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Inborn errors of immunity include multiple genetic abnormalities affecting different components of the innate and adaptive immune systems. More than 450 genes have been described so far including DNA repair defects which may result in predisposition to infections, but also malignancies, neurologic abnormalities and growth retardation. The group of patients with DNA repair and methylation defects exhibit impaired adaptive immunity, which increases susceptibility to infections due to impaired repertoire diversity. In this context, we aimed to investigate the TCRvβ repertoire and its interaction with clinical entities in a group of IEI patients with DNA repair defects including ATM, DCLRE1C, DNA-PRKDC, DNA ligase-4, and BLM. Thirty-nine patients with evidence of DNA repair defects and radiosensitivity and 15 age-matched healthy controls were included in this study. Peripheral lymphocyte subset and TCR-vβ repertoire analyses were performed by flow cytometry. To contrast TCR-repertoire in patients with DNA repair defects to healthy controls, we extracted data on lymphocyte phenotype, thymic function, immunoglobulins, and analysis of the TCRvβ repertoire from a prior study. The entire TCR-vβ repertoire was detected in all patients. However, compared with the control group, 9 of 24 clones (37.5%) were statistically significantly lower, whereas only 3 clones had high levels (p

Purpose: MALT1 deficiency is a combined immune deficiency characterized by recurrent infections, eczema, chronic diarrhea, and failure to thrive. Clinical and immunological characterizations of the disease have not been previously reported in large cohorts. We sought to determine the clinical, immunological, genetic features, and the natural history of MALT-1 deficiency. Methods: The clinical findings and treatment outcomes were evaluated in nine new MALT1-deficient patients. Peripheral lymphocyte subset analyses, cytokine secretion, and proliferation assays were performed. We also analyzed ten previously reported patients to comprehensively evaluate genotype/phenotype correlation. Results: The mean age of patients and disease onset were 33 ± 17 and 1.6 ± 0.7months, respectively. The main clinical findings of the disease were recurrent infections (100%), skin involvement (100%), failure to thrive (100%), oral lesions (67%), chronic diarrhea (56%), and autoimmunity (44%). Eosinophilia and high IgE were observed in six (67%) and two (22%) patients, respectively. The majority of patients had normal T and NK cells, while eight (89%) exhibited reduced B cells. Immunoglobulin replacement and antibiotics prophylaxis were mostly ineffective in reducing the frequency of infections and other complications. One patient received hematopoietic stem cell transplantation (HSCT) and five patients died as a complication of life-threatening infections. Analyzing this cohort with reported patients revealed overall survival in 58% (11/19), which was higher in patients who underwent HSCT (P = 0.03). Conclusion: This cohort provides the largest analysis for clinical and immunological features of MALT1 deficiency. HSCT should be offered as a curative therapeutic option for all patients at the early stage of life.

BACKGROUND: Inborn errors of immunity (IEI) are rare diseases, which makes diagnosis a challenge. A better description of the initial presenting manifestations should improve awareness and avoid diagnostic delay. Although increased infection susceptibility is a well-known initial IEI manifestation, less is known about the frequency of other presenting manifestations.OBJECTIVE: We sought to analyze age-related initial presenting manifestations of IEI including different IEI disease cohorts.METHODS: We analyzed data on 16,486 patients of the European Society for Immunodeficiencies Registry. Patients with autoinflammatory diseases were excluded because of the limited number registered.RESULTS: Overall, 68% of patients initially presented with infections only, 9% with immune dysregulation only, and 9% with a combination of both. Syndromic features were the presenting feature in 12%, 4% had laboratory abnormalities only, 1.5% were diagnosed because of family history only, and 0.8% presented with malignancy. Two-third of patients with IEI presented before the age of 6 years, but a quarter of patients developed initial symptoms only as adults. Immune dysregulation was most frequently recognized as an initial IEI manifestation between age 6 and 25 years, with male predominance until age 10 years, shifting to female predominance after age 40 years. Infections were most prevalent as a first manifestation in patients presenting after age 30 years.CONCLUSIONS: An exclusive focus on infection-centered warning signs would have missed around 25% of patients with IEI who initially present with other manifestations.

Background: A novel type of Coronavirus emerged at Wuhan in late 2019 involving preferentially the respiratory system. Owing to the rapid spread, almost 22 million people became infected and 700,000 died. Similar to other countries, the need for additional hospital beds and intensive care units required diversion of health care resources toward the care for those with COVID-19 in Turkey. Telemedicine appeared as a safe and low-cost alternative for the maintainability of pediatric health services during the pandemics. Within this context, we aimed to deliver the health services through telemedicine during the follow-up of chronic childhood diseases. Materials and Methods: This prospective study included five pediatric subspecialties, including allergy immunology, hematology and oncology, nephrology, rheumatology, and inborn metabolic disorders. After the interview, patients and involved physicians were requested to fill out a questionnaire designed to measure the level of satisfaction and the quality of the service we offered. Results: Of the 263 interviews, overall patient and physician satisfaction was 99% and 87%, respectively. As results of the interviews, 250 routine visits were performed, 181 acute complaints were assessed, drug changes were made in 118 patients, 9 patients were determined to be unable to get their drugs, and 12 who misused their drugs. The main advantage of the telemedicine declared by the patients was "not to waste time for transportation." The main concerns of the participants were inability to perform physical and laboratory examinations. Conclusion: Consequently, we considered telemedicine as a feasible alternative not only during pandemics but also in daily practice in Turkey.

Background: Several factors that increase the risk of severe food-induced anaphylaxis have been identified. Objective: We aimed to determine the demographic, etiologic, and clinical features of food-induced anaphylaxis in early childhood and also any other factors associated with severe anaphylaxis. Methods: We carried out a medical chart review of anaphylaxis cases from 16 pediatric allergy and immunology centers in Turkey. Results: The data of 227 patients with 266 food-induced anaphylaxis episodes were included in the study. The median (interquartile range) age of the first anaphylaxis episode was 9 months (6‐18 months); 160 of these patients were boys (70.5%). The anaphylaxis episodes were mild in 75 cases (28.2%), moderate in 154 cases (57.9%), and severe in 37 cases (13.9%). The most frequent food allergens involved were cow's milk (47.4%), nuts (16.7%), and hen's egg (15.8%). Epinephrine was administered in only 98 (36.8%) of these anaphylaxis episodes. A logistic regression analysis revealed two statistically significant factors that were independently associated with severe anaphylaxis: the presence of angioedema and hoarseness during the anaphylactic episode. Urticaria was observed less frequently in patients who developed hypotension. In addition, confusion and syncope were associated with 25.9- and 44.6-fold increases, respectively, in the risk of concomitant hypotension. Conclusion: Cow's milk, nuts, and hen's egg caused the majority of mild and moderate-to-severe anaphylaxis episodes. The presence of angioedema and hoarseness in any patient who presents with a history of food-induced anaphylaxis should alert clinicians that the reaction may be severe. In addition, the presence of confusion, syncope, or stridor probably indicates concomitant hypotension.

Multisystem inflammatory syndrome in children (MIS-C) evolves in some pediatric patients following acute infection with SARS-CoV-2 by hitherto unknown mechanisms. Whereas acute-COVID-19 severity and outcomes were previously correlated with Notch4 expression on Tregs, here, we show that Tregs in MIS-C were destabilized through a Notch1-dependent mechanism. Genetic analysis revealed that patients with MIS-C had enrichment of rare deleterious variants affecting inflammation and autoimmunity pathways, including dominant-negative mutations in the Notch1 regulators NUMB and NUMBL leading to Notch1 upregulation. Notch1 signaling in Tregs induced CD22, leading to their destabilization in a mTORC1-dependent manner and to the promotion of systemic inflammation. These results identify a Notch1/CD22 signaling axis that disrupts Treg function in MIS-C and point to distinct immune checkpoints controlled by individual Treg Notch receptors that shape the inflammatory outcome in SARS-CoV-2 infection.

© 2022 EAACI and John Wiley and Sons A/S. Published by John Wiley and Sons Ltd.Background: Lipopolysaccharide-responsive beige-like anchor protein (LRBA) deficiency and cytotoxic T-lymphocyte protein-4 (CTLA-4) insufficiency are recently described disorders that present with susceptibility to infections, autoimmunity, and lymphoproliferation. Clinical and immunological comparisons of the diseases with long-term follow-up have not been previously reported. We sought to compare the clinical and laboratory manifestations of both diseases and investigate the role of flow cytometry in predicting the genetic defect in patients with LRBA deficiency and CTLA-4 insufficiency. Methods: Patients were evaluated clinically with laboratory assessments for lymphocyte subsets, T follicular helper cells (TFH), LRBA expression, and expression of CD25, FOXP3, and CTLA4 in regulatory T cells (Tregs) at baseline and 16 h post-stimulation. Results: LRBA-deficient patients (n = 29) showed significantly early age of symptom onset, higher rates of pneumonia, autoimmunity, chronic diarrhea, and failure to thrive compared to CTLA-4 insufficiency (n = 12). In total, 29 patients received abatacept with favorable responses and the overall survival probability was not different between transplanted versus non-transplanted patients in LRBA deficiency. Meanwhile, higher probability of survival was observed in CTLA-4-insufficient patients (p = 0.04). The T-cell subsets showed more deviation to memory cells in CTLA-4-insufficiency, accompanied by low percentages of Treg and dysregulated cTFH cells response in both diseases. Cumulative numbers of autoimmunities positively correlated with cTFH frequencies. Baseline CTLA-4 expression was significantly diminished in LRBA deficiency and CTLA-4 insufficiency, but significant induction in CTLA-4 was observed after short-term T-cell stimulation in LRBA deficiency and controls, while this elevation was less in CTLA-4 insufficiency, allowing to differentiate this disease from LRBA deficiency with high sensitivity (87.5%) and specificity (90%). Conclusion: This cohort provided detailed clinical and laboratory comparisons for LRBA deficiency and CTLA-4 insufficiency. The flow cytometric approach is useful in predicting the defective gene; thus, targeted sequencing can be conducted to provide rapid diagnosis and treatment for these diseases impacting the CTLA-4 pathway.

The molecular programs involved in regulatory T (T reg ) cell activation and homeostasis remain incompletely understood. Here, we show that T cell receptor (TCR) signaling in T reg cells induces the nuclear translocation of serine/threonine kinase 4 (Stk4), leading to the formation of an Stk4–NF-κB p65–Foxp3 complex that regulates Foxp3- and p65-dependent transcriptional programs. This complex was stabilized by Stk4-dependent phosphorylation of Foxp3 on serine-418. Stk4 deficiency in T reg cells, either alone or in combination with its homolog Stk3, precipitated a fatal autoimmune lymphoproliferative disease in mice characterized by decreased T reg cell p65 expression and nuclear translocation, impaired NF-κB p65–Foxp3 complex formation, and defective T reg cell activation. In an adoptive immunotherapy model, overexpression of p65 or the phosphomimetic Foxp3 S418E in Stk3/4-deficient T reg cells ameliorated their immune regulatory defects. Our studies identify Stk4 as an essential TCR-responsive regulator of p65-Foxp3–dependent transcription that promotes T reg cell–mediated immune tolerance.

The molecular programs involved in regulatory T (Treg) cell activation and homeostasis remain incompletely understood. Here we show that T cell receptor (TCR) signaling in Treg cells induces the nuclear translocation of serine/threonine kinase 4 (Stk4), leading to the formation of a Stk4/NF-κB p65/Foxp3 complex that regulates Foxp3 and p65-dependent transcriptional programs. This complex was stabilized by Stk4-dependent phosphorylation of Foxp3 serine 418. Stk4 deficiency in Treg cells, either alone or in combination with its homologue Stk3, precipitated a fatal autoimmune lymphoproliferative disease in mice characterized by decreased Treg cell p65 expression and nuclear translocation, impaired NF-κB p65/Foxp3 complex formation, and defective Treg cell activation. In an adoptive immunotherapy model, over-expression of p65 or the phosphomimetic Foxp3(S418E) in Stk3/4-deficient Treg cells ameliorated their immune regulatory defects. Our studies identify Stk4 as an essential TCR-responsive regulator of p65-Foxp3-dependent transcription that promotes Treg cell-mediated immune tolerance.

Background/aim Established reference values are critical for the interpretation of immunologic assessments. In particular, the proportion and absolute counts of T- and B- cell subpopulations are subject to change with age and ethnicity. We aimed to establish age- specific reference values for lymphocyte subsets using updated immunophenotyping panels. Materials and methods We studied a total of 297 healthy Turkish subjects aged 0 to 50 years, stratified into major age brackets in a cluster factor of 10 per age-group. The predetermined age intervals contained randomly allocated participants enrolled over a period of 6 months, who were homogenously distributed by sex. We analyzed a complete blood count test and simultaneously with detailed immunophenotyping enumerated the percent and absolute cell counts of lymphocyte subsets. Results The percentage and absolute counts of lymphocyte subsets show a marked surge across the age-span. T helper, T cytotoxic, and the natural killer cell numbers were increasing from birth until 6 months, followed by a gradual decrease thereafter. B cell numbers were rising until 2 years, followed by a gradual decrease for the upcoming years, accompanied by a steady expansion of unclass-switched- and class-switched- B cells. Conclusion We provide updated extensive reference intervals for lymphocyte subpopulations in Turkish people.

Background: Compared with the general population, the immune response to COVID-19 mRNA vaccines is lower in adult kidney transplant recipients (KTRs). However, data is limited for pediatric KTRs. In this study, we aimed to assess humoral and cellular immune responses to the COVID-19 mRNA vaccine in pediatric KTRs. Methods: This multicenter, prospective, case-control study included 63 KTRs (37 male, aged 12-21 years), 19 dialysis patients, and 19 controls. Humoral (anti-SARS-CoV2 IgG, neutralizing Ab (nAb)) and cellular (interferon-gamma release assay (IGRA)) immune responses were assessed at least one month after two doses of BNT162b2 mRNA vaccine. Results: Among COVID-19 naïve KTRs (n = 46), 76.1% tested positive for anti-SARS-CoV-2 IgG, 54.3% for nAb, and 63% for IGRA. Serum levels of anti-SARS-CoV-2 IgG and nAb activity were significantly lower in KTRs compared to dialysis and control groups (p < 0.05 for all). Seropositivity in KTRs was independently associated with shorter transplant duration (p = 0.005), and higher eGFR (p = 0.007). IGRA titer was significantly lower than dialysis patients (p = 0.009). Twenty (43.4%) KTRs were positive for all immune parameters. Only four of 11 seronegative KTRs were IGRA-positive. COVID-19 recovered KTRs had significantly higher anti-SARS-CoV-2 IgG and nAb activity levels than COVID-19 naïve KTRs (p = 0.018 and p = 0.007, respectively). Conclusions: The humoral and cellular immune responses to SARS-CoV-2 mRNA BNT162b2 vaccine are lower in pediatric KTRs compared to dialysis patients. Further prospective studies are required to demonstrate the clinical efficacy of the mRNA vaccine in KTRs. This prospective study was registered in ClinicalTrials.gov (NCT05465863, registered retrospectively at 20.07.2022). A higher resolution version of the Graphical abstract is available as Supplementary information. 36459243

To the Editor: FCH And Mu Domain Containing Endocytic Adaptor 1 (FCHO1) gene encodes a protein that plays a critical role in clathrin-mediated endocytosis, a biological process that maintains cellular functions in signaling, nutrient- and growth factor- uptake, and diferentiation [1–3]. Recently, biallelic mutations in FCHO1 were linked to a combined immunodefciency that is characterized by recurrent infections caused by bacteria, viruses, mycobacteria, fungi, T cell lymphopenia, and hypogammaglobulinemia [4, 5]. Sidra Precision Medicine Program

Introduction: Primary immunodeficiencies are a heterogeneous group of diseases associated with an increased incidence of infections, autoimmunity, autoinflammatory diseases, allergies, and cancer. Rhinosinusitis is one of the most common infections in these patients. In our study, we aimed to determine the presence of chronic rhinosinusitis in our patients with primary immunodeficiency and to investigate the etiology of chronic rhinosinusitis. Methods: Forty-four patients (age range: 4–26 years) diagnosed with primary immunodeficiency were enrolled in our study. Patients were interviewed about the symptoms of chronic rhinosinusitis, and nasal endoscopic examinations were performed prospectively. The results of laboratory tests, medications, skin allergy tests, and the patients’ lung computed tomography were retrospectively recorded from patient files. Results: The distribution of patients’ diagnoses included 38.6% (n = 17) primary antibody deficiencies, 6.6% (n = 3) combined immunodeficiencies, 27.3% (n = 12) combined immunodeficiencies with syndromic features, 6.8% (n = 3) phagocytic disorders, and 20.5% (n = 9) immune dysregulation disorders. There was no significant difference in the frequency of chronic rhinosinusitis among the different immunodeficiency groups. There were no significant differences between chronic rhinosinusitis and conditions such as atopy, hypogammaglobulinemia, and treatments with immunoglobulin and/or azithromycin. The incidence of chronic rhinosinusitis was 77.8% (n = 7) in patients with a history of acute sinusitis and 20% (n = 7) in patients without a history of sinusitis, with a statistically significant difference between them (p = 0.002). Conclusion: Chronic rhinosinusitis is more common in patients with primary immunodeficiencies than in the normal population. For effective treatment, it is necessary to identify the factors that cause chronic rhinosinusitis. Further studies involving larger patient populations are needed to explain the mechanisms of chronic rhinosinusitis.

Multisystem inflammatory syndrome in children (MIS-C) evolves in some pediatric patients following acute infection with SARS-CoV-2 by hitherto unknown mechanisms. Whereas acute-COVID-19 severity and outcome were previously correlated with Notch4 expression on regulatory T (Treg) cells, here we show that the Treg cells in MIS-C are destabilized in association with increased Notch1 expression. Genetic analysis revealed that MIS-C patients were enriched in rare deleterious variant impacting inflammation and autoimmunity pathways, including dominant negative mutations in the Notch1 regulators NUMB and NUMBL. Notch1 signaling in Treg cells induced CD22, leading to their destabilization in an mTORC1 dependent manner and to the promotion of systemic inflammation. These results establish a Notch1-CD22 signaling axis that disrupts Treg cell function in MIS-C and point to distinct immune checkpoints controlled by individual Treg cell Notch receptors that shape the inflammatory outcome in SARS-CoV-2 infection.

Human Inborn Errors of Immunity (IEIs) are clinically and genetically heterogeneous group of diseases, with relatively mild clinical course or severe types that can be life-threatening. Severe combined immunodeficiency (SCID) is the most severe form of IEIs, which is caused by monogenic defects that impair the proliferation and function of T, B, and NK cells. According to the most recent report by the International Union of Immunological Societies (IUIS), SCID is caused by mutations in IL2RG, JAK3, FOXN1, CORO1A, PTPRC, CD3D, CD3E, CD247, ADA, AK2, NHEJ1, LIG4, PRKDC, DCLRE1C, RAG1 and RAG2 genes. The targeted next-generation sequencing (TNGS) workflow based on Ion AmpliSeq (TM) Primary Immune Deficiency Research Panel was designed for sequencing 264 IEI-related genes on Ion S5 (TM) Sequencer. Herein, we present 21 disease-causing variants (12 novel) which were identified in 22 patients in eight different SCID genes. Next-generation sequencing allowed a rapid and an accurate diagnosis SCID patients.

© 2021 European Academy of Allergy and Clinical Immunology and John Wiley & Sons Ltd. This article has been contributed to by US Government employees and their work is in the public domain in the USA.Background: Biallelic loss-of-function mutations in CARMIL2 cause combined immunodeficiency associated with dermatitis, inflammatory bowel disease (IBD), and EBV-related smooth muscle tumors. Clinical and immunological characterizations of the disease with long-term follow-up and treatment options have not been previously reported in large cohorts. We sought to determine the clinical and immunological features of CARMIL2 deficiency and long-term efficacy of treatment in controlling different disease manifestations. Methods: The presenting phenotypes, long-term outcomes, and treatment responses were evaluated prospectively in 15 CARMIL2-deficient patients, including 13 novel cases. Lymphocyte subpopulations, protein expression, regulatory T (Treg), and circulating T follicular helper (cTFH) cells were analyzed. Three-dimensional (3D) migration assay was performed to determine T-cell shape. Results: Mean age at disease onset was 38 ± 23 months. Main clinical features were skin manifestations (n = 14, 93%), failure to thrive (n = 10, 67%), recurrent infections (n = 10, 67%), allergic symptoms (n = 8, 53%), chronic diarrhea (n = 4, 27%), and EBV-related leiomyoma (n = 2, 13%). Skin manifestations ranged from atopic and seborrheic dermatitis to psoriasiform rash. Patients had reduced proportions of memory CD4+ T cells, Treg, and cTFH cells. Memory B and NK cells were also decreased. CARMIL2-deficient T cells exhibited reduced T-cell proliferation and cytokine production following CD28 co-stimulation and normal morphology when migrating in a high-density 3D collagen gel matrix. IBD was the most severe clinical manifestation, leading to growth retardation, requiring multiple interventional treatments. All patients were alive with a median follow-up of 10.8 years (range: 3–17 years). Conclusion: This cohort provides clinical and immunological features and long-term follow-up of different manifestations of CARMIL2 deficiency.

The biological role of the lipopolysaccharide-responsive beige-like anchor (LRBA) protein associated with the immune system is not to date well known. However, it is thought to regulate the CTLA4 protein, an inhibitory immunoreceptor. Chronic diarrhea, autoimmune disorders, organomegaly, frequent recurrent infections, hypogammaglobulinemia, chronic lung manifestations, and growth retardation are some features of LRBA deficiency. This rare disease is observed as a result of homozygous mutations in the LRBA gene. An 11.3-year-old male patient presented because of short stature and high blood glucose level. He had a previous history of lymphoproliferative disease, chronic diarrhea, and recurrent infections. His parents were first-degree consanguineous relatives. A diagnosis of type 1 diabetes mellitus (T1DM) was added to the preexisting diagnoses of immunodeficiency, recurrent infection, enteropathy, chronic diarrhea, lymphadenopathy, hepatomegaly, and short stature. Genetic analysis revealed a homozygous mutation in the LRBA gene, c.5047C>T (p.R1683*) (p.Arg1683*). Abatacept treatment was started: the patient's hospital admission frequency decreased, and glucose regulation improved. At follow-up, growth hormone (GH) deficiency was diagnosed, although it was not treated because the underlying disease was not under control. Nevertheless, the patient's height improved with abatacept treatment. LRBA deficiency should be considered in the presence of consanguineous marriage, diabetes, immunodeficiency, and additional autoimmune symptoms. LRBA phenotypes are variable even when the same variants in the LRBA gene are present. Genetic diagnosis is important to determine optimal treatment options. In addition to chronic malnutrition and immunosuppressive therapy, GH deficiency may be one of the causes of short stature in these patients.

Severe combined immunodeficiency (SCID) has a diverse genetic aetiology, where a clinical phenotype, caused by single and/or multiple gene variants, can give rise to multiple presentations. The advent of next-generation sequencing (NGS) has recently enabled rapid identification of the molecular aetiology of SCID, which is crucial for prognosis and treatment strategies. We sought to identify the genetic aetiology of various phenotypes of SCIDs and assessed both clinical and immunologic characteristics associated with gene variants. An amplicon-based targeted NGS panel, which contained 18 most common SCID-related genes, was contumely made to screen the patients (n = 38) with typical SCID, atypical SCID or OMENN syndrome. Allelic segregations were confirmed for the detected gene variants within the families. In total, 24 disease-causing variants (17 known and 7 novel) were identified in 23 patients in 9 different SCID genes: RAG1 (n = 5), RAG2 (n = 2), ADA (n = 3), DCLRE1C (n = 2), NHEJ1 (n = 2), CD3E (n = 2), IL2RG (n = 3), JAK3 (n = 4) and IL7R (n = 1). The overall success rate of our custom-made NGS panel was 60% (39.3% for NK+ SCID and 100% for NK- SCID). Incidence of autosomal-recessive inherited genes is more frequently found in our cohort than the previously reported populations probably due to the high consanguineous marriages in Turkey. In conclusion, the custom-made sequencing panel was able to identify and confirm the previously known and novel disease-causing variants with high accuracy. Istanbul Bilgi UniversityIstanbul Bilgi University [NGYY-2018.01.0006]; Bilimsel Arastirma Projeleri Birimi, Istanbul Universitesi [52575, 20499] Istanbul Bilgi University, Grant/Award Number: NGYY-2018.01.0006; Bilimsel Arastirma Projeleri Birimi, Istanbul Universitesi, Grant/Award Number: 52575 and 20499 WOS:000534741000001 32445296 Q4

Background: Besides local reactions, systemic hypersensitivity reactions such as urticaria, anaphylaxis, serum sickness and Henoch-Schönlein purpura (HSP) have been reported during gonadotropin-releasing hormone (GnRH) analogue treatment. Aim: To present the clinical presentation of 9 cases with systemic hypersensitivity reactions to GnRH analogues and discuss the management of such reactions based on our experience. Patients and Methods: Nine of 232 (3.8%) patients with central precocious puberty receiving GnRH analogue treatment had systemic hypersensitivity reactions in 4 years’ period. Six patients had a type 1 hypersensitivity reaction (generalized hives, pruritus, and/or edema) to triptorelin acetate (TA), 2 patients to leuprolide acetate (LA), and 1 patient to both medications who also developed anaphylaxis to LA during intradermal test (IDT). Another patient on TA had skin lesions suggestive of HSP. GnRH analogue treatment was discontinued in 2 patients after discussion with the parents. Treatment was changed to another GnRH analogue preparation in 6 patients and was maintained with the same medication with antihistamines and corticosteroid premedication in 1 patient. None of the patients developed new reactions after these precautions. Conclusion: Systemic hypersensitivity reactions should be carefully evaluated and cross-reaction to the other GnRH analogues should be kept in mind. Discontinuation of GnRH analogue is always an option. However, if continuation of GnRH analogue is elected, we recommend switching to an alternative GnRH analogue, which should be considered only after a skin prick test (SPT) and IDT. In the lack of the possibility to perform SPT and IDT, injections may be administered under strict medical supervision in a well-equipped facility to manage anaphylaxis. We discuss additional options in situations where alternative GnRH analogues are unavailable, which enabled us to continue treatment in most cases without further problems.

Introduction: Common variable immunodeficiency (CVID) is characterized by recurrent infections, autoimmunity, lymphoproliferation, hypogammaglobulinemia, and defective antibody production. In CVID, B-cell abnormalities were described to predict end organ involvement and prognosis. Pediatric-onset CVID is much rarer than adult CVID, and lymphocyte subset abnormalities have not been thoroughly evaluated. Objective: We sought to determine lymphocyte subset abnormalities and their association with end organ involvement in pediatric-onset CVID patients. Methods: The clinical manifestations and laboratory findings including absolute numbers and percentages of B-, T-, and NK cell populations were assessed in pediatric-onset CVID patients and compared to age-matched healthy controls. The patients were divided into 2 groups according to age at assessment (pediatric CVID patients: 10–16 years, n = 9; and adult CVID patients: >16 years, n = 13). The comparisons between lymphocyte subsets and organ involvement were also evaluated. Results: Mean age at symptom onset was 18 (3–204) months. All CVID patients with pediatric onset had decreased levels of total and memory B cells, CD4+ T cells, CD4+CD45RA+ naive T cells, and recent thymic emigrant (RTE) cells. On the other hand, they had increases in CD8+CD45RO+ memory T cells. Interestingly, adult CVID patients demonstrated high frequencies of activated and double-negative T cells, which were unique only for this group of patients. Specific cellular abnormalities associated with the reduction in B and NK cells and increase in CD8+ T cells were found in patients with bronchiectasis. Moreover, in pediatric CVID patients, low serum IgA levels and decreased numbers of naive T and RTE cells were determined as risk factors for chronic diarrhea. Conclusions: Specific abnormalities in B- and T-lymphocyte compartments were identified in pediatric-onset CVID patients and appear to be associated with end organ manifestations.

Primary antibody deficiencies (PAD) are the most common subtype of primary immunodeficiencies, characterized by increased susceptibility to infections and autoimmunity, allergy, or malignancy predisposition. PAD syndromes comprise of immune system genes highlighted the key role of B cell activation, proliferation, migration, somatic hypermutation, or isotype switching have a wide spectrum from agammaglobulinemia to selective Ig deficiency. In this study, we describe the molecular and the clinical aspects of fifty-two PAD patients. The most common symptoms of our cohort were upper and lower respiratory infections, bronchiectasis, diarrhea, and recurrent fever. Almost all patients (98%) had at least one of the symptoms like autoimmunity, lymphoproliferation, allergy, or gastrointestinal disease. A custom-made next-generation sequencing (NGS) panel, which contains 24 genes, was designed to identify well-known disease-causing variants in our cohort. We identified eight variants (15.4%) among 52 PAD patients. The variants mapped to BTK (n = 4), CD40L (n = 1), ICOS (n = 1), IGHM (n = 1), and TCF3 (n = 1) genes. Three novel variants were described in the BTK (p.G414W), ICOS (p.G60*), and IGHM (p.S19*) genes. We performed Sanger sequencing to validate pathogenic variants and check for allelic segregation in the family. Targeted NGS panel sequencing can be beneficial as a suitable diagnostic modality for diagnosing well-known monogenic PAD diseases (only 2-10% of PADs); however, screening only the coding regions of the genome may not be adequately powered to solve the pathogenesis of PAD in all cases. Deciphering the regulatory regions of the genome and better understanding the epigenetic modifications will elucidate the molecular basis of complex PADs. Istanbul University ; Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) ; Istanbul Bilgi University

Human inborn errors of immunity (IEI) are a group of 485 distinct genetic disorders affecting children and adults. Signs and symptoms of IEI are heterogeneous, and accurate diagnosis can be challenging and depends on the available human expertise and laboratory resources. The Middle East and North Africa (MENA) region has an increased prevalence of IEI because of the high rate of consanguinity with a predominance of autosomal recessive disorders. This area also exhibits more severe disease phenotypes compared with other regions, probably due to the delay in diagnosis. The MENA-IEI registry network has designed protocols and guidelines for the diagnosis and treatment of IEI, taking into consideration the variable regional expertise and resources. These guidelines are primarily meant to improve the care of patients within the region, but can also be followed in other regions with similar patient populations.

The life span of patients with primary and secondary immunodeficiencies has increased due to recent advances in diagnostic and therapeutic strategies. Primary immune deficiencies (PIDs) are genetic disorders that predispose patients to frequent infections, autoimmunity and malignancies. Genomic instability due to defective DNA repair processes and other unknown mechanisms in patients with PID leads to an enhanced risk of cancer. PIDs were originally described as rare diseases occurring only in infants and young children, which are associated with severe clinical symptoms. However, advances in gene sequencing technologies, have revealed that they are much more common than originally appreciated and are present in older children, adolescents, and adults. After infection, malignancy is the most prevalent cause of death in both children and adults with PIDs. The overall risk of developing cancer in patients with PID is estimated to range from 4.7 to 5.7 percent. A 1.4 to 1.6-fold excess relative risk of cancer has been reported for PIDs. Increasing awareness among physicians regarding PID and cancer may lead to earlier diagnosis which may decrease morbidity and mortality. In this paper, we review the various categories of PIDs in children and highlight their association with various malignancies. MEDLINE was searched to identify articles for inclusion. Three authors have independently screened literature search results from MEDLINE and abstracted data from studies dealing with cancers of children among primary immune deficiencies.

BACKGROUND Most patients with organic acidemia suffer from recurrent infections. Although neutropenia has been reported in multiple studies, other components of the immune system have not been evaluated thoroughly. This study was conducted to assess the immune status of patients with organic acidemia (OA). METHODS Thirty-three patients with OA followed up in Istanbul University-Cerrahpasa, Cerrahpasa School of Medicine, Nutrition and Metabolism Department and a total of 32 age and sex matched healthy controls were enrolled to the study. The demographic and clinical data were recorded retrospectively from patient files. Complete blood count, immunoglobulins and lymphocyte immunophenotyping were recorded prospectively in a symptom (infection) free period. RESULTS Among 33 patients enrolled to the study, twenty-one (88%) were diagnosed as methylmalonic acidemia (MMA), 10 (33%) as propionic acidemia (PA) and 2 (6,6%) as isovaleric acidemia (IVA). The mean age of the patients with OA and healthy subjects were 5.89±4.11 years and 5.34±4.36, respectively (p=0.602). Twenty-nine (88%) of the patients had experienced frequent hospital admission, 13 (39%) were admitted to pediatric intensive care unit (PICU), 18 (55%) suffered from sepsis. Naive helper T cells and recent thymic emigrants were significantly lower in OAs (p

Purpose Severe combined immunodefciency (SCID) is one of the most severe forms of inborn errors of immunity characterized by absence or loss of function in T cells. The long-term outcomes of all forms of SCID have been evaluated in a limited number of studies. We aimed to evaluate the pre- and post-transplant manifestations of SCID patients and determine the factors afecting the survival of patients. Methods We included 54 SCID patients (classical SCID, Omenn syndrome, atypical SCID (AS)) in this study. We evaluated the clinical presentation, infections, and outcome of hematopoietic stem cell transplantation (HSCT). Lymphocyte subsets and T-cell receptor (TCR) repertoire were analyzed by fow cytometry. Results The median age at diagnosis was 5 (range: 3–24) months and follow-up time was 25 (range: 5–61) months. Symptom onset and diagnostic ages were signifcantly higher in AS compared to others (p = 0.001; p < 0.001). The most common SCID phenotype was T-B-NK +, and mutations in recombination-activating genes (RAG1/2) were the prominent genetic defect among patients. The overall survival (OS) rate was 83.3% after HSCT, higher than in nontransplanted patients (p =0.001). Peripheral blood stem cell sources and genotypes other than RAG had a signifcant favorable impact on CD4+ T cells immune reconstitution after transplantation (p=0.044, p=0.035; respectively). Gender matching transplantations from human leukocyte antigen (HLA)–identical and non-identical donors and using peripheral blood stem cell source yielded higher B-cell reconstitution (p=0.002, p=0.028; respectively). Furthermore, receiving a conditioning regimen provided better B-cell reconstitution and chimerism (p = 0.003, p = 0.001). Post-transplant TCR diversity was sufcient in the patients and showed an equal distribution pattern as healthy controls. The OS rate was lower in patients who underwent transplant with active infection or received stem cells from mismatched donors (p=0.030, p=0.015; respectively). Conclusion This study identifes diagnostic and therapeutic approaches predictive of favorable outcomes for patients with SCID.

Patients with autosomal recessive protein kinase C delta (PKC delta) deficiency suffer from childhood-onset autoimmunity, including systemic lupus erythematosus. They also suffer from recurrent infections that overlap with those seen in patients with chronic granulomatous disease (CGD), a disease caused by defects of the phagocyte NADPH oxidase and a lack of reactive oxygen species (ROS) production. We studied an international cohort of 17 PKC delta-deficient patients and found that their EBV-B cells and monocyte-derived phagocytes produced only small amounts of ROS and did not phosphorylate p40(phox) normally after PMA or opsonized Staphylococcus aureus stimulation. Moreover, the patients' circulating phagocytes displayed abnormally low levels of ROS production and markedly reduced neutrophil extracellular trap formation, altogether suggesting a role for PKC delta in activation of the NADPH oxidase complex. Our findings thus show that patients with PKC delta deficiency have impaired NADPH oxidase activity in various myeloid subsets, which may contribute to their CGD-like infectious phenotype. Yale Center for Mendelian Genomics - National Human Genome Research Institute [UM1HG006504]; National Institute of Allergy and Infectious DiseasesUnited States Department of Health & Human ServicesNational Institutes of Health (NIH) - USANIH National Institute of Allergy & Infectious Diseases (NIAID) [5R01AI089970, 5R37AI095983, R01AI127564-01]; National Center for Research ResourcesUnited States Department of Health & Human ServicesNational Institutes of Health (NIH) - USANIH National Center for Research Resources (NCRR); National Center for Advancing Translational Sciences of the National Institutes of HealthUnited States Department of Health & Human ServicesNational Institutes of Health (NIH) - USANIH National Center for Advancing Translational Sciences (NCATS) [8UL1TR001866]; Rockefeller University; St. Giles Foundation; INSERMInstitut National de la Sante et de la Recherche Medicale (Inserm)European Commission; University of Paris; French Foundation for Medical ResearchFondation pour la Recherche Medicale [EQU201903007798]; Integrative Biology of Emerging Infectious Diseases Laboratory of Excellence [ANR-10-LABX-62-IBEID]; SCOR Corporate Foundation for Science; French National Research Agency (ANR) under the Investments for the future programFrench National Research Agency (ANR) [ANR-10-IAHU-01]; ANR-IFNPHOX [ANR-13-ISV3-0001-01]; ANR-GENMSMDFrench National Research Agency (ANR) [ANR-16-CE17-0005-01]; ANR-GENCMCD [ANR-11-BSV3-005-01]; ANR-HGDIFDFrench National Research Agency (ANR) [ANR-14-CE15-0006-01]; Bettencourt Schueller Foundation; International PhD program of the Imagine Institute; Japanese Foundation; EURO-CMC project [ANR-14-RARE-0005-02]; Societe Nationale Francaise de Medecine Interne (Bourse Marcel Simon); INSERM PhD program for medical doctors (poste d'accueil INSERM); Fulbright grant (Franco-American commission); MD-PhD program of Imagine Institute; Consejo Nacional de Ciencia y Tecnologa National PhD Fellowship Program; National Institute for Health Research Biomedical Research CentreNational Institute for Health Research (NIHR); Great Ormond Street Hospital Charity; Deutsche Forschungsgemeinschaft under Germany's Excellence StrategyGerman Research Foundation (DFG) [EXC 2155, 390874280]; REBIRTH Center for Translational Regenerative Medicine through the State of Lower Saxony [MWK: ZN3440] This paper is dedicated to the memory of Prof. Asghar Agha-mohammadi, who passed away in November 2020, and made immense contributions to the understanding and treatment of primary immunodeficiencies. We thank all patients, their relatives, and the treatment teams for their cooperation in this study. We thank all the members of the Laboratory of Human Genetics of Infectious Diseases for helpful discussions. We also thank Christine Rivalain, Cecile Pa-tissier, Lazaro Lorenzo-Diaz, Dominick Papandrea, Dana Liu, and Yelena Nemirovskaya for administrative assistance and Gaspard Kerner for statistical advice. We thank the Necker Institute Imaging Facility for technical advice. The graphical abstract was created with BioRender.com under subscription. This research was supported by the Yale Center for Mendelian Genomics funded by the National Human Genome Research Insti-tute (UM1HG006504) . The Howard Hughes Medical Institute lab-oratory was funded in part by the National Institute of Allergy and Infectious Diseases (grants 5R01AI089970, 5R37AI095983, and R01AI127564-01) , the National Center for Research Resources, and the National Center for Advancing Translational Sciences of the National Institutes of Health (grant 8UL1TR001866 for J-L. Casa-nova) , the Rockefeller University, the St. Giles Foundation, INSERM, the University of Paris, the French Foundation for MedicalResearch (EQU201903007798) , the Integrative Biology of Emerging Infectious Diseases Laboratory of Excellence (ANR-10-LABX-62-IBEID) , the SCOR Corporate Foundation for Science, and the French National Research Agency (ANR) under the Investments for the future program (grant ANR-10-IAHU-01) , ANR-IFNPHOX (grant ANR-13-ISV3-0001-01 for J. Bustamante) , ANR-GENMSMD (grant ANR-16-CE17-0005-01 for J. Bustamante) , ANR-GENCMCD (grant ANR-11-BSV3-005-01 for A. Puel) , and ANR-HGDIFD (grant ANR-14-CE15-0006-01 for J. Bustamante) . A-L. Neehus was sup-ported by the Bettencourt Schueller Foundation and the Interna-tional PhD program of the Imagine Institute, K. Moriya by a Japanese Foundation for Pediatric Research fellowship grant and EURO-CMC project (grant ANR-14-RARE-0005-02 for J. Bustamante) , R. Levy by the Societe Nationale Francaise de Medecine Interne (Bourse Marcel Simon) , the INSERM PhD program for medical doctors (poste d'accueil INSERM) , and the Fulbright grant (Franco-American commission) , T. Le Voyer by the Bettencourt Schueller Foundation and the MD-PhD program of Imagine Institute, and A. Nieto-Patlan by the Consejo Nacional de Ciencia y Tecnologa Na-tional PhD Fellowship Program. All research at the Great Ormond Street Hospital National Health Service Foundation Trust is sup-ported by the National Institute for Health Research Biomedical Research Centre. P.A. Brogan also acknowledges support from the Great Ormond Street Hospital Charity. N. Lachmann acknowledges support from the Deutsche Forschungsgemeinschaft under Ger-many's Excellence Strategy-EXC 2155-project number 390874280 and the REBIRTH Center for Translational Regenerative Medicine funded through the State of Lower Saxony (MWK: ZN3440) . Author contributions: A-L. Neehus, J-L. Casanova, A. Puel, and J. Bustamante conceived and designed the study. A-L. Neehus, K. Moriya, T. Le Voyer, A. Nieto-Patlan, R. Levy, M. Roynard, K. Haake, M. Migaud, and K. Dorgham performed the experiments. A. ozen, E. Karakoc-Aydiner, S. Baris, A. Yildiran, E. Altundag, F. Dogu, S. Has-kologlu, E. Ince, G. Uzel, A. Kiykim, K. Boztug, M.R. Roderick, M. Shahrooei, P.A. Brogan, H. Abolhassani, G. Hancioglu, N. Parvaneh, A.; Belot, and A. Ikinciogullari were the treating physicians respon-sible for clinical diagnosis, deep phenotyping, sample collection, and patient follow-up. G. Gorochov, L. Abel, N. Lachmann, J. El-Benna, and A. Belot provided conceptual advice. A-L. Neehus, J-L. Casanova, A. Puel, and J. Bustamante analyzed the results and wrote the man-uscript. All authors revised the manuscript and approved the final manuscript as submitted. Disclosures: P.A. Brogan reported personal fees from Sobi, No-vartis, Roche, and GSK, and grants from Sobi outside the sub-mitted work. No other disclosures were reported.

Elucidating the molecular basis of immunodeficiency diseases is a powerful approach to discovering new immunoregulatory pathways in humans. Here we report 10 affected individuals from 4 families with a new immunodeficiency disease comprising of severe progressive lymphopenia, autoimmunity, immunodeficiency, and liver disease due to recessive loss of function variants in “GTPase of immunity-associated proteins” protein 5 (GIMAP5). We show that the disease involves the progressive loss of naïve T lymphocytes and a corresponding increase in antigen-experienced, but poorly functional and replicatively senescent T cells. In vivo treatment of Gimap5-deficient mice with rapamycin (an inhibitor of mTORC1) significantly restores the fraction of naïve T lymphocytes. Furthermore, a GIMAP5-deficient human patient who was treated with rapamycin (sirolimus) showed a remarkable reduction in spleen/lymph node size. Together, these observations reveal that GIMAP5 plays a critical role in lymphocyte metabolism which is essential for senescence prevention and immune competence, suggesting that an inhibitor of mTORC1 could be a valuable clinical intervention in treating patients deficient for GIMAP5.

Hyper-IgE syndrome (HIES) patients may share many features observed in severe atopic dermatitis (SAD), making a diagnostic dilemma for physicians. Determining clinical and laboratory markers that distinguish both disorders could provide early diagnosis and treatment. We analyzed patients (DOCK8 deficiency:14, STAT3-HIES:10, SAD:10) with early-onset SAD. Recurrent upper respiratory tract infection and pneumonia were significantly frequent in HIES than SAD patients. Characteristic facial appearance, retained primary teeth, skin abscess, newborn rash, and pneumatocele were more predictable for STAT3-HIES, while mucocutaneous candidiasis and Herpes infection were common in DOCK8 deficiency, which were unusual in SAD group. DOCK8-deficient patients had lower CD3+ and CD4+T cells with a senescent phenotype that unique for this form of HIES. Both DOCK8 deficiency and STAT3-HIES patients exhibited reduced switched memory B cells compared to the SAD patients. These clinical and laboratory markers are helpful to differentiate HIES from SAD patients. WOS:000613283300013 33301882 Q3

Background Genetic deficiencies of immune system, referred to as inborn errors of immunity (IEI), serve as a valuable model to study human immune responses. In a multicenter prospective cohort, we evaluated the outcome of SARS‐CoV‐2 infection among IEI subjects and analyzed genetic and immune characteristics that determine adverse COVID‐19 outcomes. Methods We studied 34 IEI patients (19M/15F, 12 [min: 0.6‐max: 43] years) from six centers. We diagnosed COVID‐19 infection by finding a positive SARS‐CoV‐2 PCR test (n = 25) and/or a lung tomography scoring (CORADS) ≥4 (n = 9). We recorded clinical and laboratory findings prospectively, fitted survival curves, and calculated fatality rates for the entire group and each IEI subclass. Results Nineteen patients had combined immune deficiency (CID), six with predominantly antibody deficiency (PAD), six immune dysregulation (ID), two innate immune defects, and one in the autoinflammatory class. Overall, 23.5% of cases died, with disproportionate fatality rates among different IEI categories. PAD group had a relatively favorable outcome at any age, but CIDs and IDs were particularly vulnerable. At admission, presence of dyspnea was an independent risk for COVID‐related death (OR: 2.630, 95% CI; 1.198–5.776, p, 34 IEI patients aged between 0.6 and 43 years, eight patients (23.5%) succumbed to COVID‐19, indicating a highly vulnerable condition to COVID‐19. Laboratory markers associated with mortality included elevated acute phase reactants, ferritin, troponin T, TLS, and reduced ALC levels, albumin, and baseline IgG. Coughing, dyspnea, CORADS category 4–6, and negative SARS‐CoV‐2 PCR at admission were among the predictors of lethal outcome.

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Purpose: Recently, a new form of congenital neutropenia that is caused by germline biallelic loss-of-function mutations in the SMARCD2 gene was described in four patients. Given the rarity of the condition, the clinical spectrum of the disease has remained elusive. We here report a new patient with a novel frameshift mutation and compare our patient with the previously reported SMARCD2-mutant patients, aiming to provide a more comprehensive understanding of the natural course of the disease. Methods: Clinical and laboratory findings of all reported patients were reviewed. Next-generation sequencing was performed to identify the causative genetic defect. Data on the hematopoietic stem cell transplantation including stem cell sources, conditioning regimen, engraftment, graft-versus-host disease, and infections were also collected. Results: An 11-year-old female patient had a variety of infections including sepsis, deep tissue abscesses, otitis, pneumonia, gingivitis, and diarrhea since infancy. A novel homozygous mutation in SMARCD2 (c.93delG, p.Ala32Argfs*80) was detected. Bone marrow examination showed hypocellularity and decreased neutrophils with diminished granules and myeloid dysplasia, but no blast excess as in previously reported patients. The neutropenia was non-responsive even to higher doses of granulocyte colony-stimulating factor (G-CSF); therefore, the patient was transplanted at 10 years of age from a HLA-A allele–mismatched unrelated donor using a reduced toxicity conditioning regimen and recovered successfully. Compared with the previous four cases, our patient showed longer survival before transplantation without blastic transformation. Conclusion: Distinctive myeloid features and long-term follow-up including therapy options are presented for the newly described case of SMARCD2 deficiency. This disorder is apparent at infancy and requires early transplantation due to the unrelenting disease course despite conventional therapy. WOS:000575728800002 33025377 Q1

Background Heterozygous relatives of ataxia-telangiectasia (AT) patients are at an increased risk for certain AT-related manifestations. We also show that there is an increase of infection frequency in parents of AT patients. Thus, we hypothesized that the parents might exhibit immune alterations similar to their affected children. Methods Lymphocyte phenotyping to enumerate T- and B-cell subsets was performed. Functional analyses included in vitro quantified gamma-H2AX, poly (ADP-ribose) polymerase (PARP) and caspase-9 proteins. Chromosomal instability was determined by comet assay. Results We analyzed 20 AT patients (14F/6M), 31 parents (16F/15M), and 35 age-matched healthy controls. The AT patients- parents exhibited low frequency of naive CD4(+)T- (n = 14, 45%) and recent thymic emigrants (n = 11, 35%) in comparison with the age-matched healthy donors. Interestingly, parents with low naive T cells also demonstrated high rate of recurrent infections (9/14, 64%). In comparison with age-matched controls, parents who had recurrent infections and low naive T cells showed significantly higher baseline gamma-H2AX levels and H2O2-induced DNA damage as well as increased cleaved caspase-9 and PARP proteins. Conclusion Parents of AT patients could present with recurrent infections and display cellular defects that mimic AT patients. The observed immunological changes could be associated with increased DNA double-strand breaks.

Background: Urticaria can be the only sign of a food allergy or can be seen together with other signs and symptoms of a food allergy. Objective: To determine the demographic, etiologic, and clinical features of food-induced acute urticaria in childhood. Methods: Patients suspected of food-induced acute urticaria were included in this prospective cross-sectional multicenter study. Results: Two hundred twenty-nine urticaria cases were included in this study. Seventeen patients who did not meet the inclusion criteria of the study were excluded. Of the 212 included cases, 179 (84.4%) were diagnosed with definitive food-induced acute urticaria. The most common foods causing acute urticaria were cow’s milk, hen’s eggs, and nuts in 56.4, 35.2, and 19% of cases, respectively. The positive predictive value of a history of milk-induced acute urticaria together with a milk-specific IgE >5 kU/L for cow’s milk-induced acute urticaria was 92% (95% CI: 81–96%). A history of cow’s milk-induced and/or hen’s egg-induced acute urticaria was consistent with a definitive diagnosis of food-induced urticaria (Chen’s kappa: 0.664 and 0.627 for milk and eggs, respectively). Urticaria activity scores were higher in patients with food-induced acute urticaria (p = 0.002). Conclusion: Cow’s milk, hen’s eggs, and nuts were the most common allergens in the etiology of childhood food-induced acute urticaria. Although the urticaria activity score provides guidance for diagnosis, an oral food challenge is often essential for the definitive diagnosis of a patient with a history of food-induced acute urticaria.

Background TRAF3 interacting protein 2 (TRAF3IP2) (Act1) is an adapter protein that interacts with IL-17R via its similar expression to fibroblast growth factor genes and IL-17R domain and coordinates 2 separate proinflammatory pathways following IL-17 cytokine stimulation. Objective We sought to elucidate the immunologic consequences of TRAF3IP2 homozygous mutations to improve treatments for immunodeficiency patients with chronic mucocutaneous candidiasis. Methods We describe 2 patients presenting with chronic mucocutaneous candidiasis who harbor biallelic nonsense mutations in TRAF3IP2. The cellular and molecular features of this genetic defect were assessed using in vitro cytokine assays and protein analysis. Results We show that the homozygous mutation causes complete loss of protein expression. We also show that the absence of TRAF3IP2 was associated with a defective response to combined IL-2/IL-25 (IL-17E) stimulation. Conclusions Failure to initiate normal signaling downstream of IL-17R engagement likely contributes to the patients’ recurrent fungal infections. These findings add to our molecular understanding of genetic defects affecting this critical pathway of antifungal immunity.

Background Primary immunodeficiency diseases (PID) are characterized by the occurrence of frequent infections and are caused by many genetic defects. Hematopoietic stem cell transplantation (HSCT) is the only curative treatment option for the majority of PID. As a Pediatric Hematology-Oncology-Immunology Transplantation Unit, we wanted to present our HSCT experience regarding treatment of primary immunodeficiency diseases. Methods 58 patients were included in the study between January 2014 and June 2019. We searched 9/10 or 10/10 matched-related donor (MRD) firstly, in the absence of fully matched-related donor. We screened matched unrelated donor (MUD) from donor banks. MRD was used in 24 (41.3%) patients, MUD in 20 (34.4%) patients, and haploidentical donors in 14 (24.1%) patients. Demographic data, HSCT characteristics, and outcome were evaluated. While 16 patients had severe combined immunodeficiency (SCID), the remaining was non-SCID. Results Of the 58 patients, 38 were male and 20 were female. Median age at transplantation was 12 months (range: 2.5-172 months). Combined immunodeficiencies consisted 67.2% of patients. Mean follow-up time was 27 months (6 months-5 years). Median neutrophil, lymphocyte, and thrombocyte engraftment days were similar in comparison of both donor type and stem cell source. The most common complication was acute GvHD in 15 (25.8%) patients. In total, five patients (31%) belonging to the SCID group and 10 patients (23.8%) belonging to the non-SCID group died. Our total mortality rate was 15 (25.8%) in all patients. Conclusions We would like to present our HSCT experiences as a pediatric immunology transplantation center. Existing severe infections before transplantation period, BCGitis, and CMV are important issues of transplantation in Turkey. However, the follow-up time is shorter than some studies, our results regarding complications and survival are similar to previous reports. WOS:000658020800001 34092004 Q4

Background Chronic granulomatous disease (CGD) is characterized by defective microbial killing due to mutations affecting subunits of the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase complex. Definitive genetic identification of disease subtypes may be delayed or not readily available. Objective Sought to investigate the role of intracellular staining of NADPH oxidase enzyme subunits in predicting the respective genetic defects in patients with CGD and carriers. Methods Thirty-four patients with genetically inherited CGD, including 12 patients with X-linked CGD (gp91phagocyte oxidase (phox) deficiency due to cytochrome b-245, beta polypeptide [CYBB] mutations) and 22 patients with autosomal-recessive CGD (p22phox, p47phox, and p67phox deficiency due to cytochrome b-245, alpha polypeptide [CYBA], neutrophil cytosolic factor 1 [NCF1] and NCF2 mutations, respectively) were recruited from different immunology centers and followed up prospectively. Dihydrorhodamine testing and NADPH oxidase subunit expression in white blood cells were determined by flow cytometry. Results gp91phox and p22phox defects, which result in simultaneous loss of both proteins due to their complex formation, were differentiated only by comparative analysis of patients' and mothers' intracellular staining. p47phox and p67phox protein expression was almost undetectable in patients compared with carrier mothers and healthy controls. The expression values of the respective subunits were found to be significantly higher in all controls as compared with carrier mothers, which in turn were higher than those of patients. Conclusions Analysis of NADPH oxidase enzyme subunits by flow cytometry in patients and carriers is useful in the rapid prediction of the genetic defect of patients with CGD, thus guiding targeted sequencing and aiding in their early diagnosis.

Aim In the presence of food allergies, especially egg allergies, primary physicians in Turkey avoid vaccine administration and refer children to a hospital setting. We aimed to evaluate children who had allergies or suspected allergies and were referred to our Well Child Clinic in a university hospital for vaccination. Material and methods Charts of all children referred to our clinic due to concerns for allergies in the last two years, were reviewed. Demographic data, laboratory evaluation and reactions after immunization were recorded. Results A total of 122 children with or without a confirmed diagnosis of allergies were referred by primary physicians. In the history, 50 children (43.5%) had reactions with egg, 42 (36.5%) had reactions with multiple foods, nine (7.8%) had reactions with milk and seven (6.1%) had reactions with a previous vaccination. The most common reaction was rash (n=89, 86.4%). Nine children reported anaphylaxis. Skin testing or serum allergen specific IgE measurement revealed that 66 (54.1%) children had sensitization to egg white and 25 (20.5%) had sensitization to egg yolk. Most children (n=87, 71.9%) were referred for all the 12th-month vaccines, and 21 children were referred only for the measles-mumps-rubella vaccine (n=21, 17.4%). The median delay time in the administration of the measles-mumps-rubella vaccine was 20.0 (interquartile range: 8.7-41.2) days. No reaction was observed except for one child reporting a slight rash several hours after vaccination. Conclusion Egg allergy was the most common barrier of vaccine administration in children referred from family physicians. Given the absence of any reactions, we support the administration of the measles-mumps-rubella vaccine in primary care settings to prevent delays in national vaccine schedule.

The original published version of this article contained a mistake in one of the affiliations. The correct affiliation of author Manolya Kara (7) should read: Istinye University Faculty of Medicine, VM MedicalPark Pendik Hospital, Pediatric Infectious Diseases Clinic, Istanbul, Turkey The original article has been corrected. © 2021, Springer Science+Business Media, LLC, part of Springer Nature. 10.1007/s12026-021-09248-7 WOS:000708817100001 34668146 Q3

A cardinal feature of COVID-19 is lung inflammation and respiratory failure. In a prospective multi-country cohort of COVID-19 patients, we found that increased Notch4 expression on circulating regulatory T (Treg) cells was associated with disease severity, predicted mortality, and declined upon recovery. Deletion of Notch4 in Treg cells or therapy with anti-Notch4 antibodies in conventional and humanized mice normalized the dysregulated innate immunity and rescued disease morbidity and mortality induced by a synthetic analog of viral RNA or by influenza H1N1 virus. Mechanistically, Notch4 suppressed the induction by interleukin-18 of amphiregulin, a cytokine necessary for tissue repair. Protection by Notch4 inhibition was recapitulated by therapy with Amphiregulin and, reciprocally, abrogated by its antagonism. Amphiregulin declined in COVID-19 subjects as a function of disease severity and Notch4 expression. Thus, Notch4 expression on Treg cells dynamically restrains amphiregulin-dependent tissue repair to promote severe lung inflammation, with therapeutic implications for COVID-19 and related infections., Graphical abstract, Harb, Benamar, et al. find that interleukin-6 increases Notch4 expression on lung regulatory T cells, which, in turn, restrains production of the tissue repair cytokine amphiregulin and promotes severe lung inflammation. Their findings have implications for treatment of COVID-19 and other respiratory viral infections.

Objective Flow cytometric quantification of in vitro basophil activation can be quite performant and reliable tool to measure IgE-dependent allergen-specific responses in allergic patients. Current study aimed to evaluate the clinical relevance of basophil activation test (BAT) for the diagnosis of pediatric grass pollen and house dust mite (HDM) allergies. Methods Forty-seven patients suffering from allergic rhinitis with HDM and grass pollen co-sensitization with clinical history of allergic rhinitis and/or asthma and 15 non-allergic healthy subjects were enrolled. BAT was determined by flow cytometry upon double staining with anti-IgE/anti-CD63 mAb. Results Regarding HDM with cut-off point greater than 12.5% for CD63 + basophils sensitivity and specificity of the BAT were 90% and 73%, with positive predictive value (PPV) and negative predictive value (NPV) as 0.70 and 0.91, respectively. The analysis of concordance of being either allergic or healthy in comparison to BAT results for HDM revealed a substantial concordance (κ index = 0.61, p Conclusion Our findings concluded that BAT is reliable technique in the diagnosis of sensitization to grass pollen and HDM. The sensitivity of BAT in pollen allergic children was found to be remarkably higher in our cohort compared to other studies.