A novel hemizygous CD40L mutation of X-linked hyper IgM syndromes and compound heterozygous DOCK8 mutations of hyper IgE syndromes in two Chinese families.

X-linked hyper-immunoglobulin M (X-HIGM) syndrome and autosomal recessive hyper-immunoglobulin E syndrome (HIES) are rare inborn errors of immunity characterized by recurrent infections due to immune system impairment. In this study, we identified a novel hemizygous CD40 ligand (CD40L) mutation and compound heterozygous dedicator of cytokinesis-8 (DOCK8) mutations in two Han Chinese families with X-HIGM and HIES, respectively. We aimed to investigate the association between their genotypes and phenotypes. Genomic DNA was extracted from peripheral blood samples obtained from the families. Whole exome sequencing and Sanger sequencing were performed to identify and verify pathogenic variants in the two families. Clinical analyses of the probands were also performed. A novel hemizygous mutation of CD40L in exon 2 (c.257delA) was identified in the first proband, resulting in the substitution of glycine with glutamic acid at codon 86 of the protein. This leads to premature termination of translation at downstream codon 9 (p.E86Gfs*9). Sanger sequencing confirmed that the variant was inherited from the mother. The second proband carried two novel compound heterozygous mutations in DOCK8: one at exon 14 (c.1546C > G) inherited from the father, and the other at intron 41 (c.5355 + 6C > T; splicing) inherited from the mother. This study enhances our understanding of the pathogenetic mutation spectrum of CD40L and DOCK8 genes, facilitating the prenatal diagnosis of X-HIGM and HIES and enabling timely treatment of patients.

Advanced computational analysis of CD40LG variants in atypical X-linked hyper-IgM syndrome.

X-Linked Hyper-IgM Syndrome is caused by pathogenic variants in CD40LG. Three patients with atypical clinical and immunological features were identified with variants in CD40LG requiring further characterization. Flow cytometry was used to evaluate CD40L protein expression and binding capacity to a surrogate receptor, CD40-muIg. Though functional anomalies were observed, there was still a lack of clarity regarding the underlying mechanism. We developed structural models for wild-type and the three variants of CD40L protein observed in these patients (p. Lys143Asn, Leu225Ser and Met36Arg) to evaluate structural alterations by molecular mechanic calculations, and assess protein movement by molecular dynamic simulations. These studies demonstrate that functional analysis of variants of unknown significance in CD40LG can be supplemented by advanced computational analysis in atypical clinical contexts. These studies in combination identify the deleterious effects of these variants and potential mechanisms for protein dysfunction.

[Hyper-IgM syndrome with early liver involvement]. / Síndrome de hiper-IgM con afectación hepática temprana.

INTRODUCTION: Hyper-IgM syndrome is an innate error of immunity in which there is a defect in change of isotype of immunoglobulins, with decreased values of IgG, IgA, and IgE, but normal or increased level of IgM. This predisposes to infectious processes at the respiratory and gastrointestinal levels, as well as autoimmune diseases and neoplasm. CASE REPORT: A 5 year 7-month-old boy with a history of 2 pneumonias, one of them severe, and chronic diarrhea since he was 2 years old. Persistent moderate neutropenia decreased IgG and elevated IgM. Cytometry flow confirmed absence of CD40L. Clinical evolution with early hepatic involvement. DISCUSSION: Hyper-IgM syndrome predisposes to liver damage, so a complete evaluation is required as well as early diagnosis. Active anti-infective treatment and control of the inflammatory response are key to the treatment of liver damage.

INTRODUCCIÓN: El síndrome de hiper-IgM es un error innato de la inmunidad, caracterizado por un defecto en el cambio de isotipo de inmunoglobulina, con valores disminuidos de IgG, IgA e IgE, y concentraciones normales o elevadas de IgM. Predispone a procesos infecciosos en el sistema respiratorio y aparato gastrointestinal, además de enfermedades autoinmunes y neoplasias. REPORTE DE CASO: Paciente pediátrico de género masculino, de 5 años y 7 meses de edad, con antecedente de dos cuadros de neumonía (uno de estos grave) y diarrea crónica desde los 2 años. Neutropenia moderada persistente, disminución de la concentración de IgG y elevación de IgM. La citometría de flujo confirmó la ausencia de CD40L. Durante la evolución clínica tuvo afectación hepática temprana. CONCLUSIÓn: El síndrome de hiper-IgM predispone a daño hepático, por lo que se requiere la evaluación completa y el diagnóstico oportuno. El tratamiento antiinfeccioso activo y el control de la respuesta inflamatoria son factores decisivos para establecer el tratamiento del daño hepático.

Clinical practice guideline for activated phosphatidyl inositol 3-kinase-delta syndrome in Japan.

Activated phosphatidyl inositol 3-kinase-delta syndrome (APDS) due to gain-of-function variant in the class IA PI3K catalytic subunit p110δ (responsible gene: PIK3CD) was described in 2013. The disease is characterized by recurrent airway infections and bronchiectasis. It is associated with hyper-IgM syndrome due to the defect of immunoglobulin class switch recombination and decreased CD27-positive memory B cells. Patients also suffered from immune dysregulations, such as lymphadenopathy, autoimmune cytopenia or enteropathy. T-cell dysfunction due to increased senescence is associated with a decrease in CD4-positive T lymphocytes and CD45RA-positive naive T lymphocytes, along with increased susceptibility to Epstein-Barr virus/cytomegalovirus infections. In 2014, loss-of-function (LOF) mutation of p85α (responsible gene: PIK3R1), a regulatory subunit of p110δ, was identified as a causative gene, followed in 2016 by the identification of the LOF mutation of PTEN, which dephosphorylates PIP3, leading to the differentiation of APDS1 (PIK3CD-GOF), APDS2 (PIK3R1-LOF) and APDS-L (PTEN-LOF). Since the pathophysiology of patients with APDS varies with a wide range of severity, it is crucial that patients receive appropriate treatment and management. Our research group created a disease outline and a diagnostic flow chart and summarized clinical information such as the severity classification of APDS and treatment options.

CD40LG-associated X-linked Hyper-IgM Syndrome (XHIGM) with pulmonary alveolar proteinosis: a case report.

BACKGROUND: D40LG-associated X-linked hyper-IgM syndrome with pulmonary alveolar proteinosis has rarely been reported, and its genotype-phenotypic correlation remains elusive. CASE PRESENTATION: We describe a five-month-old boy with CD40LG mutation (c.516T > A, p.Tyr172Ter) X-linked hyper-IgM syndrome with pulmonary alveolar proteinosis as the first manifestation. The patient completely recovered after immunotherapy and allogeneic hematopoietic stem cell transplantation. In addition, four previously reported patients with CD40LG mutation with pulmonary alveolar proteinosis were also analyzed. All of these patients presented with early onset of pulmonary infections and a good response to immunotherapy. The structural model of CD40LG indicated that all mutations caused the X-linked hyper-IgM syndrome with pulmonary alveolar proteinosis to be located within the tumor necrosis factor homology domain. CONCLUSIONS: A case was presented, and the characteristics of four cases of CD40LG-associated X-linked hyper-IgM syndrome with pulmonary alveolar proteinosis were summarized. The variant locations may explain the phenotypic heterogeneity of patients with the CD40LG mutation.

[Clinical effect of allogeneic hematopoietic stem cell transplantation in children with hyper-IgM syndrome]. / å¼‚åŸºå› é€ è¡€å¹²ç»†èƒžç§»æ¤æ²»ç–—å„¿ç«¥é«˜IgM综合征的临床分析.

OBJECTIVES: To evaluate the clinical effect of allogeneic hematopoietic stem cell transplantation (allo-HSCT) in children with hyper-IgM syndrome (HIGM). METHODS: A retrospective analysis was performed on the medical data of 17 children with HIGM who received allo-HSCT. The Kaplan Meier method was used for the survival analysis of the children with HIGM after allo-HSCT. RESULTS: After allo-HSCT, 16 children were diagnosed with sepsis; 14 tested positive for virus within 100 days after allo-HSCT, among whom 11 were positive for Epstein-Barr virus, 7 were positive for cytomegalovirus, and 2 were positive for JC virus; 9 children were found to have invasive fungal disease. There were 6 children with acute graft-versus-host disease and 3 children with chronic graft-versus-host disease. The median follow-up time was about 2 years, and 3 children died in the early stage after allo-HSCT. The children had an overall survival (OS) rate of 82.35%, an event-free survival (EFS) rate of 70.59%, and a disease-free survival (DFS) rate of 76.47%. The univariate analysis showed that the children receiving HLA-matched allo-HSCT had a significantly higher EFS rate than those receiving HLA-mismatched allo-HSCT (P=0.019) and that the children receiving HLA-matched unrelated allo-HSCT had significantly higher OS, EFS, and DFS rates than those receiving HLA-mismatched unrelated allo-HSCT (P<0.05). Compared with the children with fungal infection after allo-HSCT, the children without fungal infection had significantly higher EFS rate (P=0.02) and DFS rate (P=0.04). CONCLUSIONS: Allo-HSCT is an effective treatment method for children with HIGM. HLA-matched allo-HSCT and active prevention and treatment of fungal infection and opportunistic infection may help to improve the prognosis of such children.

Mobilization-based chemotherapy-free engraftment of gene-edited human hematopoietic stem cells.

Hematopoietic stem/progenitor cell gene therapy (HSPC-GT) is proving successful to treat several genetic diseases. HSPCs are mobilized, harvested, genetically corrected ex vivo, and infused, after the administration of toxic myeloablative conditioning to deplete the bone marrow (BM) for the modified cells. We show that mobilizers create an opportunity for seamless engraftment of exogenous cells, which effectively outcompete those mobilized, to repopulate the depleted BM. The competitive advantage results from the rescue during ex vivo culture of a detrimental impact of mobilization on HSPCs and can be further enhanced by the transient overexpression of engraftment effectors exploiting optimized mRNA-based delivery. We show the therapeutic efficacy in a mouse model of hyper IgM syndrome and further developed it in human hematochimeric mice, showing its applicability and versatility when coupled with gene transfer and editing strategies. Overall, our findings provide a potentially valuable strategy paving the way to broader and safer use of HSPC-GT.

X-linked hyper IgM syndrome with severe eosinophilia: a case report and review of the literature.

BACKGROUND: Hyper IgM syndromes (HIGMS) are a group of rare primary immunodeficiency disorders. There are limited reports about HIGMS combined with severe eosinophilia. CASE PRESENTATION: In this report, we described a 2-year-old boy with chronic cough and symptoms of hypoxia. Lung computed tomography (CT) scan showed that diffuse ground-glass changes and eosinophils in peripheral blood increased significantly. Subsequent tests revealed a notable decrease in serum IgG and IgA. The lymphocyte subgroup classification was basically normal. Pneumocystis jirovecii were detected from the bronchoalveolar lavage fluid (BALF) of the patient by metagenomic next-generation sequencing (mNGS). After treatments of caspofungin combined with sulfamethoxazole, intravenous immunoglobulin (IVIG) replacement and anti-inflammatory steroid, the clinical symptoms and pulmonary imaging noticeably improved. The absolute eosinophil count (AEC) also returned to normal range. X-linked hyper IgM syndrome was confirmed by gene test. Two months after the diagnosis, the patient underwent allogeneic stem cell transplantation (HSCT) and has recovered well. CONCLUSIONS: Children with HIGMS are prone to opportunistic infections such as Pneumocystis jirovecii pneumonia (PJP). Diffuse interstitial lung disease and hypoglobulinemia in a young child predict the diagnosis of a primary immunodeficiency (PID). mNGS has obvious advantages for obtaining etiological diagnosis of children with PIDs. Severe eosinophilia is rarely reported in this kind of PIDs. Considering literature review and the corresponding reaction to steroid, we proposed that eosinophilia in HIGMS might be related to infections. Steroid therapy can quickly relieve eosinophilia but is easy to rebound if the reduction is too fast. Once the diagnosis of HIGMS is confirmed, the earlier the HSCT, the better the prognosis.

A Novel AICDA Splice-Site Mutation in Two Siblings with HIGM2 Permits Somatic Hypermutation but Abrogates Mutational Targeting.

Hyper-IgM syndrome type 2 (HIGM2) is a B cell intrinsic primary immunodeficiency caused by mutations in AICDA encoding activation-induced cytidine deaminase (AID) which impair immunoglobulin class switch recombination (CSR) and somatic hypermutation (SHM). Whereas autosomal-recessive AID-deficiency (AR-AID) affects both CSR and SHM, the autosomal-dominant form (AD-AID) due to C-terminal heterozygous variants completely abolishes CSR but only partially affects SHM. AR-AID patients display enhanced germinal center (GC) reactions and autoimmune manifestations, which are not present in AD-AID, suggesting that SHM but not CSR regulates GC reactions and peripheral B cell tolerance. Herein, we describe two siblings with HIGM2 due to a novel homozygous AICDA mutation (c.428-1G > T) which disrupts the splice acceptor site of exon 4 and results in the sole expression of a truncated AID variant that lacks 10 highly conserved amino acids encoded by exon 4 (AID-ΔE4a). AID-ΔE4a patients suffered from defective CSR and enhanced GC reactions and were therefore indistinguishable from other AR-AID patients. However, the AID-ΔE4a variant only partially affected SHM as observed in AD-AID patients. In addition, AID-ΔE4a but not AD-AID patients revealed impaired targeting of mutational hotspot motives and distorted mutational patterns. Hence, qualitative defects in AID function and altered SHM rather than global decreased SHM activity may account for the disease phenotype in these patients.

Progressive Multifocal Leukoencephalopathy With Hyper-IgM Syndrome in a 6-Year-Old Boy.

Hyper-immunoglobulin (Ig) M syndrome is a congenital immunodeficiency disorder characterized by increased serum IgM with low serum IgG, IgA, and IgE. We report the case of a 6-year-old boy with hyper-IgM syndrome as an underlying disease who showed progressive multifocal leukoencephalopathy findings on brain magnetic resonance imaging after visiting the hospital due to left upper extremity muscle weakness, gait disturbance, and speech impairment. At the time of hospitalization, he was treated with steroids and intravenous immunoglobulin, and his condition improved somewhat, but 6 months later, he visited the hospital with rapid deterioration.

Transient increased immunoglobulin levels in a hyper-IgM syndrome patient with COVID-19 infection.

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic has affected millions of people around the world. This zoonotic-enveloped virus is primarily transmitted through inhalation. Infected people are commonly asymptomatic or manifest mild symptoms, including fever, cough, diarrhea, and fatigue. However, it may lead to severe patterns associated with multiple organ failure in individuals with an impaired immune system. OBJECTIVE: Here we report a 7-year-old girl with hyper-immunoglobulin M (IgM) (HIgM) phenotype, admitted to the hospital emergency department with fever, cough, and pneumonia symptoms because of the COVID-19 infection. Coronavirus infection was confirmed by a positive real-time polymerase chain reaction test. Surprisingly, serum levels of both IgG and IgA of the patient were transiently normalized during the COVID-19 infection when tested prior to the monthly injection of intravenous immunoglobulin. After she recovered from the COVID infection, her immunoglobulin levels returned to the primary stage and she demonstrated HIgM phenotype. CONCLUSION: Since this transient increase in the levels of immunoglobulins was solely observed during the COVID-19 infection, and no other infectious episodes were diagnosed in the patient, clarifying the exact cause would help to understand in a better manner the implications and specification of humoral immunity in patients with primary antibody deficiencies.

Cryptococcal Meningitis and Post-Infectious Inflammatory Response Syndrome in a Patient With X-Linked Hyper IgM Syndrome: A Case Report and Review of the Literature.

The hyper IgM syndromes are a rare group of primary immunodeficiency. The X-linked Hyper IgM syndrome (HIGM), due to a gene defect in CD40L, is the commonest variant; it is characterized by an increased susceptibility to a narrow spectrum of opportunistic infection. A few cases of HIGM patients with Cryptococcal meningoencephalitis (CM) have been described in the literature. Herein we report the case of a young male diagnosed in infancy with HIGM who developed CM complicated by a post-infectious inflammatory response syndrome (PIIRS), despite regular immunoglobulin replacement therapy and appropriate antimicrobial prophylaxis. The patient was admitted because of a headache and CM was diagnosed through detection of Cryptococcus neoformans in the cerebrospinal fluid. Despite the antifungal therapy resulting to negative CSF culture, the patient exhibited persistent headaches and developed diplopia. An analysis of inflammatory cytokines on CSF, as well as the brain MRI, suggested a diagnosis of PIIRS. Therefore, a prolonged corticosteroids therapy was started obtaining a complete resolution of symptoms without any relapse.

CD40LG mutations in Vietnamese patients with X-linked hyper-IgM syndrome; catastrophic anti-phospholipid syndrome as a new complication.

BACKGROUND: X-linked hyper-IgM syndrome (XHIGM) is a rare primary immunodeficiency caused by CD40 ligand defects. METHODS: We identified three patients with XHIGM in Ho Chi Minh City, Vietnam. Whole-exome sequencing, immunological analyses and western blot were performed to investigate phenotypic and genotypic features. RESULTS: Despite showing symptoms typical of XHIGM, including recurrent sinopulmonary infections, oral ulcers and otitis media, the diagnosis was significantly delayed. One patient developed anti-phospholipid syndrome, which has been documented for the first time in XHIGM syndrome. Two patients had elevated IgM levels and all of them had low IgG levels. Exome sequencing revealed mutations in the CD40LG gene: one novel splicing mutation c.156+2T>A and two previously characterised mutations (non-frameshift deletion c.436_438delTAC, stop-gain c.654C>A). Due to these mutations, the CD40 ligand was not expressed in any of the three patients, as demonstrated by western blot analysis. CONCLUSION: This is the first report of XHIGM syndrome in Vietnam indicates that an effective diagnostic strategy, such as sequencing analysis, contributes to reliable diagnosis and subsequent therapy.

Human Inborn Errors of Immunity (HIEI): predominantly antibody deficiencies (PADs): if you suspect it, you can detect it

Abstract Objective: This minireview gathers the scientific foundations of the literature on genetic errors in the development of the humoral immune system to help pediatricians suspect these defects. Sources: A systemic search using the PubMed MEDLINE database was performed for all Predominantly Antibody Deficiencies (PADs) described in the 2020 IUIS Expert Committee for PID classification system, combined with terms for hypogammaglobulinemia. Search terms for PADs were based on the listed names and affected genes as classified by the IUIS 2020. Abstracts of the results were reviewed to find relevant case series, review articles of PADs associated with infection, opportunistic infection, autoimmunity, cytopenias, malignancies, inflammatory diseases, neurological and respiratory diseases. References from relevant articles were further reviewed for additional references. Relevant findings were grouped in accordance with the IUIS 2020 classification system. Clinical and genetic features, if known, were described. Data synthesis: PADs refer to impaired antibody production due to molecular defects intrinsic to B cells or a failure of interaction between B and T cells. The patients develop recurrent or chronic infection or respond to the antigens with dysregulation of the immune function, causing severe allergy, autoimmunity, inflammation, lymphoproliferation and malignancy. The diagnosis is a combined exercise of clinical and laboratory investigation similar to that performed by Bruton (1952). In the context of SARS-CoV-2 infection, the experience of XLA and CVID patients has been surprising. Variants in 39 genes were reported as causing PADs, but the clinical heterogeneity within each variant is not clear. Conclusion: Bruton (1952) used clinical expertise and protein electrophoresis to identify XLA. The IUIS (2020) committee used immunoglobulins and B lymphocyte to characterize PADs. Pediatricians should suspect it to detect it and prevent morbidities that can have an astonishing and irreversible impact on the child's life.

Mitochondrial DNA insert into CD40 ligand gene-associated X-linked hyper-IgM syndrome.

BACKGROUND: X-linked hyper-IgM (X-HIGM), which results from mutations in the CD40LG gene located on chromosome Xq26.3, is the most common form of HIGM. To date, more than 130 variants of the CD40L gene have been reported. We described a patient with novel de novo nuclear mitochondrial DNA sequences (NUMTs) in the CD40LG gene that have resulted in X-HIGM. METHODS: Whole-exome sequencing (WES) analysis was used to screen for causal variants in the genome, and the candidate breakpoint was confirmed by Sanger sequencing. RESULTS: A new mutation of CD40LG, which deletes A at position 17 followed by a 147-nucleotide from mitochondrial DNA copies insertion in exon 1, was detected in a 20-month-old boy harbouring an X-HIGM combined with immunodeficiency syndrome. CONCLUSION: This is one of the few cases of a human genetic disease caused by nuclear mitochondrial DNA sequences (NUMTs). The presented data serve to demonstrate that de novo NUMT transfer of nucleic acid is a novel mechanism of X-HIGM.

Modeling, optimization, and comparable efficacy of T cell and hematopoietic stem cell gene editing for treating hyper-IgM syndrome.

Precise correction of the CD40LG gene in T cells and hematopoietic stem/progenitor cells (HSPC) holds promise for treating X-linked hyper-IgM Syndrome (HIGM1), but its actual therapeutic potential remains elusive. Here, we developed a one-size-fits-all editing strategy for effective T-cell correction, selection, and depletion and investigated the therapeutic potential of T-cell and HSPC therapies in the HIGM1 mouse model. Edited patients' derived CD4 T cells restored physiologically regulated CD40L expression and contact-dependent B-cell helper function. Adoptive transfer of wild-type T cells into conditioned HIGM1 mice rescued antigen-specific IgG responses and protected mice from a disease-relevant pathogen. We then obtained ~ 25% CD40LG editing in long-term repopulating human HSPC. Transplanting such proportion of wild-type HSPC in HIGM1 mice rescued immune functions similarly to T-cell therapy. Overall, our findings suggest that autologous edited T cells can provide immediate and substantial benefits to HIGM1 patients and position T-cell ahead of HSPC gene therapy because of easier translation, lower safety concerns and potentially comparable clinical benefits.

Novel mutations in hyper-IgM syndrome type 2 and X-linked agammaglobulinemia detected in three patients with primary immunodeficiency disease.

BACKGROUND: Ambiguous or atypical phenotypes can make a definite diagnosis of primary immunodeficiency diseases based on biochemical indices alone challenging. Further, mortality in early life because of infections in patients with these conditions supports the use of genetic tests to facilitate rapid and accurate diagnoses. METHODS: Genetic and clinical analyses of three unrelated Chinese children with clinical manifestations of recurrent infections, who were considered to have primary immunodeficiency diseases, were conducted. Patient clinical features and serum immunological indices were recorded. Next-generation sequencing was used to screen for suspected pathogenic variants. Family co-segregation and in silico analysis were conducted to evaluate the pathogenicity of identified variants, following the American College of Medical Genetics and Genomics guidance. RESULTS: All three patients were found to have predominant antibody defects. Sequencing analysis revealed that one had two compound heterozygous variants, c.255C>A and c.295C>T, in the autosomal gene, activation-induced cytidine deaminase (AICDA). The other two patients were each hemizygous for the variants c.1185G>A and c.82C>T in the Bruton's tyrosine kinase (BTK) gene on the X chromosome. In silico analysis revealed that identified substituted amino acids were highly conserved and predicted to cause structural and functional damage to the proteins. CONCLUSION: Four pathogenic variants in AICDA and BTK were confirmed to cause different forms of hyper-IgM syndrome type 2 (HIGM2) and X-linked agammaglobulinemia (XLA); two were novel mutations that have never been reported previously. This is the first report of HIGM2 caused by AICDA deficiency in a patient from the Chinese mainland.

Effect of Class Switch Recombination Defect on the Phenotype of Ataxia-Telangiectasia Patients.

Objectives: Ataxia-telangiectasia (A-T) is an autosomal recessive neurodegenerative disorder with multisystem involvement caused by homozygous or compound heterozygous mutations in the ataxia telangiectasia mutated (ATM) gene which encodes a serine/threonine protein kinase. The aims of this study were to investigate class switch recombination (CSR) and to review the clinical and immunologic phenotypes of 3 groups of A-T patients, including A-T patients with CSR defects (CSR-D), A-T patients with selective immunoglobulin A deficiency (IgA-D) and A-T patients with normal Ig level. Methods: In this study, 41 patients with confirmed diagnosis of A-T (16 A-T patients with HIgM, 15 A-T patients with IgA-D, and 10 A-T patients with normal Ig levels) from Iranian immunodeficiency registry center were enrolled. B-cell proliferation, in vitro CSR toward IgE and IgA were compared between three groups as well as G2 radiosensitivity assay. Results: Earliest presentation of telangiectasia was a significant hallmark in A-T patients with CSR-D (p = .036). In this investigation, we found that the frequency of respiratory infection (p = .002), pneumonia (p = .02), otitis media (p = .008), chronic fever (p < .001), autoimmunity (p = .02) and hepatosplenomegaly (p = .03) in A-T patients with HIgM phenotype were significantly higher than the other groups. As expected IgE production stimulation and IgA CSR were perturbed in HIgM patients that were aligned with the higher readiosenstivity scores in this group. Conclusion: A-T patients with HIgM compared to other A-T patients presenting more infections and noninfectious complications, therefore, early detection and careful management of these patients is necessary.