Immunologic alterations in common variable immunodeficiency

Common variable immunodeficiency (IDCV) is the largest group of symptomatic primary immune deficiencies; it is characterized by hypogammaglobulinemia, poor response to vaccines and increased susceptibility to infections. Cellular phenotypes and abnormalities have been described both in adaptive and innate immune response. Several classifications of common variable immunodeficiency are based on defects found on T and B cells, which have been correlated with clinical manifestations. In recent years, significant progress has been made in elucidating the genetic mechanisms that result in a IDCV phenotype. Massive sequencing technologies have favored the description of mutations in several genes, but only in 2 % to 10 % of patients. These monogenetic defects are: ICOS, TNFRSF13B (TACI), TNFRS13C (BAFFR), TNRFSF12 (TWEAK), CD19, CD81, CR2 (CD21), MS4A1 (CD20), TNFRSF7 (CD27), LRBA, CTLA4, PRKCD, PLCG2, NFKB1, NFKB2, PIK3CD, PIK3R, VAV1, RAC1, BLK, IKZF1 (IKAROS) and IRF2BP2.These findings have provided a possible explanation for the pathogenesis of IDCV, since these molecules play an important role in the co-operation between B and T cells in the germinal center, as well as in intrinsic signaling pathways of both

Immunodeficiency, autoimmunity, and increased risk of B cell malignancy in humans with TRAF3 mutations.

Tumor necrosis factor receptor-associated factor 3 (TRAF3) is a central regulator of immunity. TRAF3 is often somatically mutated in B cell malignancies, but its role in human immunity is not defined. Here, in five unrelated families, we describe an immune dysregulation syndrome of recurrent bacterial infections, autoimmunity, systemic inflammation, B cell lymphoproliferation, and hypergammaglobulinemia. Affected individuals each had monoallelic mutations in TRAF3 that reduced TRAF3 expression. Immunophenotyping showed that patients' B cells were dysregulated, exhibiting increased nuclear factor-κB 2 activation, elevated mitochondrial respiration, and heightened inflammatory responses. Patients had mild CD4+ T cell lymphopenia, with a reduced proportion of naïve T cells but increased regulatory T cells and circulating T follicular helper cells. Guided by this clinical phenotype, targeted analyses demonstrated that common genetic variants, which also reduce TRAF3 expression, are associated with an increased risk of B cell malignancies, systemic lupus erythematosus, higher immunoglobulin levels, and bacterial infections in the wider population. Reduced TRAF3 conveys disease risks by driving B cell hyperactivity via intrinsic activation of multiple intracellular proinflammatory pathways and increased mitochondrial respiration, with a likely contribution from dysregulated T cell help. Thus, we define monogenic TRAF3 haploinsufficiency syndrome and demonstrate how common TRAF3 variants affect a range of human diseases

First Report of the Hyper-IgM Syndrome Registry of the Latin American Society for Immunodeficiencies: Novel Mutations, Unique Infections, and Outcomes

Hyper-IgM (HIGM) syndrome is a heterogeneous group of disorders characterized by normal or elevated serum IgM levels associated with absent or decreased IgG, IgA and IgE. Here we summarize data from the HIGM syndrome Registry of the Latin American Society for Immunodeficiencies (LASID). of the 58 patients from 51 families reported to the registry with the clinical phenotype of HIGM syndrome, molecular defects were identified in 37 patients thus far. We retrospectively analyzed the clinical, immunological and molecular data from these 37 patients. CD40 ligand (CD40L) deficiency was found in 35 patients from 25 families and activation-induced cytidine deaminase (AID) deficiency in 2 unrelated patients. Five previously unreported mutations were identified in the CD40L gene (CD40LG). Respiratory tract infections, mainly pneumonia, were the most frequent clinical manifestation. Previously undescribed fungal and opportunistic infections were observed in CD40L-deficient patients but not in the two patients with AID deficiency. These include the first cases of pneumonia caused by Mycoplasma pneumoniae, Serratia marcescens or Aspergillus sp. and diarrhea caused by Microsporidium sp. or Isospora belli. Except for four CD40L-deficient patients who died from complications of presumptive central nervous system infections or sepsis, all patients reported in this study are alive. Four CD40L-deficient patients underwent successful bone marrow transplantation. This report characterizes the clinical and genetic spectrum of HIGM syndrome in Latin America and expands the understanding of the genotype and phenotype of this syndrome in tropical areas.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Jeffrey Modell FoundationLatin American Advisory Board on Primary Immunodeficiencies initiativeUniv São Paulo, Inst Biomed Sci, Dept Immunol, BR-05508000 São Paulo, BrazilCtr Invest & Estudios, Dept Biomed Mol, Mexico City, DF, MexicoDr Ricardo Gutierrez Childrens Hosp, Buenos Aires, DF, ArgentinaHosp Nacl Ninos Dr Carlos Saenz Herrera, San Jose, Costa RicaPediat Allergy & Immunol Clin, Caxias Do Sul, RS, BrazilAlbert Sabin Hosp, Fortaleza, Ceara, BrazilHosp Base Dist Fed, Brasilia, DF, BrazilIntegrated Ctr Pediat Specialties, Curitiba, PR, BrazilHosp Ninos VJ Vilela, Rosario, ArgentinaHosp Ninos Luis Calvo Mackenna, Santiago, ChileUniv Fed Parana, Dept Pediat, BR-80060000 Curitiba, Parana, BrazilUniv Estadual Campinas, Sch Med, Dept Pediat, Campinas, SP, BrazilConceicao Childrens Hosp, Dept Pediat, Div Allergy & Immunol, Porto Alegre, RS, BrazilChildrens Hosp Lucidio Portela, Teresina, PI, BrazilPontificia Univ Catolica Chile, Div Pediat, Santiago, ChileUniv Estadual Campinas, Sch Med, Dept Med, Campinas, SP, BrazilUniv São Paulo, Ribeirao Preto Med Sch, BR-14049 Ribeirao Preto, SP, BrazilHosp Nacl Edgardo Rebagliati Martins Alergia & In, Lima, PeruUniv Fed Rio de Janeiro, Sch Med, Dept Pediat, Rio de Janeiro, BrazilInst Nacl Pediat, Unidad Invest Inmunodeficiencias, Mexico City, DF, MexicoIMSS, Unidad Med Alta Especialidad 25, Monterrey, Nuevo Leon, MexicoClin Montefiori, Unidad Inmunol, Lima, PeruUNAL, Univ Hosp, Monterrey, Nuevo Leon, MexicoFac Med ABC, Santo Andre, SP, BrazilChildrens Hosp, Dept Pediat, New Orleans, LA USAHop Necker Enfants Malad, INSERM, Unite U768, Paris, FranceUniv Washington, Sch Med, Dept Pediat, Seattle, WA 98195 USASeattle Childrens Res Inst, Seattle, WA USAUniversidade Federal de São Paulo, Dept Pediat, Div Allergy Immunol & Rheumatol, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Pediat, Div Allergy Immunol & Rheumatol, São Paulo, BrazilFAPESP: 2012/50515-4FAPESP: 2006/57643-7FAPESP: 2012/51745-3Web of Scienc