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Summary: Biallelic pathogenic variants in CAD, that encode the multienzymatic protein required for de‐novo pyrimidine biosynthesis, cause early infantile epileptic encephalopathy‐50. This rare disease, characterized by developmental delay, intractable seizures and anaemia, is amenable to treatment with uridine. We present a patient with macrocytic anaemia, elevated haemoglobin‐A2 levels, anisocytosis, poikilocytosis and target cells in the blood smear, and mild developmental delay. A next‐generation sequencing panel revealed biallelic variants in CAD. Functional studies did not support complete abrogation of protein function; however, the patient responded to uridine supplement. We conclude that biallelic hypomorphic CAD variants may cause a primarily haematological phenotype. [ABSTRACT FROM AUTHOR]

Mutations affecting T-cell receptor (TCR) signaling typically cause combined immunodeficiency (CID) due to varying degrees of disturbed T-cell homeostasis and differentiation. Here, we describe two cousins with CID due to a novel nonsense mutation in LCK and investigate the effect of this novel nonsense mutation on TCR signaling, T-cell function, and differentiation. Patients underwent clinical, genetic, and immunological investigations. The effect was addressed in primary cells and LCK-deficient T-cell lines after expression of mutated LCK. Results: Both patients primarily presented with infections in early infancy. The LCK mutation led to reduced expression of a truncated LCK protein lacking a substantial part of the kinase domain and two critical regulatory tyrosine residues. T cells were oligoclonal, and especially naïve CD4 and CD8 T-cell counts were reduced, but regulatory and memory including circulating follicular helper T cells were less severely affected. A diagnostic hallmark of this immunodeficiency is the reduced surface expression of CD4. Despite severely impaired TCR signaling mTOR activation was partially preserved in patients’ T cells. LCK-deficient T-cell lines reconstituted with mutant LCK corroborated partially preserved signaling. Despite detectable differentiation of memory and effector T cells, their function was severely disturbed. NK cell cytotoxicity was unaffected. Residual TCR signaling in LCK deficiency allows for reduced, but detectable T-cell differentiation, while T-cell function is severely disturbed. Our findings expand the previous report on one single patient on the central role of LCK in human T-cell development and function. [ABSTRACT FROM AUTHOR]

Hematopoietic stem-cell transplantation (HSCT) is the only curative treatment for chronic granulomatous disease (CGD) and leukocyte-adhesion deficiency (LAD), but both diseases have high rates of graft failure in transplant and patients with these diseases are often referred to HSCT with significant comorbidity. The intensity of the conditioning regimen should be balanced between the need to ensure durable engraftment and to minimize toxicity when transplanting young children with infections and organ damage. We report on 26 children transplanted at our institution with CGD and LAD over 24 years. We found a higher incidence of graft failure in patients receiving treosulfan based conditioning for their first transplant. There was no effect of conditioning regimen on overall survival, as all 8 patients that proceeded to a second busulfan-based HSCT were salvaged. We recommend giving patients with CGD and LAD fully myeloablative conditioning with either a busulfan-based regimen or the combination of treosulfan, fludarabine, and thiotepa. [ABSTRACT FROM AUTHOR]

We describe the first cases of germline biallelic null mutations in ARPC5, part of the Arp2/3 actin nucleator complex, in two unrelated patients presenting with recurrent and severe infections, early-onset autoimmunity, inflammation, and dysmorphisms. This defect compromises multiple cell lineages and functions, and when protein expression is reestablished in-vitro, the Arp2/3 complex conformation and functions are rescued. As part of the pathophysiological evaluation, we also show that interleukin (IL)−6 signaling is distinctively impacted in this syndrome. Disruption of IL-6 classical but not trans-signaling highlights their differential roles in the disease and offers perspectives for therapeutic molecular targets. Mutations that impact the function of the Arp2/3 complex are known to cause inborn errors of immunity. Here the authors describe biallelic null mutations in the ARPC5 subunit of Arp2/3 that disrupt actin function and cytokine signaling, causing infections, autoimmunity, inflammation and dysmorphisms. [ABSTRACT FROM AUTHOR]

Increased susceptibility to develop severe forms of Epstein-Barr virus (EBV) infection in early age is a significant hallmark of an underlying primary immunodeficiency (PID). Here, we present immunologic and genetic evaluations of a 3-year-old child who was born to first-cousins parents and presented with recurrent infections, failure to thrive, and severe EBV-related infection and proliferation. A diagnosis of diffuse large B cell lymphoma was made and the immunological workup was suggestive of T cell immunodeficiency. Unfortunately, the patient succumbed to EBV-related lymphoma. Whole-exome sequencing revealed a novel homozygous mutation, c.991del.C; p. Q331Sfs*6 in the SLP76 gene. The SLP76 protein, a TCR signaling molecule, was recently linked to a human disease of the immune system. In order to examine the effect of this new SLP76 mutation on T cell signaling, a SLP76-deficient Jurkat-derived T cell line was transduced either with wild-type (WT), or with the specific SLP76 mutant, or with a mock vector. Downstream TCR signaling events, including ERK1/2 phosphorylation, CD69 expression, and Ca2 + mobilization, were reduced in cells harboring the reported mutation, linking this novel mutation to the expected immunological outcome. SLP76 deficiency should be added to the growing list of monogenetic diseases that predispose affected individuals to acquire severe and uncontrolled EBV infections and to develop substantial complications. This case further links mutations in the SLP76 gene to a significant human immunodeficiency and extends its clinical phenotype. [ABSTRACT FROM AUTHOR]

Purpose: Patients with X-linked agammaglobulinemia (XLA) are characterized by humoral impairment and are routinely treated with intravenous immunoglobulin (IVIG). In this study, we aimed to investigate the presence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies in IVIG preparations harvested globally and evaluate the transfer of SARS-CoV-2 antibodies to the XLA patient. Methods: A single-center, prospective cohort study was conducted in the period of November 2020 to November 2022. Clinical and laboratory data, specifically, SARS-CoV-2 spike IgG levels from the serum of 115 IVIG preparations given to 5 XLA patient were collected. Concurrently, SARS-CoV-2 spike IgG levels from the serum of the 5 XLA was collected monthly. Results: Five XLA patients were evaluated within the study period. All were treated monthly with commercial IVIG preparations. A total of 115 IVIG treatments were given over the study period. The origin country and the date of IVIG harvesting was obtained for 111 (96%) of the treatments. Fifty-four IVIG preparations (49%) were harvested during the COVID-19 pandemic of which 76% were positive (>50AU/mL) for SARS-CoV-2 spike antibodies which were subsequently transmitted to the XLA patients in an approximate 10-fold reduction. SARS-CoV2 spike IgG was first detected in IVIG batches that completed their harvest date by September 2021. Positive products were harvested from origin countries with a documented prevalence over 2,000 per 100,000 population. Conclusion: As the prevalence of COVID-19 infections rises, detection of SARS-CoV-2 spike IgG in commercial IVIG products increases and is then transmitted to the patient. Future studies are needed to investigate the neutralizing capabilities of SARS-CoV-2 IgG and whether titer levels in IVIG remain consistent as the incidence of infection and vaccination rates in the population changes. [ABSTRACT FROM AUTHOR]

This document, titled "Perspective - Was it All for Nothing?" is a letter published in the Journal of Clinical Immunology. The author, Dr. Raz Somech, is an Israeli pediatrician specializing in genetic diseases of the immune system. He discusses his experiences treating Palestinian children with inborn errors of immunity, emphasizing the importance of treating everyone with respect and compassion. He also mentions a documentary called "Precious Life" that highlights the struggle to save the life of a sick Palestinian baby. Dr. Somech expresses his sadness and questions the bridges of coexistence that have been built in light of a brutal attack on his country by terrorists from the Gaza Strip. Despite this, he believes that doctors should continue to treat everyone and convey a message of peace and friendship. He concludes by stating that medicine can make life better, not just healthier. [Extracted from the article]

Patients with Wiskott-Aldrich syndrome (WAS) harbor mutations in the WAS gene and suffer from immunodeficiency, microthrombocytopenia, and eczema. T-cells play an important role in immune response in the skin and the γδT-cells have an important role in skin homeostasis. Since WAS patients often present with eczema, we wanted to examine whether the T-cell receptor gamma (TRG) repertoire of the γδT-cells is affected in these patients. In addition, the immunoglobulin heavy chain (IGH) repertoire from genomic DNA of WAS patients was not yet studied. Thus, we sought to determine the effects that specific WAS mutations from our patients have in shaping the TRG and IGH immune repertoires. We collected clinical and genetic data on four WAS patients, each harboring a different mutation in the WAS gene. Using next-generation sequencing (NGS), we analyzed their TRG and IGH repertoires using genomic DNA isolated from their peripheral blood. We analyzed the TRG and IGH repertoire sequences to show repertoire restriction, clonal expansions, preferential utilization of specific V genes, and unique characteristics of the antigen binding region in WAS patients with eczema compared to healthy controls. Both the TRG and IGH repertoire showed diverse repertoire comparable to healthy controls on one the hand, and on the other hand, the IGH repertoire showed increased diversity, more evenly distributed repertoire and immaturity of the antigen binding region. Thus, we demonstrate by analyzing the repertoire based on genomic DNA, the various effect that WAS mutations have in shaping the TRG and IGH adaptive immune repertoires. [ABSTRACT FROM AUTHOR]

Purpose: Receptor-interacting serine/threonine-protein kinase 1 (RIPK1) is an important regulator of necroptosis and inflammatory responses. We present the clinical features, genetic analysis and immune work-up of two patients with infantile-onset inflammatory bowel disease (IBD) resulting from RIPK1 mutations. Methods: Whole exome and Sanger sequencing was performed in two IBD patients. Mass cytometry time of flight (CyTOF) was conducted for in-depth immunophenotyping on one of the patient's peripheral blood mononuclear cells, and compared to control subjects and patients with Crohn's disease. Results: The patients presented with severe colitis and perianal fistulas in the first months of life, without severe/atypical infections. Genetic studies identified pathogenic genetic variants in RIPK1 (Patient 1, A c.1934C>T missense mutation in Exon 11; Patient 2, c.580G>A missense mutation residing in Exon 4). Protein modeling demonstrated that the mutation in Patient 1 displaces a water molecule, potentially disrupting the local environment, and the mutation in Patient 2 may lead to disruption of the packing and conformation of the kinase domain. Immunofluorescence RIPK1 staining in rectal biopsies demonstrated no expression for Patient 1 and minimal expression for Patient 2, compared to controls and patients with active Crohn's disease. Using CyTOF unbiased clustering analysis, we identified peripheral immune dysregulation in one of these patients, characterized by an increase in IFNg CD8+ T cells along with a decrease in monocytes, dendritic cells and B cells. Moreover, RIPK1-deficient patient's immune cells exhibited decreased IL-6 production in response to lipopolysaccharide (LPS) across multiple cell types including T cells, B cells and innate immune cells. Conclusions: Mutations in RIPK1 should be considered in very young patients presenting with colitis and perianal fistulas. Given RIPK1's role in inflammasome activation, but also in epithelial cells, it is unclear whether IL1 blockade or allogeneic hematopoietic stem cell transplantation can suppress or cure the hyper-inflammatory response in these patients. Additional studies in humans are required to better define the role of RIPK1 in regulating intestinal immune responses, and how treatment can be optimized for patients with RIPK1 deficiency. [ABSTRACT FROM AUTHOR]

The International Union of Immunological Societies (IUIS) expert committee (EC) on Inborn Errors of Immunity (IEI) reports here the 2022 updated phenotypic classification, which accompanies and complements the most-recent genotypic classification. This phenotypic classification is aimed for clinicians at the bedside and focuses on clinical features and laboratory phenotypes of specific IEI. In this classification, 485 IEI underlying phenotypes as diverse as infection, malignancy, allergy, auto-immunity and auto-inflammation are described, including 55 novel monogenic defects and 1 autoimmune phenocopy. Therefore, all 485 diseases of the genetic classification are presented in this paper in the form of colored tables with essential clinical or immunological phenotype entries. [ABSTRACT FROM AUTHOR]

We report the updated classification of inborn errors of immunity, compiled by the International Union of Immunological Societies Expert Committee. This report documents the key clinical and laboratory features of 55 novel monogenic gene defects, and 1 phenocopy due to autoantibodies, that have either been discovered since the previous update (published January 2020) or were characterized earlier but have since been confirmed or expanded in subsequent studies. While variants in additional genes associated with immune diseases have been reported in the literature, this update includes only those that the committee assessed that reached the necessary threshold to represent novel inborn errors of immunity. There are now a total of 485 inborn errors of immunity. These advances in discovering the genetic causes of human immune diseases continue to significantly further our understanding of molecular, cellular, and immunological mechanisms of disease pathogenesis, thereby simultaneously enhancing immunological knowledge and improving patient diagnosis and management. This report is designed to serve as a resource for immunologists and geneticists pursuing the molecular diagnosis of individuals with heritable immunological disorders and for the scientific dissection of cellular and molecular mechanisms underlying monogenic and related human immune diseases. [ABSTRACT FROM AUTHOR]

The transcription factor GATA2 plays a key role in the survival and self-renewal of hematopoietic stem and progenitor cells. Autosomal dominant variants in GATA2 cause a broad spectrum of heterogeneous phenotypes. Here, we present our experience with GATA2 deficiency in a retrospective multicenter analysis of computerized medical records of adult patients (age ≥18 years) treated between 2018 and 2022 at Shaare Zedek Medical Center in Jerusalem and Sheba Tel-Hashomer Medical Center in Ramat Gan, Israel. Two male and two female patients with GATA2 deficiency were identified. Three of the patients presented with symptoms in adult life and all patients were diagnosed as adults. Age at presentation was 10.5-36 years and age at diagnosis 24-47 years. Diagnosis was delayed in all patients by 1-24.5 years. The phenotypic diversity was notable. Patients presented with myelodysplastic syndrome (n=2), pulmonary alveolar proteinosis (n=1), and recurrent viral (n=1), bacterial (n=3), and mycobacterial (n=1) infections. Bone marrow biopsy revealed cytogenetic abnormalities in one patient (monosomy 7). Patients were diagnosed by exome sequencing (n=3) and Sanger sequencing of the coding exons in GATA2 (n=1). Novel heterozygous GATA2 variants (c.177C>A, p.Y59* and c.610dup, p.R204Pfs*78) were identified in two patients. Immune workup revealed B cell lymphopenia and monocytopenia in all tested patients. One patient died from overwhelming sepsis despite all patients being treated with antibiotics and anti-mycobacterials. Our cohort highlights the phenotypic diversity, late presentation, and delayed diagnosis of GATA2 deficiency. Increased awareness of this primary immune deficiency presenting in adult life is needed and should involve a high index of suspicion. [ABSTRACT FROM AUTHOR]

Diagnosis of primary complement deficiencies requires a high index of suspicion. Thus, susceptible patients are often underdiagnosed and untreated. Here, we present a multicenter experience with two novel inborn errors of the classical complement system. This is a retrospective multicenter analysis of computerized medical records of children (<18 years) admitted in the period between 2012 and 2018 at Shaare Zedek Medical Center in Jerusalem and Edmond and Lily Safra Children's Hospital, Tel-Hashomer Medical Center, in Ramat Gan, Israel. Patients were genetically diagnosed by a complementary immune workup. We identified 5 patients (3 males) from four different families harboring two novel mutations in the complement components C6–C8. Genetic mutations were identified by whole-exome sequencing or by sequencing of the coding exons of a single gene based on the findings in the immune workup. Clinical manifestations consisted of meningitis with or without meningococcemia. The immune workup demonstrated nearly absent levels of CH50, compatible with a complement pathway defect. Diagnosis delay ranged between 0 and 30 years. Conclusion: Awareness of risk factors for primary complement deficiencies, even at the first infectious episode, should facilitate prompt immune and genetic workup, commencing diagnosis and proper treatment for the patient and family. What is Known: • Deficiencies in the classical terminal complement components increase susceptibility to invasive meningococcal infections. • Recurrent meningococcal infections mandate a diagnostic workup of the complement system. What is New: • Genetic workup can be utilized for prompt diagnosis of complement deficiencies. • High rates of consanguinity, even in the presence of a single meningococcal infection, should promote immune and genetic workups. [ABSTRACT FROM AUTHOR]

We received 223 patient reports on attacks, with 92% experiencing a prodrome before at least one attack, and 64% said they are able to predict an oncoming attack by a prodrome. Keywords: attacks; dimensions; domains; hereditary angioedema; prodromes EN attacks dimensions domains hereditary angioedema prodromes 1309 1312 4 03/30/22 20220401 NES 220401 ACKNOWLEDGMENTS We thank our colleagues from other HAE centers in Israel and the Israeli HAE patient organization (EDEMA) for their collaboration. Orange bars = attacks, blue bars = prodromes gl These results indicate that HAE patients can distinguish prodromes from attacks and that prodromes foretell subsequent attack location and intensity. [Extracted from the article]

X-linked agammaglobulinemia (XLA) is caused by mutations in the Bruton tyrosine kinase) BTK) gene. Affected patients have severely reduced amounts of circulating B cells. Patients with atypical XLA may have residual circulating B cells, and there are few studies exploring these cells' repertoire. We aimed to study the B cell repertoire of a novel hypomorphic mutation in the BTK gene, using the next generation sequencing (NGS) technology. Clinical data was collected from our clinical records. Real-time PCR was used to determine KREC copies, and NGS was used to determine the immunoglobulin (Ig) heavy chain (IgH) repertoire diversity. Both patients had a relatively mild clinical and laboratory phenotype, residual BTK protein expression, and the same novel mutation in the BTK gene, c.1841 T > C, p. L614P. Signal-joint kappa-deleting recombination excision circles (sj-KREC) for both patients were completely absent reflecting lack of naïve B cells. The intron RSS-Kde coding joints (cj) were significantly reduced, reflecting residual replicating B cells. NGS displayed restricted IgH repertoire with highly uneven distribution of clones, especially for Pt2. We report a novel BTK mutation, c.1841 T > C (p. L614P) that is associated with a relatively mild phenotype. We conclude that the IgH repertoire in atypical XLA is restricted with highly uneven distribution of clones. This phenomenon may be explained by extremely reduced to non-existent levels of BTK in B cells. This report sheds further light on atypical cases of XLA. [ABSTRACT FROM AUTHOR]

Background: Kabuki syndrome (KS) is a genetic disorder caused mainly by de novo pathogenic variants in KMT2D or KDM6A, characterized by recognizable facial features, intellectual disability, and multi-systemic involvement, including short stature, microcephaly, hearing loss, cardiac defects, and additional congenital anomalies. While congenital anomalies of the kidneys and urinary tract (CAKUT) are known manifestations of this disorder, studies focused solely on kidney involvement are scarce, and its prevalence is most likely underestimated. This study aimed to describe the prevalence and nature of CAKUT and other renal manifestations, in a cohort of KS patients followed at a single tertiary center. Methods: All patients who were evaluated at the Sheba Medical Center and received a clinical and/or molecular diagnosis of KS, over a 16-year period (2004–2020), were included. Digital medical records, including ultrasound studies, were reviewed by a team of pediatric nephrologists. Results: Thirteen patients were included in the study, at ages ranging from the neonatal period to 20 years. In eight patients, a pathogenic variant in KMT2D was established. CAKUT were detected in 8/13 (61.5%) of patients and varied from hypospadias, hydronephrosis, or double collecting systems to pelvic kidney, kidney asymmetry, horseshoe kidney, or kidney agenesis. One patient experienced kidney failure necessitating transplantation at 20 years of age. Conclusions: Our findings underscore the high prevalence of CAKUT and genitourinary involvement in patients with KS and suggest that assessment by pediatric nephrology specialists is warranted as part of the routine multidisciplinary evaluation of newly diagnosed patients. A higher resolution version of the Graphical abstract is available as Supplementary information [ABSTRACT FROM AUTHOR]

Signal transducer and activator of transcription (STAT)1 heterozygous gain‐of‐function (GOF) mutations are known to induce immune dysregulation and chronic mucocutaneous candidiasis (CMCC). Previous reports suggest an association between demodicosis and STAT1 GOF. However, immune characterization of these patients is lacking. Here, we present a retrospective analysis of patients with immune dysregulation and STAT1 GOF who presented with facial and ocular demodicosis. In‐depth immune phenotyping and functional studies were used to characterize the patients. We identified five patients (three males) from two non‐consanguineous Jewish families. The mean age at presentation was 11.11 (range = 0.58–24) years. Clinical presentation included CMCC, chronic demodicosis and immune dysregulation in all patients. Whole‐exome and Sanger sequencing revealed a novel heterozygous c.1386C>A; p.S462R STAT1 GOF mutation in four of the five patients. Immunophenotyping demonstrated increased phosphorylated signal transducer and activator of transcription in response to interferon‐α stimuli in all patients. The patients also exhibited decreased T cell proliferation capacity and low counts of interleukin‐17‐producing T cells, as well as low forkhead box protein 3+ regulatory T cells. Specific antibody deficiency was noted in one patient. Treatment for demodicosis included topical ivermectin and metronidazole. Demodicosis may indicate an underlying primary immune deficiency and can be found in patients with STAT1 GOF. Thus, the management of patients with chronic demodicosis should include an immunogenetic evaluation. [ABSTRACT FROM AUTHOR]

Background: Cutaneous manifestations of dedicator of cytokinesis 8 gene (DOCK8) deficiency, a combined type of T and B cell immunodeficiency, previously designated as autosomal recessive hyper IgE syndrome, includes dermatitis and skin infections. There are limited treatment options for dermatitis related to the syndrome. Objective: To describe a cohort of patients with DOCK8 deficiency with a focus on the treatment of their cutaneous manifestations. Methods: A retrospective study on all children with the genetic diagnosis of DOCK8 deficiency treated at the Sheba Medical Center between 1/1/2003 and 1/1/2021 was preformed. Collected data included: demographic features, family history, laboratory, genetic testing, skin manifestations, treatment, and disease course. Description of two cases of severe recalcitrant dermatitis treated with dupilumab is detailed. Results: Nine children with a genetic diagnosis of DOCK8 deficiency were included, of whom six were girls (66%) with a median age of 8.5 (±2.2 SD) years. The median age at diagnosis was 2.8 (±2.6 SD) years. Six patients were born to consanguineous parents. Five out of six patients who received hematopoietic stem cell transplantation (HSCT) had a complete response, and one was recently transplanted. Of note, two patients, while awaiting HSCT, were treated with dupilumab for their severe dermatitis resulting in a marked improvement of the cutaneous manifestations and pruritus. Conclusions: Hematopoietic stem cell transplantation is the gold standard and most effective therapy for patients with DOCK8 deficiency. Dupilumab, a biological therapy indicated for atopic dermatitis and other Th2 derived dermatoses, is an excellent option for dermatitis in patients with DOCK8 deficiency and can be used as a bridge before HSCT. Larger studies are needed to confirm this observation. [ABSTRACT FROM AUTHOR]

A disease-specific, patient-reported outcome instrument suitable for evaluation of prodromes and attacks of hereditary angioedema (HAE) is a clinical unmet need. We constructed such instrument and examined its validity, acceptability, and discriminative ability. Sixty-six patients participated in a survey addressing their demographics, social, and medical status. Discriminant content validity involved: (1) construct definition by in-depth cognitive debriefing interviews, (2) item selection identifying relevant categories, and (3) judgment of the format whereby questionnaires were tested on experienced patients and its content/reliability was validated. Prodromes and attacks affecting certain body systems (domains) were organized in "clusters". Internal consistency, content, and convergent validities were analyzed. Analyses of variance and regression models were used to evaluate the discriminative ability of the instrument to differentiate between attacks and prodromes. The study demonstrates very high internal consistency (Cronbach's α: attacks 0.88–0.98, prodromes 0.78–0.98). Analysis of variance confirmed significant differences between all dimensions and in pre-defined clusters (F (4, 61) = 45.74, p < 0.001, Eta2 = 0.77). Significant correlations were found between dimensions of prodromes and attacks. Prodromes are associated but differentiated from attacks. Correlations in severity were high for all domains. Interactions were found between prodromes and patients' experience in illness. In conclusion, the new Prodrome-Attack Evaluation questionnaire (HAE-EPA) is capable of distinguishing attacks and prodromes of HAE, as well as determining associations between the two interrelated phenomena. The new instrument achieves the required discriminative ability, acceptability, and content validity/reliability and therefore can be used as a reliable tool for the investigation of prodromes, attacks, and their relationships. [ABSTRACT FROM AUTHOR]

The most recent updated classification of inborn errors of immunity/primary immunodeficiencies, compiled by the International Union of Immunological Societies Expert Committee, was published in January 2020. Within days of completing this report, it was already out of date, evidenced by the frequent publication of genetic variants proposed to cause novel inborn errors of immunity. As the next formal report from the IUIS Expert Committee will not be published until 2022, we felt it important to provide the community with a brief update of recent contributions to the field of inborn errors of immunity. Herein, we highlight studies that have identified 26 additional monogenic gene defects that reach the threshold to represent novel causes of immune defects. [ABSTRACT FROM AUTHOR]

Genetic diagnostic tools including whole-exome sequencing (WES) have advanced our understanding in human diseases and become common practice in diagnosing patients with suspected primary immune deficiencies. Establishing a genetic diagnosis is of paramount importance for tailoring adequate therapeutic regimens, including identifying the need for hematopoietic stem cell transplantation (HSCT) and genetic-based therapies. Here, we genetically studied two adult patients who were clinically diagnosed during infancy with severe combined immune deficiency (SCID). Two unrelated patients, both of consanguineous kindred, underwent WES in adulthood, 2 decades after their initial clinical manifestations. Upon clinical presentation, immunological workup was performed, which led to a diagnosis of SCID. The patients presented during infancy with failure to thrive, generalized erythematous rash, and recurrent gastrointestinal and respiratory tract infections, including episodes of Pneumocystis pneumonia infection and Candida albicans fungemia. Hypogammaglobulinemia and T-cell lymphopenia were detected. Both patients were treated with a 10/10 HLA matched sibling donor unconditioned HSCT. Retrospective genetic workup revealed homozygous bi-allelic mutations in IL7RA in one patient and in RAG2 in the other. Our study exemplifies the impact of retrospectively establishing a genetic diagnosis. Pinpointing the genetic cause raises several issues including optimized surveillance and treatment, understanding disease mechanisms and outcomes, future family planning, and social and psychological considerations. [ABSTRACT FROM AUTHOR]

Biallelic mutations in the zeta-associated protein 70 (ZAP70) gene cause combined immunodeficiency (CID). Neonatal screening for severe CID in Israel is implemented since 2015. We report on clinical, flow cytometry, and genetic data of an unusual ZAP70 deficiency patient. A 10-week-old Bedouin female presented with severe autoimmune hemolytic anemia. Cytomegalovirus (CMV) negative packed cell therapy was given without improvement; indexes of hemolysis worsened. At this time, thrombocytopenia was noted. The patient was treated with single dose of 1 g/kg intravenous immunoglobulin with rapid resolution of hemolysis. Serum immunoglobulin concentrations were normal; flow cytometry revealed severe CD8 lymphocytopenia. Lymphocyte proliferation test demonstrated reduced response to concanavalin A and phytohemagglutinin. Gated T cells were negative for intracellular ZAP70. A genetic analysis revealed a missense homozygous c.1388C > T (p.A463V) mutation, confirming the diagnosis of ZAP70 deficiency. She later on developed urinary tract infection due to ESBL producing E. coli treated with amikacin and severe CMV infection that partially responded to ganciclovir therapy and at 7 months of age, she successfully underwent allogeneic hematopoietic stem cell transplantation. Neonatal screening by T cell receptor excision circles (TRECs) for SCID was normal, yet very low TRECs were recorded at the time of CID diagnosis. Normal neonatal screening for SCID does not rule out the diagnosis of CID due to ZAP70 deficiency. This type of CID can present with autoimmunity as the sole initial manifestation of the disease. [ABSTRACT FROM AUTHOR]

Purpose: More than 50 different monogenic disorders causing inflammatory bowel disease (IBD) have been identified. Our goal was to characterize the clinical phenotype, genetic workup, and immunologic alterations in an Ashkenazi Jewish patient that presented during infancy with ulcerative colitis and unique clinical manifestations. Methods: Immune workup and whole-exome sequencing were performed, along with Sanger sequencing for confirmation. Next-generation sequencing of the TCRB and IgH was conducted for immune repertoire analysis. Telomere length was evaluated by in-gel hybridization assay. Mass cytometry was performed on patient's peripheral blood mononuclear cells, and compared with control subjects and patients with UC. Results: The patient presented in infancy with failure to thrive and dysmorphic features, consistent with a diagnosis of dyskeratosis congenita and Hoyeraal-Hreidarsson syndrome. Severe ulcerative colitis manifested in the first year of life and proceeded to the development of a primary immunodeficiency, presenting as Pneumocystis jiroveci pneumonia and hypogammaglobulinemia. Genetic studies identified a deleterious homozygous C.3791G>A missense mutation in the helicase regulator of telomere elongation 1 (RTEL1), leading to short telomeres in the index patient. Immune repertoire studies showed polyclonal T and B cell receptor distribution, while mass cytometry analysis demonstrated marked immunological alterations, including a predominance of naïve T cells, paucity of B cells, and a decrease in various innate immune subsets. Conclusions: RTEL1 mutations are associated with significant alterations in immune landscape and can manifest with infantile-onset IBD. A high index of suspicion is required in Ashkenazi Jewish families where the carriage rate of the C.3791G>A variant is high. [ABSTRACT FROM AUTHOR]

Background: More than 50 different monogenic disorders have been identified as directly causing inflammatory bowel diseases, typically manifesting in the first years of life. We present the clinical course and immunological work-up of an adult patient who presented in adolescent years with an atypical gastrointestinal phenotype and was diagnosed more than two decades later with a monogenic disorder with important therapeutic implications. Methods: Whole exome sequencing was performed in a 37-years-old patient with a history of diarrhea since adolescence. Sanger sequencing was used to validate the suspected variant. Mass cytometry (CyTOF) and flow cytometry were conducted on peripheral blood mononuclear cells for deep immunophenotyping. Next-generation sequencing of the TCRB and IgH was performed for global immune repertoire analysis of circulating lymphocytes. Results: We identified a novel deleterious c.1455C>A (p.Y485X) mutation in LRBA. CyTOF studies demonstrated significant changes in immune landscape in the LRBA-deficient patient, including an increase in myeloid derived suppressor cells and double-negative T cells, decreased B cells, low ratio of naïve:memory T cells, and reduced capacity of T cells to secrete various cytokines following stimulation, including tumor necrosis factor alpha (TNF-α) and interferon gamma (IFN-γ). In addition, this patient exhibited low frequency of regulatory T cells, with a reduction in their CTLA4 expression and interleukin (IL)-10 secretion. Finally, we show marked oligoclonal expansion of specific B- and T-cell clones in the peripheral blood of the LRBA-deficient patient. Conclusions: LRBA deficiency is characterized by marked immunological changes in innate and adaptive immune cells. This case highlights the importance of advanced genetic studies in patients with a unique phenotype, regardless of their age at presentation. [ABSTRACT FROM AUTHOR]

Patients with loss-of-function mutations in IL10 or IL10 receptor (IL10R) genes develop severe, medical-refractory, infantile-onset inflammatory bowel disease (IBD). We have previously reported significant alterations in innate and adaptive immune responses in these patients. Next generation sequencing platforms enable a comprehensive assessment of T cell receptor (TCR) and B cell receptor (BCR) repertoire patterns. We aimed to characterize TCR and BCR features in peripheral blood of patients with deleterious IL10 signaling defects. DNA was isolated from blood of seven patients with IL10R mutations and one with an IL10 mutation, along with eight controls, and subjected to next generation sequencing of TRB and IgH loci. A significant increase in clonality was observed in both TCR and BCR repertoires in circulating lymphocytes of IL10/IL10R-deficient patients, but to a much greater extent in T cells. Furthermore, short CDR3β length and altered hydrophobicity were demonstrated in T cells of patients, but not in B cells, secondary to lower rates of insertions of nucleotides, but not deletions, at the V-, D-, or J-junctions. We were unable to observe specific T or B clones that were limited only to the patients or among controls. Moreover, the expanded T cells clones were unique to each patient. In conclusion, next generation sequencing of the TCR and BCR is a powerful tool for characterizing the adaptive immune cell phenotype and function in immune-mediated disorders. The oligoclonality observed among IL10/IL10R-deficient patients may suggest specialization of unique clones that likely have a role in mediating tissue damage. Nevertheless, the lack of shared clones between patients provides another piece of evidence that the adaptive immune response in IBD is not triggered against common antigens. Additional studies are required to define the specific antigens that interact with the expanded IL10/IL10R-deficient clones. [ABSTRACT FROM AUTHOR]

Introduction: Severe combined immunodeficiency (SCID) is a fatal disorder resulting from various genetic defects. In the Middle East, where consanguineous marriage is prevalent, autosomal recessive mutations in recombination-activating genes (RAG) are a leading cause of SCID. We present a large cohort of SCID patients due to RAG1 or RAG2 mutations. Methods: Twenty-six patients with RAG1 or RAG2 deficiency, diagnosed at Sheba Medical Center, were retrospectively investigated. Clinical presentation, immunologic phenotype, genetic analysis, treatment, and outcome were analyzed. Results: Majority of patients were referred from the Palestinian Authority. Most patients were males of Muslim Arab descent, 77% were born to consanguineous parents, and 65% had family history of immunodeficiency. Nearly all patients suffered from various infections before turning 2 months old, eight patients (31%) presented with Omenn and Omenn-like syndrome, and three patients (11%) had maternal engraftment. Notably, seven patients (27%) suffered from vaccine-derived infections, including a rare case of measles encephalitis. Nineteen patients underwent hematopoietic stem cell transplantation (HSCT) at a median age of 6 months, with a successful outcome for 72% of them. Genetic analysis revealed 11 different mutations (7 RAG2, 4 RAG1), two of them novel. Conclusions: Consanguineous marriages account for a genetic "founder effect." SCID is a pediatric emergency that dictates immediate precautions and curative treatment with HSCT. Due to lack of newborn screening for SCID within the Palestinian population, most patients in this cohort were diagnosed upon clinical symptoms, which led to a delayed diagnosis, harmful administration of contra-indicated live vaccines, delay in HSCT, and poor outcome. [ABSTRACT FROM AUTHOR]

Background: Bacille Calmette-Guerin (BCG) is included in the routine vaccination program in Gaza and the West Bank. Although safe, complications can occur and include local, extra-regional and disseminated BCG infection. Therefore it is contraindicated in immunodeficiencies. However, most infants are immunized prior to diagnosis of immunodeficiency. We report clinical and immunological characteristics of patients referred with severe combined immunodeficiency (SCID) who suffered from BCG complications. Methods: Files of patients referred for evaluation of immunodeficiency from January 2008 to February 2016 were retrieved. All patients have received BCG. Cell surface markers of peripheral blood mononuclear cells (PBMCs) were measured by immunofluorescent staining and flow cytometry. Serum concentrations of immunoglobulins were measured using nephelometry. Genetic diagnosis of SCID was made by direct Sanger sequencing of candidate genes. BCG complications were classified as: a) local; b) regional; c) distant; and d) disseminated disease. Results: Twenty-one children were diagnosed with SCID. BCG complications were diagnosed in 12 (57.1%). Eight patients developed local and regional disease (67%) and 4 (33%) had disseminated infection. Patients received at least three drugs: isoniazid, ethambutol and rifampicin. Outcome was relatively favorable with eight patients surviving (66.6%). No death related to BCG infection was observed. Disseminated disease was associated with reduced numbers of total lymphocytes, CD3 and CD8 levels (p <.05). Conclusions: Although high rates of BCG complications were observed, mortality was not increased and outcomes were good. Increased awareness in countries where BCG vaccine is not routinely administered and newborn screening programs for SCID could reduce complication rates. [ABSTRACT FROM AUTHOR]

The alpha subunit of IL-7 receptor (IL7R7α) is critical for the differentiation of T cells, specifically for the development and maintenance of γδT cells. Mutations in IL7RA are associated with Severe Combined Immunodeficiency (SCID). Infants with IL7RA deficiency can be identified through newborn screening program. We aimed at defining the immunological and genetic parameters that are directly affected by the IL7RA mutation on the immune system of five unrelated patients which were identified by our newborn screening program for SCID. The patients were found to have a novel identical homozygote mutation in IL7RA (n.c.120 C>G; p.F40L). Both surface expression of IL7Rα and functionality of IL-7 signaling were impaired in patients compared to controls. Structural modeling demonstrated instability of the protein structure due to the mutation. Lastly the TRG immune repertoire of the patients showed reduced diversity, increased clonality and differential CDR3 characteristics. Interestingly, the patients displayed significant different clinical outcome with two displaying severe clinical picture of immunodeficiency and three had spontaneous recovery. Our data supports that the presented IL7RA mutation affects the IL-7 signaling and shaping of the TRG repertoire, reinforcing the role of IL7RA in the immune system, while non-genetic factors may exist that attribute to the ultimate clinical presentation and disease progression. [ABSTRACT FROM AUTHOR]

Allogeneic hematopoietic stem cell transplantation (HSCT) is the effective mean of immune restoration in severe combined immunodefiency (SCID). Usually, HSCT without cytoreductive conditioning is attempted. Nevertheless, conditioning procedures are still preferred in a subset of patients. Herein, we describe the immunological outcome in a cohort of conditioned and unconditioned patients, from diagnosis, through transplantation, to follow-up. This retrospective study was conducted on 17 patients with SCID (10 conditioned, 7 unconditioned) who later underwent HSCT. Immune reconstitution was assessed in the post-transplant year by quantification of T cell receptor excision circles (TRECs) and kappa-deleting recombination excision circles (KRECs), among additional laboratory and clinical evaluations. Unconditioned patients were diagnosed and transplanted earlier. TREC and KREC quantification showed a gradual increase in both groups, with higher levels in the conditioned group. Engraftment percentages differed drastically between groups, favoring the conditioned group. Unconditioned patients were significantly more dependent on intravenous immunoglobulins (IVIGs). One patient from each group succumbed to disease complications. Conditioning demonstrated superior laboratorial outcomes. Patients with unique characteristics (i.e., consanguinity, Bacillus Calmette–Guérin vaccination, impaired access to IVIG) may require personalized considerations. The effort to implement secondary prevention of SCID with newborn screening should continue. [ABSTRACT FROM AUTHOR]

MALT1 (mucosa-associated lymphoid tissue lymphoma-translocation gene 1) is an intracellular signaling protein that activates NFκB and is crucial for both the adaptive and innate immune responses. Only 6 patients with immune deficiencies secondary to inherited mutations in the MALT1 gene have been described. Purpose: To provide clinical and immunological insights from 2 patients diagnosed with MALT1 immunodeficiency syndrome due to a novel MALT1 mutation. Methods: Two cousins with suspected combined immunodeficiency underwent immunological and genetic work-up, including lymphocyte phenotyping, lymphocyte activation by mitogen stimulation, and next-generation sequencing (NGS) of T cell receptor gamma chain (TRG) repertoire. Whole exome sequencing was performed to identify the underlying genetic defect. Results: Clinical findings included recurrent infections, failure to thrive, lymphadenopathy, dermatitis, and autoimmunity. Immune work-up revealed lymphocytosis, low to normal levels of immunoglobulins, absence of regulatory T cells, and low Th17 cells. A normal proliferative response was induced by phytohemagglutinin and IL-2 but was diminished with anti-CD3. TRG repertoire was diverse with a clonal expansion pattern. Genetic analysis identified a novel autosomal recessive homozygous c.1799T>A; p. I600N missense mutation in MALT1. MALT1 protein expression was markedly reduced, and in vitro IL-2 production and NFκB signaling pathway were significantly impaired. Conclusions: Two patients harboring a novel MALT1 mutation presented with signs of immune deficiency and dysregulation and were found to have an abnormal T cell receptor repertoire. These findings reinforce the link between MALT1 deficiency and combined immunodeficiency. Early diagnosis is crucial, and curative treatment by hematopoietic stem cell transplantation may be warranted. [ABSTRACT FROM AUTHOR]

Neutrophil chemotactic defects have been reported previously in patients with hyper-IgE syndrome. Bi-allelic mutations in dedicator of cytokinesis 8 (DOCK8) gene usually cause an autosomal recessive hyper-IgE syndrome phenotype. Data are lacking about expression of DOCK8 protein in neutrophils or the possible role of DOCK8 in neutrophil function. We sought to determine if DOCK8 protein is expressed in neutrophils and if DOCK8 plays a role in neutrophil function. The expression of DOCK8 protein was assessed in neutrophils from healthy volunteers with and without activators. Neutrophil chemotaxis, phagocytosis and superoxide generation were studied in neutrophils from DOCK8-deficient patients compared to neutrophils from healthy controls before and after stimulation with activators: phorbol 12-myristate 13-acetate (PMA) or N-Formylmethionyl-leucyl-phenylalanine (fMLP). DOCK8 protein is expressed in resting neutrophils from healthy controls, with a significant increase in DOCK8 expression after stimulation. Neutrophil functions were assessed in 6 DOCK8-deficient patients. All patients had the same non-sense mutation (c.C5134A, p.S1711X). Normal chemotaxis was recorded in 4/6 patients while a mild to moderate chemotaxis defect was recorded in 2/6. Superoxide generation was mainly normal in neutrophils from all six patients and phagocytosis was normal in five patients tested. We conclude that DOCK8 protein is expressed in resting human neutrophils and DOCK8 expression is increased after stimulation with either PMA or fMLP. Most patients with a disease-causing mutation in DOCK8 have normal neutrophil functions, while a minority showed a mild to moderate chemotactic defect. [ABSTRACT FROM AUTHOR]

Purpose: RAS guanyl-releasing protein 1 (RASGRP1) deficiency has recently been shown to cause a primary immunodeficiency (PID) characterized by CD4+ T cell lymphopenia and Epstein-Barr virus (EBV)-associated B cell lymphoma. Our report of three novel patients widens the scope of RASGRP1 deficiency by providing new clinical and immunological insights on autoimmunity, immune cell development, and predisposition to lymphoproliferative disease.Methods: One patient of Turkish origin (P1) and two Palestinian patients (P2, P3) were evaluated for immunodeficiency. To decipher the molecular cause of disease, whole exome sequencing was conducted. Identified mutations were validated by immunological and biochemical assays.Results: We report three patients presenting with similar clinical characteristics of immunodeficiency and EBV-associated lymphoproliferative disease. In addition, P2 and P3 exhibited overt autoimmune manifestations. Genetic screening identified two novel loss-of-function mutations in RASGRP1. Immunoblotting and active Ras pull-down assays confirmed perturbed ERK1/2 signaling and reduced Ras-GTPase activity in heterologous Jurkat cells with ectopic expression of RASGRP1 mutants. All three patients had CD4+ T cell lymphopenia. P2 and P3 showed decreased mitogen-induced lymphocyte proliferation, reduced T cell receptor excision circles, abnormal T cell receptor (TCR) Vβ repertoires, and increased frequencies of TCRγδ cells. TCR gamma repertoire diversity was significantly reduced with a remarkable clonal expansion.Conclusions: RASGRP1 deficiency is associated with life-threatening immune dysregulation, severe autoimmune manifestations, and susceptibility to EBV-induced B cell malignancies. Early diagnosis is critical and hematopoietic stem cell transplantation might be considered as curative treatment. [ABSTRACT FROM AUTHOR]

Newborn screening (NBS) programs for severe combined immunodeficiency (SCID), using the TREC-based assay, have enabled early diagnosis, prompt treatment, and eventually changed the natural history of affected infants. Nevertheless, it was believed that some affected infants with residual T cell, such as patients with MHC II deficiency, will be misdiagnosed by this assay. A full immune workup and genetic analysis using direct Sanger sequencing and whole exome sequencing have been performed to a patient that was identified by the Israeli NBS program for SCID. The patient was found to have severe CD4 lymphopenia with an inverted CD4/CD8 ratio, low TREC levels in peripheral blood, abnormal response to mitogen stimulation, and a skewed T cell receptor repertoire. HLA-DR expression on peripheral blood lymphocytes was undetectable suggesting a diagnosis of MHC II deficiency. Direct sequencing of the RFX5 gene revealed a stop codon change (p. R239X, c. C715T), which could cause the patient’s immune phenotype. His parents were found to be heterozygote carriers for the mutation. Whole exome sequencing could not identify other potential mutations to explain his immunodeficiency. The patient underwent successful conditioned hematopoietic stem cell transplantation from healthy matched unrelated donor and is currently well and alive with full chimerism. Infants with MHC class II deficiency can potentially be identified by the TREC-based assay NBS for SCID. Therefore, MHC II molecules (e.g., HLA-DR) measurement should be part of the confirmatory immune-phenotyping for patients with positive screening results. This will make the diagnosis of such patients straightforward. [ABSTRACT FROM AUTHOR]

Infants with severe combined immunodeficiency (SCID) are at risk of developing severe life-threatening infections if they are inadvertently given attenuated live vaccines. Concomitant appearance of two live vaccine-associated complications in one person is rarely reported. In this study, we present two SCID infants, who received BCG and oral polio vaccines according to their local immunization schedule early in life, before the diagnosis of immunodeficiency was made. Their clinical presentation, extensive immunological workup, genetic tests, and clinical disease course are presented. Both patients developed localized and disseminated infections originating from the BCG vaccine (BCGitis and BCGiosis, respectively) and in addition suffered from diarrhea and chronic fecal secretion of vaccine-derived poliovirus. Alarmingly, in case 2, the poliovirus was a type 2 vaccine-derived poliovirus in which both neurovirulence attenuation sites reverted to the neurovirulent genotype. These cases highlight the importance of early recognition of SCID by neonatal screening or thorough family anamnesis, and the need to further defer the timing of administration of attenuated live vaccines. [ABSTRACT FROM AUTHOR]

Background: Advances in genomics have facilitated the discovery of monogenic disorders in patients with unique gastro-intestinal phenotypes. Syndromic diarrhea, also called tricho-hepato-enteric (THE) syndrome, results from deleterious mutations in SKIV2L or TTC37 genes. The main features of this disorder are intractable diarrhea, abnormal hair, facial dysmorphism, immunodeficiency and liver disease.Aim: To report on a patient with THE syndrome and present the genetic analysis that facilitated diagnosis.Methods: Whole-exome sequencing (WES) was performed in a 4-month-old female with history of congenital diarrhea and severe failure to thrive but without hair anomalies or dysmorphism. Since the parents were first-degree cousins, the analysis focused on an autosomal recessive model. Sanger sequencing was used to validate suspected variants. Mutated protein structure was modeled to assess the effect of the mutation on protein function.Results: We identified an autosomal recessive C.1891G > A missense mutation (NM_006929) in SKIV2L gene that was previously described only in a compound heterozygous state as causing THE syndrome. The mutation was determined to be deleterious in multiple prediction models. Protein modeling suggested that the mutation has the potential to cause structural destabilization of SKIV2L, either through conformational changes, interference with the protein's packing, or changes at the protein's interface.Conclusions: THE syndrome can present with a broad range of clinical features in the neonatal period. WES is an important diagnostic tool in patients with congenital diarrhea and can facilitate diagnosis of various diseases presenting with atypical features. [ABSTRACT FROM AUTHOR]

Purpose: All reported patients with hypomorphic X-linked severe combined immunodeficiency (X-SCID) due to c.664C>T (p.R222C) mutations in the gene (IL2RG) encoding the common γ chain (γc) have presented with opportunistic infections within the first year of life, despite the presence of nearly normal NK and T cell numbers. Reporting five children of one extended family with hemizygous mutations in IL2RG, we explore potential diagnostic clues and extend our comprehension of the functional impact of this mutation.Methods: Whole exome sequencing (WES); detailed immune phenotyping; cytokine-induced STAT phosphorylation; B, T, and NK cell activation; and quantification of sjTRECs in five Arab children with c.664C>T (p.R222C) IL2RG mutation.Results: The mean age at clinical presentation with respiratory tract infection or diarrhea was 6.8 (range: 2-12) months. None of the children presented with opportunistic infections. Diagnostic clues were early onset in the first year of life, and a suggestive family history associated with reduced naïve CD4 T cells and absent switched memory B cells. Number and phenotype of NK cells and innate-like lymphocytes were normal. The diagnosis was made by WES and corroborated by absent STAT phosphorylation and reduced functional response after IL-2 and IL-21 stimulation. Four patients underwent successful hematopoietic stem cell transplantation.Conclusions: As early diagnosis and treatment are important, a high index of suspicion in the diagnosis of c.664C>T (p.R222C) X-SCID is needed. This requires prompt genetic testing by next generation sequencing in order to avoid unnecessary delays in the definite diagnosis since immunological work up may not be discriminating. Assays directly testing cytokine signaling or cytokine-dependent functions are helpful in confirming the functional impact of the identified hypomorphic variants. [ABSTRACT FROM AUTHOR]

Purpose: Chronic granulomatous disease (CGD) is an innate immune deficiency disorder of phagocytes, resulting from mutations in the components of the NADPH oxidase complex that impair the synthesis of oxygen radicals, thus rendering patients susceptible to recurrent infections and excessive hyperinflammatory responses. The most common autosomal recessive form of CGD is p47phox deficiency, which is often clinically milder than the more common X-linked recessive form. Here, we report data on genetics, clinical and biochemical findings in 17 CGD patients of Kavkazi origin with the nonsense mutation c.579G>A in the NCF1 gene, leading to p47phox deficiency.Methods: Diagnosis was based on detailed clinical evaluation, respiratory burst activity by cytochrome c reduction and dihydrorhodamine-1,2,3 (DHR) assay by flow cytometry, expression of p47phox by immunoblotting and molecular confirmation by DNA sequence analysis.Results: Twelve male and five female patients with median age at onset of 2.5 years (range 1 day to 9 years) were included in the study. The present cohort displays an encouraging 88% overall long-term survival, with median follow-up of 17 years. Clinical manifestations varied from mild to severe expression of the disease. Correlation between genotype and phenotype is unpredictable, although the Kavkazi patients were more severely affected than other patients with p47phox deficiency.Conclusions: Kavkazi CGD patients harbor a common genetic mutation that is associated with a heterogeneous clinical phenotype. Early diagnosis and proper clinical management in an experienced phagocytic leukocyte center is imperative to ensure favorable patient outcome. New treatment strategies are ongoing, but results are not yet conclusive. [ABSTRACT FROM AUTHOR]

Severe combined immunodeficiency (SCID), the most severe form of T cell immunodeficiency, is detectable through quantification of T cell receptor excision circles (TRECs) in dried blood spots obtained at birth. Herein, we describe the results of the first year of the Israeli SCID newborn screening (NBS) program. This important, life-saving screening test is available at no cost for every newborn in Israel. Eight SCID patients were diagnosed through the NBS program in its first year, revealing an incidence of 1:22,500 births in the Israeli population. Consanguine marriages and Muslim ethnic origin were found to be a risk factor in affected newborns, and a founder effect was detected for both IL7Rα and DCLRE1C deficiency SCID. Lymphocyte subset analysis and TREC quantification in the peripheral blood appear to be sufficient for confirmation of typical and leaky SCID and ruling out false positive (FP) results. Detection of secondary targets (infants with non-SCID lymphopenia) did not significantly affect the management or outcomes of these infants in our cohort. In the general, non-immunodeficient population, TREC rises along with gestational age and birth weight, and is significantly higher in females and the firstborn of twin pairs. Low TREC correlates with both gestational age and birth weight in extremely premature newborns. Additionally, the rate of TREC increase per week consistently accelerates with gestational age. Together, these findings mandate a lower cutoff or a more lenient screening algorithm for extremely premature infants, in order to reduce the high rate of FPs within this group. A significant surge in TREC values was observed between 28 and 30 weeks of gestation, where median TREC copy numbers rise by 50% over 2 weeks. These findings suggest a maturational step in T cell development around week 29 gestation, and imply moderate to late preterms should be screened with the same cutoff as term infants. The SCID NBS program is still in its infancy, but is already bearing fruit in the early detection and improved outcomes of children with SCID in Israel and other countries. [ABSTRACT FROM AUTHOR]

A mature and diverse T and B cell receptor repertoire is a prerequisite for immunocompetence. In light of its increased susceptibility to infection, the human fetus has long been considered deficient in this regard. However, data accumulated since the 1990s and in earnest in the past couple of years paints a more complicated picture. As we describe in this review, mechanisms responsible for generating a diverse receptor repertoire, such as somatic recombination, class switch recombination, and somatic hypermutation, are all operational to surprising extents in the growing fetus. The composition of the fetal repertoire differs from that of adults, with preferential usage of certain variable (V), diversity (D), and joining (J) gene segments and a shorter complementarity determining (CDR3) region, primarily due to decreased terminal deoxynucleotidyl transferase (TdT) expression. Both T and B cell receptor repertoires are extremely diverse by the end of the second trimester, and in the case of T cells, are capable of responding to an invading pathogen with in utero clonal expansion. Thus, it would appear as though the T and B cell receptor repertoires are not a hindrance towards immunocompetence of the newborn. Our improved understanding of fetal receptor repertoire development is already bearing fruit in the early diagnosis of primary immunodeficiencies (PID) and may help clarify the pathogenesis of congenital infections, recurrent abortions, and autoimmune disorders in the near future. [ABSTRACT FROM AUTHOR]

Immunodeficiency-associated vaccine-derived polioviruses (iVDPVs) have been isolated from primary immunodeficiency (PID) patients exposed to oral poliovirus vaccine (OPV). Patients may excrete poliovirus strains for months or years; the excreted viruses are frequently highly divergent from the parental OPV and have been shown to be as neurovirulent as wild virus. Thus, these patients represent a potential reservoir for transmission of neurovirulent polioviruses in the post-eradication era. In support of WHO recommendations to better estimate the prevalence of poliovirus excreters among PIDs and characterize genetic evolution of these strains, 635 patients including 570 with primary antibody deficiencies and 65 combined immunodeficiencies were studied from 13 OPV-using countries. Two stool samples were collected over 4 days, tested for enterovirus, and the poliovirus positive samples were sequenced. Thirteen patients (2%) excreted polioviruses, most for less than 2 months following identification of infection. Five (0.8%) were classified as iVDPVs (only in combined immunodeficiencies and mostly poliovirus serotype 2). Non-polio enteroviruses were detected in 30 patients (4.7%). Patients with combined immunodeficiencies had increased risk of delayed poliovirus clearance compared to primary antibody deficiencies. Usually, iVDPV was detected in subjects with combined immunodeficiencies in a short period of time after OPV exposure, most for less than 6 months. Surveillance for poliovirus excretion among PID patients should be reinforced until polio eradication is certified and the use of OPV is stopped. Survival rates among PID patients are improving in lower and middle income countries, and iVDPV excreters are identified more frequently. Antivirals or enhanced immunotherapies presently in development represent the only potential means to manage the treatment of prolonged excreters and the risk they present to the polio endgame. [ABSTRACT FROM AUTHOR]

Mutations in the dedicator of cytokinesis 8 (DOCK8) gene cause a combined immunodeficiency usually diagnosed as autosomal recessive hyper IgE syndrome. We sought to reveal the varying manifestations in patients with a unique mutation in DOCK8 gene by a retrospective medical record review. Ten patients from five consanguineous families and three tribes were included. Seven patients were homozygous for the c.C5134A, p.S1711X mutation, and the remaining three patients were their siblings manifesting hyper IgE syndrome features without a genetic diagnosis. Prior to the genetic diagnosis, the clinical diagnosis was 'hyper IgE syndrome' in six patients and 'anti-pneumococcal antibody deficiency,' 'recurrent pneumonia with bronchiectasis,' and 'asthma with hypereosinophilic syndrome' each diagnosed once. One additional patient was diagnosed due to family history. The age of presentation varied from 1 to 16 months. Eczema was diagnosed in all patients, food allergies in three, and severe herpes keratitis or malignancy or autoimmunity in two patients. Elevated IgE was recorded in nine patients; however, in six patients, the initial serum IgE concentration was equal to or less than three times the normal concentration for age, and in these patients, the median age at IgE evaluation was 7.5 months compared with 21.5 months in patients with an initial IgE concentration above three times the normal concentration for age ( P = 0.067). The spectrum of disease manifestations in patients with a unique mutation in DOCK8 is variable. The genotype-phenotype correlations may be modified by genetic and/or epigenetic modifiers beyond the monogenic effect. Younger patients tend to have lower IgE concentrations at the initial measurement of IgE. [ABSTRACT FROM AUTHOR]

22q11.2 deletion syndrome (22q11.2DS) has a wide range of clinical features including endocrine abnormalities. We aimed to characterize growth patterns, hypoparathyroidism, and thyroid dysfunction of individuals with 22q11.2DS. Anthropometric and laboratory measurements were obtained from the charts of 48 individuals (males=28, 8.0±6.8 visits/participant) followed at a national 22q11.2DS clinic between 2009 and 2016. Age at diagnosis was 4.3±4.9 years and age at last evaluation 11.2±7.2 years. Median height-SDS was negative at all ages. Height-SDS at last visit was correlated to the midparental height-SDS ( r=0.52 P=0.002). Yet, participants did not reach their target height, with a difference of 1.06±1.07 SD ( P <0.0001). Height-SDS at last visit of participants with a heart defect was lower compared to participants with a normal heart (−1.5±1.4 vs. −0.6±0.8, P=0.036), with lower height-SDS in the subgroup of participants with severe heart defects (−2.1±1.6, P=0.009). Mean IGF1-SDS was low (−0.99±1.68) but was not correlated with height-SDS. Thirteen patients (27%) had hypoparathyroidism: 10 presented during infancy and 3 during adolescence. Five patients (10.4%, female=4) had thyroid abnormalities. In conclusions, individuals with 22q11.2 DS have a distinct growth pattern consisting of growth restriction at all ages, resulting in final adult height in the low-normal range. Hypoparathyroidism is common and may present during the neonatal period as well as later in life. Thyroid abnormalities may present during childhood, adolescence, or adulthood. [ABSTRACT FROM AUTHOR]