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Severe combined immunodeficiency is an inborn error of immunity characterized by impairments in the numbers and functions of T and B lymphocytes due to various genetic causes, and if it remains untreated, patients succumb to infections during the first 2 years of life. Purpose and Methods: This study reported retrospective data from 72 infants diagnosed with SCID including their major clinical features, HSCT characteristics, and outcomes over a 20-year period (1997–2017). Results: Sixty-one of 72 SCID patients in the study underwent HSCT from 1997 to 2017. Median ages at the time of diagnosis and transplantation were 3.5 months and 5 months, respectively. Consanguinity was present in 68% of the patients, and T − B − NK + phenotype was predominantly identified. The overall survival was 80.3% over a 20-year period. However, the patients transplanted during an active infection had a lower survival rate of 73.9% compared to 100% for patients transplanted infection-free or with a previous infection that had resolved. The survival rate was significantly higher among recipients of HLA-identical transplants (92.9%), compared to recipients of mismatched related transplants (70%). The overall survival increased from 50 (1997–2006) to 85% (2007–2017) during the last 10 years. Conclusions: This is one of the largest single-center studies in Turkey with extensive experience about SCID patients. Early diagnosis of SCID patients before the onset of an infection and early transplantation are shown to be extremely important factors affecting the outcome and increasing the survival regardless of the donor type based on the results of this study. WOS:000659780700002 34114123 Q1

Giriş-Amaç: Lökosit Adezyon Defekti (LAD), lökositlerin adezyon, migrasyon, kemotaksis ve ekstravazasyonunda rol alan moleküllerin eksikliklerine bağlı gelişen, nadir görülen, otozomal resesif katılımlı, üç ayrı tipi olan (LAD-I, LAD-II ve LAD-III) bir primer immün yetmezlik hastalığıdır. Tekrarlayan bakteriyel, fungal enfeksiyonlar ve lökositoz ile karakterizedir. Bu çalışmada, LAD-I ve LAD-III tanısı konulan hastaların klinik, immünolojik özelliklerinin, tedavi ve hematopoietik kök hücre nakli (HKHN) sonuçlarının değerlendirilmesi amaçlanmıştır. Gereç ve Yöntem: Bu çalışmaya, Mart 2008 ile Haziran 2018 tarihleri arasında bölümümüzde LAD tanısı konulan, takip ve tedavileri yapılan 14 hasta dâhil edildi. Hastaların demografik, klinik, laboratuvar özellikleri, genetik mutasyonları, izlemleri ve HKHN sonuçları geriye dönük olarak değerlendirildi. Bulgular: Hastaların 12’si LAD-I (%86), 2’si LAD-III (%14) idi. Tüm hastalarda (9 kız/5 erkek) akraba evliliği, 3 hastada benzer şikâyetlerle kaybedilen kardeş öyküsü vardı. Göbek bağının düşmesinde gecikme 13/14(%93), omfalit 12/14(%86), nekrotizan cilt yaraları 9/14(%64), pnömoni 5/14(%36), gingivit 4/14(%29) ve moniliazis 4/14(%29) en sık rastlanan klinik bulgulardı. Tüm hastalarda lökositoz ve nötrofili mevcuttu. CD18 ekspresyonu %2’den düşük olan 10 hasta ağır LAD-I, CD18 ekspresyonları %16 ve %19 olan 2 hasta ise hafif-orta ağırlıkta LAD-I olarak değerlendirildi. 8 hastada mutasyonlar genetik analiz ile gösterildi. Kardeş olan 3 hastada ITGB2 geninde yeni bir mutasyon saptandı. Nakil yapılmayan hastalar, tekrarlayan cilt ve solunum enfeksiyonları nedeniyle çok kez ayaktan veya hastanede yatarak tedavi aldı. En sık rastlanan enfeksiyon ajanları S.aureus ve E.faecium oldu. 6 hastaya tam uyumlu aile içi ve 1 hastaya tam uyumlu akraba dışı donörden HKHN yapıldı. Tüm hastalarda engrafman sağlandı ve ciddi bir komplikasyon izlenmedi. LAD-III tanılı bir olgu nakil yapılamadan kanama nedeniyle kaybedildi. Tüm hastalarda hayatta kalma oranı %93 iken HKHN yapılanlarda %100 oldu. Sonuç: Göbek bağının düşmesinde gecikme, tekrarlayan cilt ve mukoza enfeksiyonları olan ve lökositozla gelen her olguda LAD tanısı akla gelmelidir. Hematopoetik kök hücre nakli bu hastalar için küratif tedavi yöntemidir.AbstractIntroduction-AimLeukocyte Adhesion Deficiency (LAD) is a rare autosomal recessive primary immunodeficiency that is due to deficiencies of molecules involved in adhesion, migration, chemotaxis and extravasation of leukocytes with three different types (LAD-I, LAD-II, LAD-III). It is characterised by recurrent bacterial, fungal infections and leucocytosis. In this study, it is aimed to evaluate clinical, immunological features, treatment and follow-up of patients diagnosed with LAD-I and III.Material-Method In this study there were 14 LAD patients who were diagnosed, treated and followed up in our department between March 2008- June 2018. The demographic, clinical, laboratory features, genetic mutations, follow-up and hematopoietic stem cell transplantation (HSCT) results of patients were evaluated retrospectively. Results There were 12 (86%) patients with LAD-I, and 2 (14%) of them were LAD-III. All patients (9 female/5 male) had consanguinity, 3 patients had history of sibling death with similar complaints. The most common clinical findings were 13 (93%) delayed umbilical cord separation, 12 (86%) omphalitis, 9 (64%) necrotising skin wounds, 5 (36%) pneumonia, 4 (29%) gingivitis and 4 (29%) moniliasis. All patients had neutrophilia and leucocytosis. There were 10 severe LAD-I patients with CD18 expression lower than 2% and 2 mild-moderate LAD-I patients with CD18 expression 16% and 19%. Mutations were demonstrated in 8 patients by genetic analysis. A new mutation in the ITGB2 gene was detected in 3 sibling patients. Patients who were not transplanted received multiple outpatient/inpatient treatments due to recurrent skin and respiratory infections. S.aureus and E.faecium were most common infectious agents. HSCT was performed in 6 patients from full matched related donors and in 1 patient from full matched unrelated donor. Engraftment was achieved in all patients without serious complications. One patient with LAD-III died due to bleeding before transplantation. While the survival rate was 93% in all patients, it was 100% in HSCT patients. ConclusionLAD diagnosis must be considered in patients with delayed umbilical cord separation, recurrent skin and mucosal infections and leucocytosis. Hematopoietic stem cell transplantation is a curative treatment for these patients.

Objective: To evaluate the characteristics of the patients who were followed-up with the diagnosis of ataxia telangiectasia (AT) and to assess the relationship between the hyper IgM (HIGM) phenotype and their prognosis. Materials and Methods: From 2007 to 2019, the study included 68 patients aged 3-35 years who were followed-up with the diagnosis of AT. We retrospectively evaluated the clinical and immunological characteristics and follow-up results. Results: There were 36 girls and 32 boys with a median follow-up of 10 years (1-12 years). The most common complaints upon admission were unsteady walk in 87%, infection in 6%, presence of a family history in 6%, and intracranial mass in 1%. The marriage was consanguineous in 85% of the parents. Ataxia was seen in 100% of the patients, telangiectasia in 97%, and immune deficiency in 88%. Bronchiectasis was observed in 23.5% of the patients, chronic diarrhea in 19%, lymphoproliferation in 15%, malignancy in 10%, autoimmunity in 10%, liver failure in 6%, and granulomatous skin lesions in 6%. Thirteen patients (19%) died during follow-up. The HIGM phenotype was identified in 31% of the patients. Recurrent upper and lower respiratory tract infections (p=0.004 and p

Helios, a member of the Ikaros family of transcription factors, is predominantly expressed in developing thymocytes, activated T cells, and regulatory T cells (T-regs). Studies in mice have emphasized its role in maintenance of T-reg immunosuppressive functions by stabilizing Foxp3 expression and silencing the Il2 locus. However, its contribution to human immune homeostasis and the precise mechanisms by which Helios regulates other T cell subsets remain unresolved. Here, we investigated a patient with recurrent respiratory infections and hypogammaglobulinemia and identified a germline homozygous missense mutation in IKZF2 encoding Helios (p.Ile325Val). We found that Helios(I325V) retains DNA binding and dimerization properties but loses interaction with several partners, including epigenetic remodelers. Whereas patient T-regs showed increased IL-2 production, patient conventional T cells had decreased accessibility of the IL2 locus and consequently reduced IL-2 production. Reduced chromatin accessibility was not exclusive to the IL2 locus but involved a variety of genes associated with T cell activation. Single-cell RNA sequencing of peripheral blood mononuclear cells revealed gene expression signatures indicative of a shift toward a proinflammatory, effector-like status in patient CD8(+) T cells. Moreover, patient CD4(+) T cells exhibited a pronounced defect in proliferation with delayed expression of surface checkpoint inhibitors, suggesting an impaired onset of the T cell activation program. Collectively, we identified a previously uncharacterized, germline-encoded inborn error of immunity and uncovered a cell-specific defect in Helios-dependent epigenetic regulation. Binding of Helios with specific partners mediates this regulation, which is ultimately necessary for the transcriptional programs that enable T cell homeostasis in health and disease.

Rare monogenetic diseases serve as natural models to dissect the molecular pathophysiology of the complex disease traits. Rheumatologic disorders by their nature are considered complex diseases with partially genetic origin, as illustrated by their heterogeneous genetic background and variable phenotypic presentation. Recent advances in genetic technologies have helped uncover multiple variants associated with disease susceptibility; however, a precise understanding of genotype–phenotype relationships is still missing. Inborn errors of immunity (IEIs), in addition to recurrent infections, may also present with autoimmune and autoinflammatory rheumatologic manifestations and have provided insights for understanding the underlying the principles of immune system homeostasis and mechanisms of immune dysregulation. This review discusses the rheumatologic manifestations in IEIs with overlapping and differentiating features in immunodeficiencies and rheumatologic disorders.

Biallelic inactivating mutations in IL21R causes a combined immunodeficiency that is often complicated by cryptosporidium infections. While eight IL-21R-deficient patients have been reported previously, the natural course, immune characteristics of disease, and response to hematopoietic stem cell transplantation (HSCT) remain to be comprehensively examined. In our study, we have collected clinical histories of 13 patients with IL-21R deficiency from eight families across seven centers worldwide, including five novel patients identified by exome or NGS panel sequencing. Eight unique mutations in IL21R were identified in these patients, including two novel mutations. Median age at disease onset was 2.5 years (0.5–7 years). The main clinical manifestations were recurrent bacterial (84.6%), fungal (46.2%), and viral (38.5%) infections; cryptosporidiosis-associated cholangitis (46.2%); and asthma (23.1%). Inflammatory skin diseases (15.3%) and recurrent anaphylaxis (7.9%) constitute novel phenotypes of this combined immunodeficiency. Most patients exhibited hypogammaglobulinemia and reduced proportions of memory B cells, circulating T follicular helper cells, MAIT cells and terminally differentiated NK cells. However, IgE levels were elevated in 50% of IL-21R-deficient patients. Overall survival following HSCT (6 patients, mean follow-up 1.8 year) was 33.3%, with pre-existing organ damage constituting a negative prognostic factor. Mortality of non-transplanted patients (n = 7) was 57.1%. Our detailed analysis of the largest cohort of IL-21R-deficient patients to date provides in-depth clinical, immunological and immunophenotypic features of these patients, thereby establishing critical non-redundant functions of IL-21/IL-21R signaling in lymphocyte differentiation, humoral immunity and host defense against infection, and mechanisms of disease pathogenesis due to IL-21R deficiency. Outcome following HSCT depends on prior chronic infections and organ damage, which should thus be considered as early as possible following molecular diagnosis. Supplementary Information The online version contains supplementary material available at 10.1007/s10875-021-01031-5.

BACKGROUND: Accurate, detailed, and standardized phenotypic descriptions are essential to support diagnostic interpretation of genetic variants and to discover new diseases. The Human Phenotype Ontology (HPO), extensively used in rare disease research, provides a rich collection of vocabulary with standardized phenotypic descriptions in a hierarchical structure. However, to date, the use of HPO has not yet been widely implemented in the field of inborn errors of immunity (IEIs), mainly due to a lack of comprehensive IEI-related terms. OBJECTIVES: We sought to systematically review available terms in HPO for the depiction of IEIs, to expand HPO, yielding more comprehensive sets of terms, and to reannotate IEIs with HPO terms to provide accurate, standardized phenotypic descriptions. METHODS: We initiated a collaboration involving expert clinicians, geneticists, researchers working on IEIs, and bioinformaticians. Multiple branches of the HPO tree were restructured and extended on the basis of expert review. Our ontology-guided machine learning coupled with a 2-tier expert review was applied to reannotate defined subgroups of IEIs. RESULTS: We revised and expanded 4 main branches of the HPO tree. Here, we reannotated 73 diseases from 4 International Union of Immunological Societies-defined IEI disease subgroups with HPO terms. We achieved a 4.7-fold increase in the number of phenotypic terms per disease. Given the new HPO annotations, we demonstrated improved ability to computationally match selected IEI cases to their known diagnosis, and improved phenotype-driven disease classification. CONCLUSIONS: Our targeted expansion and reannotation presents enhanced precision of disease annotation, will enable superior HPO-based IEI characterization, and hence benefit both IEI diagnostic and research activities. ispartof: JOURNAL OF ALLERGY AND CLINICAL IMMUNOLOGY vol:149 issue:1 pages:369-378 ispartof: location:United States status: published

Biallelic mutations in the dedicator of cytokinesis 8 gene (DOCK8) cause a progressive combined immunodeficiency (CID) characterized by susceptibility to severe viral skin infections, atopic diseases, recurrent respiratory infections, and malignancy. Hematopoietic stem cell transplantation (HSCT) is only curative treatment for the disease. However, there is limited information about long‐term outcome of HSCT and its effect to protect against cancer development in DOCK8‐deficient patients. In this study, we retrospectively evaluated clinical and immunologic characteristics of 20 DOCK8‐deficient patients and outcome of 11 patients who underwent HSCT. We aimed to report the experience of our center and the result of the largest transplantation series of DOCK8 deficiency in our country. Median follow‐up time is 71 months (min‐max: 16‐172) in all patients and 48 months (min‐max: 5‐84) in transplanted patients. Atopic dermatitis (18/20), recurrent respiratory tract infections (17/20), and food allergy (14/20) were the most frequent clinical manifestations. Failure to thrive (13/20), liver problems (12/20), bronchiectasis (11/20), chronic diarrhea (10/21), and autism spectrum disorders (3/20) were remarkable findings in our series. Elevated IgE level (20/20) and eosinophilia (17/20), low IgM level (15/20), and decreased CD3+ T (10/20) and CD4+ T (11/20) cell count were prominent laboratory findings. HSCT was performed in 11 patients. All patients achieved adequate engraftment and showed improvement in their clinical and immunologic findings. Atopic dermatitis and food allergies improved in all patients, and their dietary restriction was stopped except one patient who was transplanted recently. The frequency of infections was decreased. The overall survival is 91% in HSCT‐received patients and 80% in all. HSCT at the earliest possible period with most suitable donor‐ and patient‐specific appropriate conditioning regimen and GvHD prophylaxis is lifesaving for DOCK8 deficiency cases.

Background: Recent findings strongly support hematopoietic stem cell transplantation (HSCT) in patients with severe presentation of LPS-responsive beige-like anchor protein (LRBA) deficiency, but long-term follow-up and survival data beyond previous patient reports or meta-reviews are scarce for those patients who do not receive a transplant. Objective: This international retrospective study was conducted to elucidate the longitudinal clinical course of patients with LRBA deficiency who do and do not receive a transplant. Method: We assessed disease burden and treatment responses with a specially developed immune deficiency and dysregulation activity score, reflecting the sum and severity of organ involvement and infections, days of hospitalization, supportive care requirements, and performance indices. Results: of 76 patients with LRBA deficiency from 29 centers (median follow-up, 10 years; range, 1-52), 24 underwent HSCT from 2005 to 2019. the overall survival rate after HSCT (median follow-up, 20 months) was 70.8% (17 of 24 patients); all deaths were due to nonspecific, early, transplant-related mortality. Currently, 82.7% of patients who did not receive a transplant (43 of 52; age range, 3-69 years) are alive. of 17 HSCT survivors, 7 are in complete remission and 5 are in good partial remission without treatment (together, 12 of 17 [70.6%]). in contrast, only 5 of 43 patients who did not receive a transplant (11.6%) are without immunosuppression. Immune deficiency and dysregulation activity scores were significantly lower in patients who survived HSCT than in those receiving conventional treatment (P = .005) or in patients who received abatacept or sirolimus as compared with other therapies, and in patients with residual LRBA expression. Higher disease burden, longer duration before HSCT, and lung involvement were associated with poor outcome. Conclusion: the lifelong disease activity, implying a need for immunosuppression and risk of malignancy, must be weighed against the risks of HSCT., Styrian Children's Cancer Aid Foundation; Slovenian Research AgencySlovenian Research Agency - Slovenia [P3-0343]; Jonas S_oderquist Foundation; Scientific and Technological Research Council of TurkeyTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [217S847, 318S202]; Deutsche Forschungsgemeinschaft under Germany's Excellence StrategyGerman Research Foundation (DFG) [390939984, 39087428]; E-Rare program of the European Union by the Deutsche ForschungsgemeinschaftGerman Research Foundation (DFG) [GR1617/14-1/iPAD]; Netzwerke Seltener Erkrankungen of the German Ministry of Education and Research [GAIN_ 01GM1910A]; Finnish Foundation for Pediatric Research and Pediatric Research Center, HUS Helsinki University Hospital; Graduate Research Training Scholarship of the Australian government; Hadassah Australia; ERN-RITA network [739543], M.G. Seidel and the Research Unit for Pediatric Hematology and Immunology are supported in part by the Styrian Children's Cancer Aid Foundation. M. Avbeli Stefanija was supported by the Slovenian Research Agency (grant P3-0343). H. Abolhassani was supported by the Jonas S_oderquist Foundation. S. Baris was supported by the Scientific and Technological Research Council of Turkey for the diagnosis of patients with LRBA deficiency (grants 217S847 and 318S202). B. Grimbacher receives support through the Deutsche Forschungsgemeinschaft under Germany's Excellence Strategy (CIBSS-EXC-2189-Project ID 390939984 and RESIST-EXC 2155-Project ID 39087428); through the E-Rare program of the European Union, managed by the Deutsche Forschungsgemeinschaft (grant GR1617/14-1/iPAD); and through the Netzwerke Seltener Erkrankungen of the German Ministry of Education and Research (grant GAIN_ 01GM1910A). M.R.J. Sepp_anen was supported by the Finnish Foundation for Pediatric Research and Pediatric Research Center, HUS Helsinki University Hospital. I. Meyts is a member of the ERN-RITA network (project identification number 739543). B. Shadur is supported by a Graduate Research Training Scholarship of the Australian government and by Hadassah Australia.

Spencer et al. report the first description of human IL-6R deficiency in two patients presenting with recurrent infections, atopy, elevated IgE, and abnormal acute-phase responses., IL-6 excess is central to the pathogenesis of multiple inflammatory conditions and is targeted in clinical practice by immunotherapy that blocks the IL-6 receptor encoded by IL6R. We describe two patients with homozygous mutations in IL6R who presented with recurrent infections, abnormal acute-phase responses, elevated IgE, eczema, and eosinophilia. This study identifies a novel primary immunodeficiency, clarifying the contribution of IL-6 to the phenotype of patients with mutations in IL6ST, STAT3, and ZNF341, genes encoding different components of the IL-6 signaling pathway, and alerts us to the potential toxicity of drugs targeting the IL-6R.

DOCK8 deficiency is a rare inherited combined immunodeficiency, caused by mutations in the DOCK8 gene. We describe a case with DOCK8 deficiency associated with severe CLD in whom orthotopic LT was performed successfully after allogeneic HSCT. A 5 year-old girl with DOCK8 deficiency presented with mild direct hyperbilirubinemia and abnormal GGT level and without a previous history of jaundice. She had severe growth retardation, hepatosplenomegaly and generalized eczema. Progressive worsening of CLD was observed within 4 months. Investigations for etiology of liver disease were negative. Liver biopsy showed bridging necrosis, cholestasis and, cirrhosis. Recurrent immune hemolytic crisis and several viral infections developed in follow-up. She underwent whole cadaveric LT for end-stage liver disease (ESLD) 1 year after allogenic HSCT from a full matched related donor. The postoperative course was uneventful. The patient is alive with normal liver function and moderate skin graft versus host disease for 36 months after LT. In conclusion DOCK8 deficiency can be associated with severe CLD. Successful LT following HSCT is possible in patients with ESLD in DOCK8 deficiency. The timing of LT is challenging in patients requiring both HSCT and LT since conditioning regimens for HSCT can be highly hepatotoxic and the patients with suboptimal liver function can become decompensated during HSCT.

Rare monogenetic diseases serve as natural models to dissect the molecular pathophysiology of the complex disease traits. Rheumatologic disorders by their nature are considered complex diseases with partially genetic origin, as illustrated by their heterogeneous genetic background and variable phenotypic presentation. Recent advances in genetic technologies have helped uncover multiple variants associated with disease susceptibility; however, a precise understanding of genotype-phenotype relationships is still missing. Inborn errors of immunity (IEIs), in addition to recurrent infections, may also present with autoimmune and autoinflammatory rheumatologic manifestations and have provided insights for understanding the underlying the principles of immune system homeostasis and mechanisms of immune dysregulation. This review discusses the rheumatologic manifestations in IEIs with overlapping and differentiating features in immunodeficiencies and rheumatologic disorders.

Mutations in the WAS gene can result in either of the three main phenotypes: classic Wiskott-Aldrich syndrome (WAS), X-linked thrombocytopenia (XLT), and X-linked neutropenia WAS/XLT should be considered in every male presenting with bleeding associated with congenital or early-onset thrombocytopenia and small platelets

Although LRBA deficiency was first categorized as common variable immune deficiency (CVID), with autoimmune manifestations and IBD the phenotype was extended to the spectrum of combined immunodeficiencies

Chronic cough in children may be due to a diverse range of etiologies. We aimed to evaluate children with chronic cough following a standardized cough algorithm and assess obstructive sleep apnea (OSA) as a possible etiology. In addition, cough resolution rates of two different treatment protocols in children with non-specific cough were compared. A total of 237 children referred for chronic cough were assessed and classified according to etiologies. Children with non-specific cough were assigned either in the early-arm (group-1, n = 13) or delayed arm (group-2, n = 23). The presence of OSA was evaluated using a pediatric sleep questionnaire, and polysomnography was handled in indicated patients. Asthma (n = 82) and protracted bacterial bronchitis (PBB) (n = 73) were the most frequent etiologies. Cough resolution was higher in group-1 (100%) compared with group-2 (50%) (absolute risk reduction (rr) = 43.48% [95% CI 21.38-65.58%]). Polysomnography revealed mild (n = 6), moderate (n = 7), or severe (n = 5) OSA in 18 children, with adenoid/adenotonsillary hypertrophy as the leading cause.Conclusion: We recognized asthma and PBB as the most frequent causes of chronic cough in our cohort. Early treatment of patients with high parental anxiety might be beneficial. We also believe that further studies including larger series might eventuate in incorporation of assessment of OSA to standardized algorithms. What is known? • Chronic cough in children may be due to a diverse range of etiologies, including serious respiratory disorders. Thus, its correct diagnosis and treatment are essential. • Although a well-defined reason of chronic cough in adults, obstructive sleep apnea (OSA) has not been been evaluated so far in children with chronic cough. What is new? • We examined OSA for the first time as a possible cause of chronic cough in children and detected OSA with polysomnography in cases who scored high pediatric sleep questionnaire (PSQ) scores. • We believe that studies including larger series might eventuate in incorporation of assessment of OSA to standardized algorithms for children with chronic cough.

Introduction LPS-responsive beige-like anchor protein (LRBA) deficiency is a primary immunodeficiency categorized as common variable immunodeficiency associated with autoimmune manifestations and inflammatory bowel diseases; however, the clinical spectrum has been extended. Here, we present our cohort of Turkish LRBA-deficient patients from a single center, demonstrating a diversity of clinical manifestations. Method Seven affected individuals from five families were assessed retrospectively in this study. Results Of the seven patients with LRBA deficiency, four had homozygous, and two had compound heterozygous mutations. One patient remained disease free until the last follow-up (age 17 years). The most common clinical manifestations of the six symptomatic patients were organomegaly (6/6), autoimmunity (6/6), and chronic diarrhea (5/6). Recurrent infectious episodes were observed in three patients. None of the patients had hypogammaglobulinemia at presentation. B cell subpopulation analysis revealed low numbers of switched-memory B cell numbers in two of the four tested patients. During the disease course, three of the patients died, two of them underwent successful hematopoietic stem cell transplantation (HSCT) from matched sibling donors, and one is under abatacept therapy. Conclusion LRBA defects should always be kept in mind as a differential diagnosis for patients with autoimmune disease affecting multiple organs, chronic diarrhea, and organomegalies. In our experience, early HSCT is a life-saving therapeutic strategy.

Background: The actin-interacting protein WD repeat–containing protein 1 (WDR1) promotes cofilin-dependent actin filament turnover. Biallelic WDR1 mutations have been identified recently in an immunodeficiency/autoinflammatory syndrome with aberrant morphology and function of myeloid cells. Objective: Given the pleiotropic expression of WDR1, here we investigated to what extent it might control the lymphoid arm of the immune system in human subjects. Methods: Histologic and detailed immunologic analyses were performed to elucidate the role of WDR1 in the development and function of B and T lymphocytes. Results: Here we identified novel homozygous and compound heterozygous WDR1 missense mutations in 6 patients belonging to 3 kindreds who presented with respiratory tract infections, skin ulceration, and stomatitis. In addition to defective adhesion and motility of neutrophils and monocytes, WDR1 deficiency was associated with aberrant T-cell activation and B-cell development. T lymphocytes appeared to develop normally in the patients, except for the follicular helper T-cell subset. However, peripheral T cells from the patients accumulated atypical actin structures at the immunologic synapse and displayed reduced calcium flux and mildly impaired proliferation on T-cell receptor stimulation. WDR1 deficiency was associated with even more severe abnormalities of the B-cell compartment, including peripheral B-cell lymphopenia, paucity of B-cell progenitors in the bone marrow, lack of switched memory B cells, reduced clonal diversity, abnormal B-cell spreading, and increased apoptosis on B-cell receptor/Toll-like receptor stimulation. Conclusion: Our study identifies a novel role for WDR1 in adaptive immunity, highlighting WDR1 as a central regulator of actin turnover during formation of the B-cell and T-cell immunologic synapses.

Background: Chronic cough in children is a clinical condition requiring proper intervention. Objectives: This pragmatic real-life study aimed to evaluate children with chronic cough using a standardized clinical algorithm and call attention on obstructive sleep apnea (OSA) as a causative factor. Methods: Children referred for chronic cough between January 2016-January 2017 were assessed and classified according to etiologies. Presence of OSA was evaluated using a pediatric sleep questionnaire (PSQ) and polysomnography was handled in patients with scores ≥8. Results: A total of 251 patients with a median age of 5,88 years (0,28-17,89) were enrolled. The most frequent etiologies were asthma (n=80) (31,8%), protracted bacterial bronchitis (PBB) (n=79) (31,5%) and adenotonsillary hypertrophy (n=19) (7,6%) (Figure 1). We identified 14 patients with OSA (adenotonsillary hypertrophy (n=11), gastroesophageal reflux (n=1), obesity (n=1) and no identifiable cause (n=1)). All patients were cough free after treatment of OSA. Conclusions: As compatible with previous research, we recognized asthma and PBB as the most frequent causes of chronic cough. We believe that implementation of a standardized algorithm including investigation of OSA as an etiological factor of chronic cough in children may improve clinical outcomes. Figure-1: Etiologies of patients (n=251) *: Three patients were diagnosed as astma and gastroesophageal reflux

Introduction HSCT is the curative therapeutic option in PIDs. Due to the increase in survival rates, reduced-toxicity conditioning regimens with treosulfan have become another alternative. The purpose of this retrospective study was to analyze the outcome of treosulfan-based conditioning before HSCT for patients with PID. Method A total of 15 patients that received a treosulfan-based conditioning regimen for HSCT were recruited. Type of diagnosis, donor and stem cell source, pretransplant organ damage, infections, engraftment, chimerism, and transplant-related toxicities were analyzed. Results At a median follow-up time of 32 months, the overall survival was 86.7%. Following HSCT, 14 of 15 patients had engraftment, with 86.7% of the cohort having full-donor chimerism. The most common toxicity was seen on the skin (53.3%). Acute GVHD and chronic GVHD were documented in 53% and 20% of the study population, respectively. Although the cohort consisted of patients with pretransplant liver damage, SOS manifestations were documented in 20%. Conclusion Treosulfan-based conditioning regimens before HSCT are associated with lower toxicity compared to myeloablative regimens, are safe, and have high engraftment rates with full-donor chimerism in patients having PID, regardless of the specified genetic diagnosis and donor type.

Abolhassani et al. show that CD70 deficiency is a novel cause of combined immunodeficiency and EBV-associated diseases, reminiscent of CD27 deficiency. CD70–CD27 interactions play a nonredundant role regulating humoral- and cell-mediated immunity in humans, especially for control of EBV., In this study, we describe four patients from two unrelated families of different ethnicities with a primary immunodeficiency, predominantly manifesting as susceptibility to Epstein-Barr virus (EBV)–related diseases. Three patients presented with EBV-associated Hodgkin’s lymphoma and hypogammaglobulinemia; one also had severe varicella infection. The fourth had viral encephalitis during infancy. Homozygous frameshift or in-frame deletions in CD70 in these patients abolished either CD70 surface expression or binding to its cognate receptor CD27. Blood lymphocyte numbers were normal, but the proportions of memory B cells and EBV-specific effector memory CD8+ T cells were reduced. Furthermore, although T cell proliferation was normal, in vitro–generated EBV-specific cytotoxic T cell activity was reduced because of CD70 deficiency. This reflected impaired activation by, rather than effects during killing of, EBV-transformed B cells. Notably, expression of 2B4 and NKG2D, receptors implicated in controlling EBV infection, on memory CD8+ T cells from CD70-deficient individuals was reduced, consistent with their impaired killing of EBV-infected cells. Thus, autosomal recessive CD70 deficiency is a novel cause of combined immunodeficiency and EBV-associated diseases, reminiscent of inherited CD27 deficiency. Overall, human CD70–CD27 interactions therefore play a nonredundant role in T and B cell–mediated immunity, especially for protection against EBV and humoral immunity.

Biallelic mutations in the genes encoding CD27 or its ligand CD70 underlie inborn errors of immunity (IEIs) characterized predominantly by Epstein-Barr virus (EBV)-associated immune dysregulation, such as chronic viremia, severe infectious mononucleosis, hemophagocytic lymphohistiocytosis (HLH), lymphoproliferation, and malignancy. A comprehensive understanding of the natural history, immune characteristics, and transplant outcomes has remained elusive. Here, in a multi-institutional global collaboration, we collected the clinical information of 49 patients from 29 families (CD27, n = 33; CD70, n = 16), including 24 previously unreported individuals and identified a total of 16 distinct mutations in CD27, and 8 in CD70, respectively. The majority of patients (90%) were EBV+ at diagnosis, but only ∼30% presented with infectious mononucleosis. Lymphoproliferation and lymphoma were the main clinical manifestations (70% and 43%, respectively), and 9 of the CD27-deficient patients developed HLH. Twenty-one patients (43%) developed autoinflammatory features including uveitis, arthritis, and periodic fever. Detailed immunological characterization revealed aberrant generation of memory B and T cells, including a paucity of EBV-specific T cells, and impaired effector function of CD8+ T cells, thereby providing mechanistic insight into cellular defects underpinning the clinical features of disrupted CD27/CD70 signaling. Nineteen patients underwent allogeneic hematopoietic stem cell transplantation (HSCT) prior to adulthood predominantly because of lymphoma, with 95% survival without disease recurrence. Our data highlight the marked predisposition to lymphoma of both CD27- and CD70-deficient patients. The excellent outcome after HSCT supports the timely implementation of this treatment modality particularly in patients presenting with malignant transformation to lymphoma.

Helios, encoded by IKZF2, is a member of the Ikaros family of transcription factors with pivotal roles in T-follicular helper, NK- and T-regulatory cell physiology. Somatic IKZF2 mutations are frequently found in lymphoid malignancies. Although germline mutations in IKZF1 and IKZF3 encoding Ikaros and Aiolos have recently been identified in patients with phenotypically similar immunodeficiency syndromes, the effect of germline mutations in IKZF2 on human hematopoiesis and immunity remains enigmatic. We identified germline IKZF2 mutations (one nonsense (p.R291X)- and 4 distinct missense variants) in six patients with systemic lupus erythematosus, immune thrombocytopenia or EBV-associated hemophagocytic lymphohistiocytosis. Patients exhibited hypogammaglobulinemia, decreased number of T-follicular helper and NK cells. Single-cell RNA sequencing of PBMCs from the patient carrying the R291X variant revealed upregulation of proinflammatory genes associated with T-cell receptor activation and T-cell exhaustion. Functional assays revealed the inability of HeliosR291X to homodimerize and bind target DNA as dimers. Moreover, proteomic analysis by proximity-dependent Biotin Identification revealed aberrant interaction of 3/5 Helios mutants with core components of the NuRD complex conveying HELIOS-mediated epigenetic and transcriptional dysregulation.

International audience; The PI3K-AKT-mTOR signaling axis is a critical molecular pathway in humans, regulating multiple cellular processes. Phosphatidylinositol-3-kinases (PI3K) represent key signaling hubs for signal propagation, driving cell activation, cell polarization and morphological adaptations. Studies on PI3K in human disease have highlighted PI3K-gamma (PI3Kγ) as an appealing drug target for treatment of human disorders.2 Murine PI3Kγ studies showed its importance in regulating innate immune functions and development and activation of T cells, revealing its role in controlling inflammation. However, its role in the human immune system and diseases remains to be investigated.