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Background Activated phosphatidylinositol-3-OH kinase δ syndrome type 1 (APDS1) is a recently described primary immunodeficiency syndrome characterized by recurrent respiratory tract infections, lymphoid hyperplasia, and Herpesviridae infections caused by germline gain-of-function mutations of PIK3CD. Hematopoietic stem cell transplantation (HSCT) can be considered to ameliorate progressive immunodeficiency and associated malignancy, but appropriate indications, methods, and outcomes of HSCT for APDS1 remain undefined. Objective Our objective was to analyze the clinical manifestations, laboratory findings, prognosis, and treatment of APDS1 and explore appropriate indications and methods of HSCT. Methods We reviewed retrospectively the medical records of cohorts undergoing HSCT at collaborating facilities. Results Thirty-year overall survival was 86.1%, but event-free survival was 39.6%. Life-threatening events, such as severe infections or lymphoproliferation, were frequent in childhood and adolescence and were common indications for HSCT. Nine patients underwent HSCT with fludarabine-based reduced-intensity conditioning. Seven patients survived after frequent adverse complications and engraftment failure. Most symptoms improved after HSCT. Conclusion Patients with APDS1 showed variable clinical manifestations. Life-threatening progressive combined immunodeficiency and massive lymphoproliferation were common indications for HSCT. Fludarabine-based reduced-intensity conditioning–HSCT ameliorated clinical symptoms, but transplantation-related complications were frequent, including graft failure.

Next-generation DNA sequencing has accelerated the genetic characterization of many human primary immunodeficiency diseases (PIDs). These discoveries can be lifesaving for the affected patients and also provide a unique opportunity to study the effect of specific genes on human immune function. In the past 18 months, a number of independent groups have begun to define novel PIDs caused by defects in the caspase recruitment domain family, member 11 (CARD11) –B-cell chronic lymphocytic leukemia/lymphoma 10 (BCL10) –mucosa-associated lymphoid tissue lymphoma translocation gene 1 (MALT1 [CBM]) signalosome complex. The CBM complex forms an essential molecular link between the triggering of cell-surface antigen receptors and nuclear factor κB activation. Germline mutations affecting the CBM complex are now recognized as the cause of novel combined immunodeficiency phenotypes, which all share abnormal nuclear factor κB activation and dysregulated B-cell development as defining features. For this "Current perspectives" article, we have engaged experts in both basic biology and clinical immunology to capture the worldwide experience in recognizing and managing patients with PIDs caused by CBM complex mutations.

Shaping of the secondary antibody repertoire is generated by means of class-switch recombination (CSR), which replaces IgM with other isotypes, and somatic hypermutation (SHM), which allows production of high-affinity antibodies. However, the molecular mechanisms underlying these important processes have long remained obscure. Immunodeficiency with hyper-IgM comprises a group of genetically heterogeneous defects of CSR variably associated with defects of SHM. The study of these patients has allowed us to recognize that both T-cell-B-cell interaction (resulting in CD40-mediated signaling) and intrinsic B-cell mechanisms are involved in CSR and SHM. Elucidation of the molecular defects underlying these disorders has been essential to better understand the molecular basis of Ig diversification and has offered the opportunity to define the clinical spectrum of these diseases and to prompt more accurate diagnostic and therapeutic approaches.

WOS: 000352238600023, PubMed ID: 25312759, Background: Immunoglobulin class-switch recombination defects (CSR-D) are rare primary immunodeficiencies characterized by impaired production of switched immunoglobulin isotypes and normal or elevated IgM levels. They are caused by impaired T:B cooperation or intrinsic B cell defects. However, many immunoglobulin CSR-Ds are still undefined at the molecular level. Objective: This study's objective was to delineate new causes of immunoglobulin CSR-Ds and thus gain further insights into the process of immunoglobulin class-switch recombination (CSR). Methods: Exome sequencing in 2 immunoglobulin CSR-D patients identified variations in the INO80 gene. Functional experiments were performed to assess the function of INO80 on immunoglobulin CSR. Results: We identified recessive, nonsynonymous coding variations in the INO80 gene in 2 patients affected by defective immunoglobulin CSR. Expression of wild-type INO80 in patients' fibroblastic cells corrected their hypersensitivity to high doses of gamma-irradiation. In murine CH12-F3 cells, the INO80 complex accumulates at Sa and Em regions of the IgH locus, and downregulation of INO80 as well as its partners Reptin and Pontin impaired CSR. In addition, Reptin and Pontin were shown to interact with activation-induced cytidine deaminase. Finally, an abnormal separation of sister chromatids was observed upon INO80 downregulation in CH12-F3 cells, pinpointing its role in cohesin activity. Conclusion: INO80 deficiency appears to be associated with defective immunoglobulin CSR. We propose that the INO80 complex modulates cohesin function that may be required during immunoglobulin switch region synapsis., National Institute of Health and Medical ResearchInstitut National de la Sante et de la Recherche Medicale (Inserm); le fonds de recherche clinique du Ministere de la Sante; European Union (EUROPAD) [201549]; European Union (ERC advanced grant PID-IMMUNE) [249816]; Association Contre Le Cancer; Fondation pour la Recherche MedicaleFondation pour la Recherche Medicale [ING20130526624]; la Ligue Contre le Cancer (Comite de Paris); Agence Nationale de la RechercheFrench National Research Agency (ANR) [2010-CSRD]; French Agence Nationale de la Recherche as part of the Investments for the Future programFrench National Research Agency (ANR) [ANR-10-IAHU-01]; La Ligue National contre le Cancer (France); Fondation ARC, France; Institut National du Cancer (INCA), FranceInstitut National du Cancer (INCA) France; German Federal Ministry of Education and ResearchFederal Ministry of Education & Research (BMBF) [BMBF 01 EO 0803]; Canadian Gene Cure Foundation and Finding of Rare Disease Genes (FORGE) Canada; National Institutes of HealthUnited States Department of Health & Human ServicesNational Institutes of Health (NIH) - USA [AI037526], This study was supported by the National Institute of Health and Medical Research, le fonds de recherche clinique du Ministere de la Sante, the European Union's Seventh Research and Technological Development Framework Programme (EUROPAD contract 201549 and ERC advanced grant PID-IMMUNE contract 249816), Association Contre Le Cancer, the Fondation pour la Recherche Medicale (grant number: ING20130526624), la Ligue Contre le Cancer (Comite de Paris) and the Agence Nationale de la Recherche (grant: 2010-CSRD) and a government grant managed by the French Agence Nationale de la Recherche as part of the Investments for the Future program (ANR-10-IAHU-01). This work in the Epigenetics group at the International Agency for Research on Cancer was supported by the La Ligue National contre le Cancer (France), Fondation ARC, France, and Institut National du Cancer (INCA), France. This study was also funded by the German Federal Ministry of Education and Research (grant: BMBF 01 EO 0803) and by the Canadian Gene Cure Foundation and Finding of Rare Disease Genes (FORGE) Canada. This work was supported in part by National Institutes of Health grant AI037526 to M.C.N. M.C.N. is a Howard Hughes Medical Institute investigator. S.K. is a Centre National de la Recherche Scientifique researcher.

International audience; BACKGROUND: We investigated 7 male patients (from 5 different families) presenting with profound lymphopenia, hypogammaglobulinemia, fluctuating monocytopenia and neutropenia, a poor immune response to vaccine antigens, and increased susceptibility to bacterial and varicella zoster virus infections. OBJECTIVE: We sought to characterize the genetic defect involved in a new form of X-linked immunodeficiency. METHODS: We performed genetic analyses and an exhaustive phenotypic and functional characterization of the lymphocyte compartment. RESULTS: We observed hemizygous mutations in the moesin (MSN) gene (located on the X chromosome and coding for MSN) in all 7 patients. Six of the latter had the same missense mutation, which led to an amino acid substitution (R171W) in the MSN four-point-one, ezrin, radixin, moesin domain. The seventh patient had a nonsense mutation leading to a premature stop codon mutation (R533X). The naive T-cell counts were particularly low for age, and most CD8(+) T cells expressed the senescence marker CD57. This phenotype was associated with impaired T-cell proliferation, which was rescued by expression of wild-type MSN. MSN-deficient T cells also displayed poor chemokine receptor expression, increased adhesion molecule expression, and altered migration and adhesion capacities. CONCLUSION: Our observations establish a causal link between an ezrin-radixin-moesin protein mutation and a primary immunodeficiency that could be referred to as X-linked moesin-associated immunodeficiency.

Three new BENTA patients sharing the same novel, autosomal dominant gain-of-function missense mutation in CARD11 (C49Y) provide new insight into the progression of this disorder from childhood to adulthood.

Supported by project and program grants from the National Health and Medical Research Council (NHMRC) of Australia (to E.K.D., S.G.T., C.S.M., D.A.F., and M.C.C.), Cancer Council NSW (to S.G.T. and U.P.), and Rockefeller University Center for 541 Clinical and Translational science (5UL1RR024143, to J.-L.C.). C.S.M. is a recipient of a Career Development Fellowship and S.G.T. is a recipient of a Principal Research Fellowship from the NHMRC of Australia. Disclosure of potential conflict of interest: C. S. Ma has been supported by one or more grants from the National Health and Medical Research Council of Australia (NHMRC). J. Peake has received one or more payments for lecturing on allergy topics and has been reimbursed for travel/accommodations/meeting expenses. M. A. French has received one or more payments for lecturing from or is on the speakers’ bureau for ViiV Australia, MSD Australia, and Janssen Australia and has received one or more payments for travel/accommodations/meeting expenses from MSD Australia and ViiVAustralia. J.-L. Casanova has been supported by one or more grants from the National Institutes of Health (grant no. 8UL1TR000043); has consultancy arrangements with Regeneron, GlaxoSmithKline, NovImmune, BiogenIdec, Merck, and Sanofi- Aventis; and has received one or more grants from or has one or more grants pending with Merck. S. G. Tangye has been supported by one or more grants from the NHMRC of Australia; has received support for travel from ESID, Keystone Symposia, and the Jeffrey Modell Foundation; and has received one or more fees for serving as an expert witness in a patent dispute. E. K. Deenick has been supported by one or more grants from NHMRC, has received one or more payments for travel/accommodations/meeting expenses from the Japanese Society for Immunology, and has received one or more paid honoraria as an Editor for Immunology and Cell Biology. The rest of the authors declare that they have no relevant conflicts of interest.

Background The generation of high-affinity antibodies requires the presence of a population of CD4+ T cells (follicular TH [TFH] cells) in the lymph node follicles. These cells differ from TH1, TH2, and TH17 effector cells in that they strongly express activation markers and the chemokine receptor CXCR5 and secrete large amounts of IL-21 and CXCL13. Small numbers of nonactivated CD4+CD45RO+CXCR5+ T cells are also found in the blood. Objective We sought to obtain in vitro a population close to the TFH cells and to study the presence of this cell population among patients with autosomal dominant hyper-IgE syndrome carrying heterozygous signal transducer and activator of transcription 3 (STAT3) mutations that impair the IL-21 signaling required for B-cell differentiation. Methods CD4+CD45RO+CXCR5+ T cells were isolated from blood and activated by CD3/T-cell receptor. Results We found that CD4+CD45RO+CXCR5+ activated T cells corresponding to circulating bona fide memory TFH cells and that STAT3-deficient patients have abnormally low numbers of "TFH-like" blood T cells. However, STAT3-deficient TFH cells have much the same phenotypic and functional characteristics as TFH cells from healthy control subjects. The ability of STAT3-deficient TFH cells to produce IL-21 on CD28/T-cell receptor activation and to proliferate did not differ from that observed for control TFH cells in vitro. Although the STAT3-deficient TFH cells were also able to help control B cells to produce IgG and IgA, induction of IgG production by naive B cells was impaired. Conclusion Heterozygous mutations in STAT3 lead to reduced numbers of circulating TFH-like cells, a finding that might account (at least in part) for the observed defect in antibody production.