adaptive immunity. By using microarray analysis, we confirmed that the expression of immunity‐ and apoptosis‐related genes was increased in the rag1 −/− fish. This tool also allows us to notice alterations of the DNA repair and cell cycle mechanisms in rag1 −/− zebrafish. Several senescence and aging markers were analyzed. In addition to the lower lifespan of rag1 −/− zebrafish compared to their wild‐type (wt) siblings, rag1 −/− showed a higher incidence of cell cycle arrest and apoptosis, a greater amount of phosphorylated histone H2AX, oxidative stress and decline of the antioxidant mechanisms, an upregulated expression and activity of senescence‐related genes and senescence‐associated β‐galactosidase, respectively, diminished telomere length, and abnormal self‐renewal and repair capacities in the retina and liver. Metabolomic analysis also demonstrated clear differences between wt and rag1 −/− fish, as was the deficiency of the antioxidant metabolite l ‐acetylcarnitine (ALCAR) in rag1 −/− fish. Therefore, Rag1 activity does not seem to be limited to V(D)J recombination but is also involved in senescence and aging. Furthermore, we confirmed the senolytic effect of ABT‐263, a known senolytic compound and, for the first time, the potential in vivo senolytic activity of the antioxidant agent ALCAR, suggesting that this metabolite is essential to avoid premature aging.
2019-03-12 | Low Exposure Busulfan Conditioning to Achieve Sufficient Multilineage Chimerism in Patients with Severe Combined Immunodeficiency
After allogeneic hematopoietic cell transplantation (HCT), the minimal myeloid chimerism required for full T and B cell reconstitution in patients with severe combined immunodeficiency (SCID) is unknown. We retrospectively reviewed our experience with low-exposure busulfan (cumulative area under the curve, 30 mg·hr/L) in 10 SCID patients undergoing either first or repeat HCT from unrelated or haploidentical donors. The median busulfan dose required to achieve this exposure was 5.9 mg/kg (range, 4.8 to 9.1). With a median follow-up of 4.5 years all patients survived, with 1 requiring an additional HCT. Donor myeloid chimerism was generally >90% at 1 month post-HCT, but in most patients it fell during the next 3 months, such that 1-year median myeloid chimerism was 14% (range, 2% to 100%). Six of 10 patients had full T and B cell reconstitution, despite myeloid chimerism as low as 3%. Three patients have not recovered B cell function at over 2 years post-HCT, 2 of them in the setting of treatment with rituximab for post-HCT autoimmunity. Low-exposure busulfan was well tolerated and achieved sufficient myeloid chimerism for full immune reconstitution in over 50% of patients. However, other factors beyond busulfan exposure may also play critical roles in determining long-term myeloid chimerism and full T and B cell reconstitution.
2017-02-01 | Persistent Severe Combined Immunodeficiency with Absent Trecs Secondary to Thymectomy for TOF Repair in Early Infancy
Thymectomy in CHD was considered safe. Recently, decreased CD4, CD8, TRECS, IL-7, measles/varicella titers, skewed V beta, increased hospitalization to age 3 were reported. We describe a female with TOF/PA who underwent thymectomy/Rastelli repair DOL 13, with persistent immunologic sequelae. Repetitive TREC counts, NYS screening, Wadsworth. Second opinion age 1 with failure to thrive (less than 3rd percentile weight/age) despite gastrostomy 27 kcal/oz Alimentum, reflux on BID omeprazole, chronic eczema, watery diarrhea requiring admission; lower GI bleeding on breast milk, hives/vomiting with milk, chronic congestion; prick positive milk, repeat negative, RAST 2.92 ku/L, TC 99 normal emptying. 30 kcal/oz NEOCATE JR, 10 mg bid Nexium powder started. Immune studies: CD3 630, CD4 423, CD8 192, CD16 766, CD19 1137; IgG 400, IgM 63, IgE 8, IgA 32, 12/23 Strep. pneumoniae titers above 2; Tetanus AB undetectable, mitogen to Tetanus, Streptolysin O, Candida reduced. TREC 1317 at birth; age 15 m TREC 0,0,0, 26, and 85 run 5 times. Bactrim prophylaxis TIW and Gammagard 10% 150 mg/kg/week SC was commenced. 19 month EGD/sigmoidoscopy showed reflux/gastritis. Age 2.5: 8/23 pneumococcal titers over 2, CD3 288, CD4 224, CD8 61, CD16 210, CD19 746; TREC 13,0,0. At 35 m oral milk challenge passed; weight 25%; normal stools, cognitive development, and minimal eczema. Thymectomy can cause SCID symptoms of impaired tolerance in the absence of infections. Immune defects may persist beyond 3 and improve with treatment. Sparing thymic tissue intraoperatively should be reexamined, postoperative CHD patients immune function followed.
antibodies
2025-10-27 | Rubella-associated granuloma in a patient with a compound heterozygous RAG1 defect and review of the literature.
Recombination-activating gene (RAG) 1-2 deficiencies have a phenotype spectrum from severe combined to combined immunodeficiency (CID). We presented a comprehensive immunologic/genetic/radiologic/pathological, and virologic evaluation results of a patient with granuloma and reviewed the medical literature in 2022-2025 period for rubella virus (RuV)-associated granulomas in inborn errors of immunity (IEI). We evaluated a 17-year-old male patient with a necrotic, ulcerated, and exudative lesion extending over the right foot and leg at the edge of amputation. He had a history of recurrent pneumonia and bronchiectasis. Further evaluation revealed systemic granulomas (skin, spleen) in addition to the extremity lesions and low T- and B-, and naive CD4 + T cell numbers. In addition to a defined heterozygous RAG1 mutation(c.1421 G > A, R474H) detected with NGS PID-panel analysis, Sanger sequencing analysis confirmed patient`s CID diagnosis by revealing another heterozygous mutation(c.1181 G > A, R394Q). Histopathology demonstrated necrotizing granulomas with vasculitis and RT-PCR study from the splenic granulomas revealed RuV. The ulceration and exudative extremity lesions regressed with a scar within two months after the initiation of the anti-TNF therapy. In addition to CID therapy, hematopoietic stem cell transplantation was planned from his HLA-matched sibling donor. RuV-associated granuloma usually develop in the first 12 years and accompany gene defects related to Griscelli disease and familial hemophagocytic lymphohistiocytosis (HLH) in the medical literature. Early, comprehensive diagnostic workup for granuloma could further reveal the RuV's role in granulomatous inflammation in IEI, leading to targeted therapy to improve outcomes. Thorough genetic investigation in the presence of granuloma is crucial.
2019-07-05 | Arthritis in Two Patients With Partial Recombination Activating Gene Deficiency
Autoimmunity is becoming an increasingly recognized complication in patients with primary immunodeficiencies (PIDs), including a variety of combined immune deficiencies such as Recombination Activating Gene (RAG) defects. The approach to treating autoimmunity in PID patients is complex, requiring a balance between immunosuppression and susceptibility to infection. Inflammatory arthritis is a feature of immune dysregulation in many PIDs, and the optimal treatment may differ from first line therapies that usually consist of disease-modifying anti rheumatic drugs (DMARDs). An example of mechanism-based therapy of arthritis in PID uses blockade of IL-6 signaling with tocilizumab for patients with STAT 3 gain-of-function (GOF) mutation and augmented IL-6 pathway. Herein, we describe two PID cases with arthritis who were found to have defects in RAG. One patient with refractory inflammatory arthritis experienced remarkable improvement in symptoms with tocilizumab therapy. Arthritis can be a clinical feature of immune dysregulation in RAG deficiency, and tocilizumab therapy has been suggested to have utility in treatment of arthritis in RAG deficiency.
2017-07-17 | Natural Killer Cells from Patients with Recombinase-Activating Gene and Non-Homologous End Joining Gene Defects Comprise a Higher Frequency of CD56bright NKG2A+++ Cells, and Yet Display Increased Degranulation and Higher Perforin Content
Mutations of the recombinase-activating genes 1 and 2 (RAG1 and RAG2) in humans are associated with a broad range of phenotypes. For patients with severe clinical presentation, hematopoietic stem cell transplantation (HSCT) represents the only curative treatment; however, high rates of graft failure and incomplete immune reconstitution have been observed, especially after unconditioned haploidentical transplantation. Studies in mice have shown that Rag-/- natural killer (NK) cells have a mature phenotype, reduced fitness, and increased cytotoxicity. We aimed to analyze NK cell phenotype and function in patients with mutations in RAG and in non-homologous end joining (NHEJ) genes. Here, we provide evidence that NK cells from these patients have an immature phenotype, with significant expansion of CD56bright CD16-/int CD57- cells, yet increased degranulation and high perforin content. Correlation was observed between in vitro recombinase activity of the mutant proteins, NK cell abnormalities, and in vivo clinical phenotype. Addition of serotherapy in the conditioning regimen, with the aim of depleting the autologous NK cell compartment, may be important to facilitate engraftment and immune reconstitution in patients with RAG and NHEJ defects treated by HSCT.
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