The diagnosis of severe combined immunodeficiency: Implementation of the PIDTC 2022 Definitions

NF-κB pathway variants in Iranian patients with inborn errors of immunity

BACKGROUND

Clinical and immunological manifestations associated with genetic alterations are crucial for understanding inborn errors of immunity (IEI). This study aims to characterize the clinical and immunological profiles and provide the molecular features of IEI patients from the Iranian population with IEI who harbor rare variants in the nuclear factor kappa B (NF-κB) pathway.

RESEARCH DESIGN AND METHODS

Peripheral blood mononuclear cells (PBMCs) were used for immunophenotyping of B and T lymphocyte subsets via flow cytometry and for assessing T cell proliferation. Immunoblotting was performed to evaluate the expression levels of NF-κB proteins.

RESULTS

This multi-center study enrolled 16 patients with mutations in the NFKB1, NFKB2, IKBKB, and IKBKG genes. NFKB1 and NFKB2 mutations were heterozygous, while IKBKB mutations were homozygous, and the IKBKG mutation was hemizygous. Patients exhibited hypogammaglobulinemia and switched memory B cell abnormalities. Immunoblotting revealed decreased NF-κB1 protein expression in most cases. Similarly, NFKB2 mutations led to lower protein expression in unstimulated PBMCs, with mild to strong reductions after stimulation, though some cases showed no significant changes.

CONCLUSIONS

This study identifies novel IEI cases associated with NF-κB pathway defects. Further comprehensive evaluation and functional analysis of these mutations are warranted to confirm their impact on disease manifestation.

Correlation Analysis of Human Immunological Indicators and Nosocomial Infections, Along With Evaluation Value for Prognosis

Objective: This study aimed to analyze the relevant risk factors for nosocomial infection (NI) in patients who were admitted to an emergency department, explore the correlation between each influencing factor and the risk of NI, and evaluate the application value of immunological indicators on the patient prognosis, all of which can provide reference for clinical guidance. Methods: We prospectively enrolled 128 patients meeting the inclusion criteria who visited the emergency department of Dongzhimen Hospital, Beijing University of Chinese Medicine, from January 1 to December 31, 2019. Basic information and serum samples were collected from the patients, and flow cytometry was used. T lymphocyte subgroups, CD3+CD4+and CD3+CD8+, and natural killer (NK) cells were measured. Patients were divided into infection group and control group according to whether nosocomial infection occurred within 48 h of admission. Age, gender, type of disease, APACHE II score, Charlton score, T lymphocyte subtypes, and NK cell values were compared, and a logistic multivariate regression analysis was conducted. A multifactor regression analysis was performed on various risk factors. The nomogram website was used to draw a nomogram model of meaningful indicators, and the receiver-operating characteristic (ROC) curve was based on experimental results. Results: Logistics multivariate regression analysis showed the Charlton score and NK cell count were independent risk factors for nosocomial infection. Cell counts for subsets CD3+CD4+ and CD3+CD8+ were protective factors, and the OR value and 95% CI were 5.199 (1.933-13.983), 1.248 (1.055-1.475), 0.851 (0.790-0.916), and 0.832 (0.711-0.973), p < 0.05. respectively. Statistical significance was set at p < 0.05.The nomogram model suggested that the area under the curve for predicting the risk of nosocomial infection was 0.920 (0.872-0.967), p < 0.001. Conclusion: Patients with low CD3+CD4+ and CD3+CD8+ T lymphocyte or high NK cell count as well as high Charlton score are more likely to have nosocomial infection. Then, we speculate that the risk of nosocomial infection within 48 h is also high for patients with underlying diseases and immune function that is affected and suppressed on admission, regardless of whether infection occurs during hospitalization.

Advancing precision care in pregnancy through a treatable fetal findings list

The use of genomic sequencing (GS) for prenatal diagnosis of fetuses with sonographic abnormalities has grown tremendously over the past decade. Fetal GS also offers an opportunity to identify incidental genomic variants that are unrelated to the fetal phenotype but may be relevant to fetal and newborn health. There are currently no guidelines for reporting incidental findings from fetal GS. In the United States, GS for adults and children is recommended to include a list of "secondary findings" genes (ACMG SF v.3.2) that are associated with disorders for which surveillance or treatment can reduce morbidity and mortality. The genes on ACMG SF v.3.2 predominantly cause adult-onset disorders. Importantly, many genetic disorders with fetal and infantile onset are treatable as well. A proposed solution is to create a "treatable fetal findings list," which can be offered to pregnant individuals undergoing fetal GS or, eventually, as a standalone cell-free fetal DNA screening test. In this integrative review, we propose criteria for a treatable fetal findings list, then identify genetic disorders with clinically available or emerging fetal interventions and those for which clinical detection and intervention in the first week of life might lead to improved outcomes. Finally, we synthesize the potential benefits, limitations, and risks of a treatable fetal findings list.

Preimplantation genetic testing for four families with severe combined immunodeficiency: Three unaffected livebirths

PURPOSE

Severe combined immunodeficiency (SCID) is a set of rare monogenic inherited diseases that together represent the most severe form of the primary immunodeficiency disease phenotype. Preimplantation genetic testing for monogenic defects (PGT-M) is an effective reproductive technology strategy to prevent disease-causing gene mutations from being transmitted to offspring. The aim of this study was to report the use of PGT-M strategy based on karyomapping in four families to avoid the birth of SCID children.

METHODS

Four couples underwent the PGT-M strategy due to SCID. The strategy of PGT-M started with a biopsy of the trophectoderm cells of embryos, and the whole genome was amplified by multiple replacement amplification (MDA). Then, the single nucleotide polymorphisms (SNPs) in the region upstream and downstream of the mutation site were subsequently identified via karyomapping, and the results were analyzed via SNPs linkage analysis. The aneuploids of the embryos were identified simultaneously. Finally, prenatal amniocentesis was used to verify the validity of the PGT-M results.

RESULTS

We identified three novel variants (case1: IL2RG c.720_726delGAGCCAC; case 3: RAG2 c.770 C > T; and case 4: LIG4 c.1347 A > T). All four couples with SCID pathogenic gene mutations were subjected to karyomapping linkage analysis, and embryos with the pathogenic gene mutation were successfully identified. Euploid blastocysts without pathogenic alleles were transplanted, and healthy offspring were ultimately born. Prenatal diagnosis also confirmed the validity of our results.

CONCLUSION

This study revealed that karyomapping is an efficient approach for identifying SCID. Through PGT-M with karyomapping linkage analysis, healthy babies were born to families carrying mutations in the SCID pathogenic gene.

Late effects following hematopoietic cell transplantation for severe combined immunodeficiency: critical factors and therapeutic options

INTRODUCTION

Severe combined immunodeficiency (SCID) is an inborn error of immunity that is fatal without hematopoietic cell transplantation (HCT) or gene therapy (GT). Survival outcomes have improved, largely due to implementation of SCID newborn screening. A better understanding of the long-term outcomes and late effects to address critical aspects of monitoring immune and general health life-long is needed.

AREAS COVERED

In a comprehensive review of PubMed indexed articles with publication dates 2008-2024 we describe the current knowledge of chronic and late effects (CLE) of HCT survivors for SCID as well as the role of GT and advances for specific SCID genotypes. We review factors affecting the development of CLE including disease related factors (genotype, trigger for diagnosis and presence of infection prior to HCT), transplant related factors (type of donor, conditioning regimen, immune reconstitution and graft versus host disease (GVHD) and describe causes and factors associated with higher risk for late mortality in this unique population. We further describe monitoring and potential therapeutic strategies for management of common CLE in this patient population.

EXPERT OPINION

Ongoing research efforts are needed to better describe CLE in survivors, to develop prospective clinical trials aimed at mitigating these CLE, and developing genotype-based approaches for management and follow-up of these patients.

Case report: Identification of a Chinese patient with RAG1 mutations initially presenting as autoimmune hemolytic anemia

Mutations in the recombination-activating gene 1, a pivotal component essential for V(D)J recombination and the formation of T- and B-cell receptors, can result in autoimmune hemolytic anemia, a rare hematological condition characterized by the autoantibody-mediated destruction of red blood cells. Herein, we report the case of a 1-year-and-4-month-old girl who presented with progressively aggravated anemia, fever, and cough. Autoimmune hemolytic anemia was confirmed by bone marrow aspiration and Coombs test. During treatment, the patient experienced two episodes of severe pneumonia and respiratory failure. Next-generation metagenomic sequencing of sputum samples confirmed the presence of cytomegalovirus and Pneumocystis jirovecii infections. Additionally, lymphocyte subset analysis revealed a T-B+ immunodeficiency. Whole exome and Sanger sequencing revealed a pathogenic recombinase-activating gene 1 mutation (c.2095C>T, p.Arg699Trp) and a likely pathogenic variant (c.2690G>A, p.Arg897Gln), resulting in a missense mutation in the amino acid sequence of the coding protein. Consequently, the patient was diagnosed with a recombination-activating gene 1 mutation and autoimmune hemolytic anemia as the initial presentation. This study reports a case of a recombination-activating gene 1 mutation in China and documents a combination of mutation sites and associated clinical phenotypes that were previously unreported. In this study, we outline the diverse clinical phenotypes observed in cases of recombination-activating gene 1 mutations presenting with autoimmune hemolytic anemia, aiming to facilitate timely diagnosis and appropriate treatment.

European flow cytometry quality assurance guidelines for the diagnosis of primary immune deficiencies and assessment of immune reconstitution following B cell depletion therapies and transplantation

Over the last 15 years activity of diagnostic flow cytometry services have evolved from monitoring of CD4 T cell subsets in HIV-1 infection to screening for primary and secondary immune deficiencies syndromes and assessment of immune constitution following B cell depleting therapy and transplantation. Changes in laboratory activity in high income countries have been driven by initiation of anti-retroviral therapy (ART) in HIV-1 regardless of CD4 T cell counts, increasing recognition of primary immune deficiency syndromes and the wider application of B cell depleting therapy and transplantation in clinical practice. Laboratories should use their experience in standardization and quality assurance of CD4 T cell counting in HIV-1 infection to provide immune monitoring services to patients with primary and secondary immune deficiencies. Assessment of immune reconstitution post B cell depleting agents and transplantation can also draw on the expertise acquired by flow cytometry laboratories for detection of CD34 stem cell and assessment of MRD in hematological malignancies. This guideline provides recommendations for clinical laboratories on providing flow cytometry services in screening for immune deficiencies and its emerging role immune reconstitution after B cell targeting therapies and transplantation.

IL-7-dependent and -independent lineages of IL-7R-dependent human T cells

Infants with biallelic IL7R loss-of-function variants have severe combined immune deficiency (SCID) characterized by the absence of autologous T lymphocytes, but normal counts of circulating B and NK cells (T-B+NK+ SCID). We report 6 adults (aged 22 to 59 years) from 4 kindreds and 3 ancestries (Colombian, Israeli Arab, Japanese) carrying homozygous IL7 loss-of-function variants resulting in combined immunodeficiency (CID). Deep immunophenotyping revealed relatively normal counts and/or proportions of myeloid, B, NK, and innate lymphoid cells. By contrast, the patients had profound T cell lymphopenia, with low proportions of innate-like adaptive mucosal-associated invariant T and invariant NK T cells. They also had low blood counts of T cell receptor (TCR) excision circles, recent thymic emigrant T cells and naive CD4+ T cells, and low overall TCR repertoire diversity, collectively indicating impaired thymic output. The proportions of effector memory CD4+ and CD8+ T cells were high, indicating IL-7-independent homeostatic T cell proliferation in the periphery. Intriguingly, the proportions of other T cell subsets, including TCRγδ+ T cells and some TCRαβ+ T cell subsets (including Th1, Tfh, and Treg) were little affected. Peripheral CD4+ T cells displayed poor proliferation, but normal cytokine production upon stimulation with mitogens in vitro. Thus, inherited IL-7 deficiency impairs T cell development less severely and in a more subset-specific manner than IL-7R deficiency. These findings suggest that another IL-7R-binding cytokine, possibly thymic stromal lymphopoietin, governs an IL-7-independent pathway of human T cell development.

Case report: Artificial thymic organoids facilitate clinical decisions for a patient with a TP63 variant and severe persistent T cell lymphopenia

Pathogenic variants in the transcription factor TP63 are associated with clinically overlapping syndromes including ectrodactyly-ectodermal dysplasia clefting (EEC) and ankyloblepharon-ectodermal defects-cleft lip/palate (AEC). T cell lymphopenia has rarely been described in individuals with TP63 variants and the cause of the T cell defect is unclear. Here, we present a case of a female infant born with TP63-related syndrome and profound T cell lymphopenia, first uncovered through newborn screening. Flow cytometry analysis revealed low CD4+ naïve T cells and nearly absent CD8+ T cells with intact B and NK cell compartments. A de novo heterozygous pathogenic variant c.1040 G>A (C347Y) in exon 8 of TP63 was identified. An artificial thymic organoid system, to assess the intrinsic ability of the patient's hematopoietic cells to develop into T cells, was performed twice using separate peripheral blood samples. Ex vivo T cell differentiation was evident with the artificial organoid system, suggesting that a thymic stromal cell defect may be the cause of the T cell lymphopenia. Consistent with this, interrogation of publicly available data indicated that TP63 expression in the human thymus is restricted to thymic epithelial cells. Based on these data, congenital athymia was suspected and the patient received an allogenic cultured thymus tissue implant (CTTI). This is the first report of suspected congenital athymia and attempted treatment with CTTI associated with TP63 variant. At 9 months post-implant, peripheral lymphocyte analysis revealed measurable T cell receptor excision circles and presence of CD4+ recent thymic emigrants suggestive of early thymopoiesis. She will continue regular monitoring to ensure restoration of T cell immunity.

Flow cytometry-based diagnostic approach for inborn errors of immunity: experience from Algeria

Purpose

In this study, we retrospectively reviewed the use of flow cytometry (FCM) in the diagnosis of inborn errors of immunity (IEIs) at a single center in Algeria. Sharing insights into our practical experience, we present FCM based diagnostic approaches adapted to different clinical scenarios.

Methods

Between May 2017 and February 2024, pediatric and adult patients presenting with clinical features suggestive of immunodeficiency were subjected to FCM evaluation, including lymphocyte subset analysis, detection of specific surface or intracellular proteins, and functional analysis of immune cells.

Results

Over a nearly seven-year period, our laboratory diagnosed a total of 670 patients (372 (55.5%) males and 298 (44.5%) females), distributed into 70 different IEIs belonging to 9 different categories of the International Union of Immunological Societies classification. FCM was used to diagnose and categorize IEI in 514 patients (76.7%). It provided direct diagnostic insights for IEIs such as severe combined immunodeficiency, Omenn syndrome, MHC class II deficiency, familial hemophagocytic lymphohistiocytosis, and CD55 deficiency. For certain IEIs, including hyper-IgE syndrome, STAT1-gain of function, autoimmune lymphoproliferative syndrome, and activated PI3K delta syndrome, FCM offered suggestive evidence, necessitating subsequent genetic testing for confirmation. Protein expression and functional assays played a crucial role in establishing definitive diagnoses for various disorders. To setup such diagnostic assays at high and reproducible quality, high level of expertise is required; in house reference values need to be determined and the parallel testing of healthy controls is highly recommended.

Conclusion

Flow cytometry has emerged as a highly valuable and cost-effective tool for diagnosing and studying most IEIs, particularly in low-income countries where access to genetic testing can be limited. FCM analysis could provide direct diagnostic insights for most common IEIs, offer clues to the underlying genetic defects, and/or aid in narrowing the list of putative genes to be analyzed.

Current Status of Newborn Bloodspot Screening Worldwide 2024: A Comprehensive Review of Recent Activities (2020-2023)

Newborn bloodspot screening (NBS) began in the early 1960s based on the work of Dr. Robert "Bob" Guthrie in Buffalo, NY, USA. His development of a screening test for phenylketonuria on blood absorbed onto a special filter paper and transported to a remote testing laboratory began it all. Expansion of NBS to large numbers of asymptomatic congenital conditions flourishes in many settings while it has not yet been realized in others. The need for NBS as an efficient and effective public health prevention strategy that contributes to lowered morbidity and mortality wherever it is sustained is well known in the medical field but not necessarily by political policy makers. Acknowledging the value of national NBS reports published in 2007, the authors collaborated to create a worldwide NBS update in 2015. In a continuing attempt to review the progress of NBS globally, and to move towards a more harmonized and equitable screening system, we have updated our 2015 report with information available at the beginning of 2024. Reports on sub-Saharan Africa and the Caribbean, missing in 2015, have been included. Tables popular in the previous report have been updated with an eye towards harmonized comparisons. To emphasize areas needing attention globally, we have used regional tables containing similar listings of conditions screened, numbers of screening laboratories, and time at which specimen collection is recommended. Discussions are limited to bloodspot screening.

Omenn Syndrome in Two Infants with Different Hypomorphic Variants in Janus Kinase 3

Biallelic null or hypomorphic variants in JAK3 cause SCID and less frequently Omenn syndrome. We investigated homozygous hypomorphic JAK3 mutations in two patients, and expression and function of a novel JAK3R431P variant in Omenn syndrome. Immunophenotyping of PBMC from the patient with the novel JAK3R431P variant was undertaken, by flow cytometry and Phosflow after stimulation with IL-2, IL-7, and IL-15. JAK3 expression was investigated by Western blotting. We report two patients with homozygous hypomorphic JAK3 variants and clinical features of Omenn syndrome. One patient had a previously described JAK3R775H variant, and the second had a novel JAK3R431P variant. One patient with a novel JAK3R431P variant had normal expression of JAK3 in immortalised EBV-LCL cells but reduced phosphorylation of STAT5 after stimulation with IL-2, IL-7, and IL-15 consistent with impaired kinase activity. These results suggest the JAK3R431P variant to be hypomorphic. Both patients are alive and well after allogeneic haematopoietic stem cell transplantation. They have full donor chimerism, restitution of thymopoiesis and development of appropriate antibody responses following vaccination. We expand the phenotype of hypomorphic JAK3 deficiency and demonstrate the importance of functional testing of novel variants in disease-causing genes.

Expanding the PRAAS spectrum: De novo mutations of immunoproteasome subunit β-type 10 in six infants with SCID-Omenn syndrome

Mutations in proteasome β-subunits or their chaperone and regulatory proteins are associated with proteasome-associated autoinflammatory disorders (PRAAS). We studied six unrelated infants with three de novo heterozygous missense variants in PSMB10, encoding the proteasome β2i-subunit. Individuals presented with T-B-NK± severe combined immunodeficiency (SCID) and clinical features suggestive of Omenn syndrome, including diarrhea, alopecia, and desquamating erythematous rash. Remaining T cells had limited T cell receptor repertoires, a skewed memory phenotype, and an elevated CD4/CD8 ratio. Bone marrow examination indicated severely impaired B cell maturation with limited V(D)J recombination. All infants received an allogeneic stem cell transplant and exhibited a variety of severe inflammatory complications thereafter, with 2 peri-transplant and 2 delayed deaths. The single long-term transplant survivor showed evidence for genetic rescue through revertant mosaicism overlapping the affected PSMB10 locus. The identified variants (c.166G>C [p.Asp56His] and c.601G>A/c.601G>C [p.Gly201Arg]) were predicted in silico to profoundly disrupt 20S immunoproteasome structure through impaired β-ring/β-ring interaction. Our identification of PSMB10 mutations as a cause of SCID-Omenn syndrome reinforces the connection between PRAAS-related diseases and SCID.

Mutational analysis in different genes underlying severe combined immunodeficiency in seven consanguineous Pakistani families

BACKGROUND

Severe Combined Immunodeficiency (SCID) is an autosomal recessive inborn error of immunity (IEI) characterized by recurrent chest and gastrointestinal (GI) infections and in some cases associated with life-threatening disorders.

METHODOLOGY AND RESULTS

This current study aims to unwind the molecular etiology of SCID and also extended the patients' phenotype associated with identified particular variants. Herein, we present 06 disease-causing variants identified in 07 SCID-patients in three different SCID related genes. Whole Exome Sequencing (WES) followed by Sanger Sequencing was employed to explore genetic variations. The results included identification of two previously reported heterozygous variants in homozygous form for the first time in RAG1gene [(p.Arg410Gln);(p.Arg737His)], followed by a recurrent variant (p.Trp959*) in RAG1, a novel variant in IL2RG (p.Asp48Lfs*24), a recurrent variant in IL2RG (p.Gly271Glu) and a recurrent variant in DCLRE1C (p.Arg191*) gene.

CONCLUSION

To conclude, the immune-profiling and WES revealed two novel, two as homozygous state for the first time, and two recurrent disease causing variants contributing valuably to our existing knowledge of SCID.

Assistance of next-generation sequencing for diagnosis of disseminated Bacillus Calmette-Guerin disease with X-SCID in an infant: a case report and literature review

Bacille Calmette-Guérin (BCG) is a live strain of Mycobacterium bovis (M.bovis) for use as an attenuated vaccine to prevent tuberculosis (TB) infection, while it could also lead to an infection in immunodeficient patients. M.bovis could infect patients with immunodeficiency via BCG vaccination. Disseminated BCG disease (BCGosis) is extremely rare and has a high mortality rate. This article presents a case of a 3-month-old patient with disseminated BCG infection who was initially diagnosed with hemophagocytic syndrome (HPS) and eventually found to have X-linked severe combined immunodeficiency (X-SCID). M.bovis and its drug resistance genes were identified by metagenomics next-generation sequencing (mNGS) combined with targeted next-generation sequencing (tNGS) in blood and cerebrospinal fluid. Whole exome sequencing (WES) revealed a pathogenic variant in the common γ-chain gene (IL2RG), confirming X-SCID. Finally, antituberculosis therapy and umbilical cord blood transplantation were given to the patient. He was successfully cured of BCGosis, and his immune function was restored. The mNGS combined with the tNGS provided effective methods for diagnosing rare BCG infections in children. Their combined application significantly improved the sensitivity and specificity of the detection of M.bovis.

Exonic knockout and knockin gene editing in hematopoietic stem and progenitor cells rescues RAG1 immunodeficiency

Recombination activating genes (RAGs) are tightly regulated during lymphoid differentiation, and their mutations cause a spectrum of severe immunological disorders. Hematopoietic stem and progenitor cell (HSPC) transplantation is the treatment of choice but is limited by donor availability and toxicity. To overcome these issues, we developed gene editing strategies targeting a corrective sequence into the human RAG1 gene by homology-directed repair (HDR) and validated them by tailored two-dimensional, three-dimensional, and in vivo xenotransplant platforms to assess rescue of expression and function. Whereas integration into intron 1 of RAG1 achieved suboptimal correction, in-frame insertion into exon 2 drove physiologic human RAG1 expression and activity, allowing disruption of the dominant-negative effects of unrepaired hypomorphic alleles. Enhanced HDR-mediated gene editing enabled the correction of human RAG1 in HSPCs from patients with hypomorphic RAG1 mutations to overcome T and B cell differentiation blocks. Gene correction efficiency exceeded the minimal proportion of functional HSPCs required to rescue immunodeficiency in Rag1-/- mice, supporting the clinical translation of HSPC gene editing for the treatment of RAG1 deficiency.

Purine Nucleoside Phosphorylase Deficient Severe Combined Immunodeficiencies: A Case Report and Systematic Review (1975-2022)

Purine nucleoside phosphorylase deficient severe combined immunodeficiency (PNP SCID) is one of the rare autosomal recessive primary immunodeficiency disease, and the data on epidemiology and outcome are limited. We report the successful management of a child with PNP SCID and present a systematic literature review of published case reports, case series, and cohort studies on PNP SCID listed in PubMed, Web of Science, and Scopus from 1975 until March 2022. Forty-one articles were included from the 2432 articles retrieved and included 100 PNP SCID patients worldwide. Most patients presented with recurrent infections, hypogammaglobulinaemia, autoimmune manifestations, and neurological deficits. There were six reported cases of associated malignancies, mainly lymphomas. Twenty-two patients had undergone allogeneic hematopoietic stem cell transplantation with full donor chimerism seen mainly in those receiving matched sibling donors and/or conditioning chemotherapy before the transplant. This research provides a contemporary, comprehensive overview on clinical manifestations, epidemiology, genotype mutations, and transplant outcome of PNP SCID. These data highlight the importance of screening for PNP SCID in cases presented with recurrent infections, hypogammaglobulinaemia, and neurological deficits.

Epidemiology of combined immunodeficiencies affecting cellular and humoral immunity- a multicentric retrospective cohort study from the Arabian Peninsula

AIMS

To understand the characteristics of combined immunodeficiency disorders that affect cellular and humoral immunity (CID) in the Arabian Peninsula.

METHODS

Retrospective study of 236 patients with CID from the region were enrolled from 2004 to 2022.

RESULTS

236 patients were included with a majority being profound CID. Among patients with a family history of CID, the ages at onset and diagnosis, and the delay in diagnosis were lower compared to those with no family history of CID, but this did not affect time to transplant. HSCT was performed for 51.27% of the patients with median time from diagnosis to HSCT of 6.36 months. On multivariate analysis, patients who underwent early transplant had increased odds of having CD3 count ≤1000 cell/μl, diagnosed by screening or erythroderma.

CONCLUSION

There is a delay in diagnosis and treatment of CID in our region. Establishing newborn screening programs and HSCT units in our region are the urgent need.

[Principles of the diagnostics of inborn errors of immunity]

Inborn errors of immunity (IEI) are a heterogeneous group of nearly 500 diseases characterized by a congenital dysfunction of the immune system. The vast majority of IEIs are rare diseases but all IEIs share a cumulative prevalence of 1:1200-1:2000. In addition to a pathological susceptibility to infections, IEIs can also present with lymphoproliferative, autoimmune or autoinflammatory manifestations. There is often an overlap with classical rheumatic and inflammatory disease patterns. Therefore, a basic knowledge of the clinical presentation and the diagnostics of IEIs is also relevant for the practicing rheumatologist.

Allogeneic Hematopoietic Stem Cell Transplantation Activity in Inborn Errors of Immunity in Russian Federation

PURPOSE

Allogeneic hematopoietic stem cell transplantation (HSCT) is an established therapy for many inborn errors of immunity (IEI). The indications for HSCT have expanded over the last decade. The study aimed to collect and analyze the data on HSCT activity in IEI in Russia.

METHODS

The data were collected from the Russian Primary Immunodeficiency Registry and complemented with information from five Russian pediatric transplant centers. Patients diagnosed with IEI by the age of 18 years and who received allogeneic HSCT by the end of 2020 were included.

RESULTS

From 1997 to 2020, 454 patients with IEI received 514 allogeneic HSCT. The median number of HSCTs per year has risen from 3 in 1997-2009 to 60 in 2015-2020. The most common groups of IEI were immunodeficiency affecting cellular and humoral immunity (26%), combined immunodeficiency with associated/syndromic features (28%), phagocyte defects (21%), and diseases of immune dysregulation (17%). The distribution of IEI diagnosis has changed: before 2012, the majority (65%) had severe combined immunodeficiency (SCID) and hemophagocytic lymphohistiocytosis (HLH), and after 2012, only 24% had SCID and HLH. Of 513 HSCTs, 48.5% were performed from matched-unrelated, 36.5% from mismatched-related (MMRD), and 15% from matched-related donors. In 349 transplants T-cell depletion was used: 325 TCRαβ/CD19+ depletion, 39 post-transplant cyclophosphamide, and 27 other. The proportion of MMRD has risen over the recent years.

CONCLUSION

The practice of HSCT in IEI has been changing in Russia. Expanding indications to HSCT and SCID newborn screening implementation may necessitate additional transplant beds for IEI in Russia.