The European Common Variable Immunodeficiency Disorders registry was started in 1996 to define distinct clinical phenotypes and determine overlap within individual patients. A total of 7 centers contributed patient data, resulting in the largest cohort yet reported. Patients (334), validated for the diagnosis, were followed for an average of 25.6 years (9461 patientyears). Data were used to define 5 distinct clinical phenotypes: no complications, autoimmunity, polyclonal lymphocytic infiltration, enteropathy, and lymphoid malignancy. A total of 83% of patients had only one of these phenotypes. Analysis of mortality showed a considerable reduction in the last 15 years and that different phenotypes were associated with different survival times. Types of complications and clinical phenotypes varied significantly between countries, indicating the need for large, international registries. Ages at onset of symptoms and diagnosis were shown to have a Gaussian distribution, but were not useful predictors of phenotype. The only clinical predictor was polyclonal lymphocytic infiltration, which was associated with a 5-fold increased risk of lymphoid malignancy. There was widespread variation in the levels of serum immunoglobulin isotypes as well as in the percentages and absolute numbers of B cells, confirming the heterogeneity of these conditions. Higher serum IgM and lower circulating CD8 proportions were found to be predictive markers for polyclonal lymphocytic infiltration and autoimmunity, respectively. (Blood. 2008;112:277-286)

X-linked lymphoproliferative syndrome (XLP or Duncan disease) is characterized by extreme sensitivity to Epstein-Barr virus (EBV), resulting in a complex phenotype manifested by severe or fatal infectious mononucleosis, acquired hypogammaglobulinemia and malignant lymphoma. We have identified a gene, SH2D1A, that is mutated in XLP patients and encodes a novel protein composed of a single SH2 domain. SH2D1A is expressed in many tissues involved in the immune system. The identification of SH2D1A will allow the determination of its mechanism of action as a possible regulator of the EBV-induced immune response.

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Lipopolysaccharide (LPS), a product of Gram-negative bacteria, is potent mediator of tumor necrosis factor (TNF)α production by myeloid/macrophage cells. Inhibitors capable of blocking the signaling events that result in TNFα production could provide useful therapeutics for treating septic shock and other inflammatory diseases. Broad spectrum tyrosine inhibitors are known to inhibit TNFα production, however, no particular family of tyrosine kinases has been shown to be essential for this process. Here we show that the Bruton's tyrosine kinase (Btk)-deficient mononuclear cells from X-linked agammaglobulinemia patients have impaired LPS-induced TNFα production and that LPS rapidly induces Btk kinase activity in normal monocytes. In addition, adenoviral overexpression of Btk in normal human monocytes enhanced TNFα production. We examined the role of Btk in TNFα production using luciferase reporter adenoviral constructs and have established that overexpression of Btk results in the stabilization of TNFα mRNA via the 3′ untranslated region. Stimulation with LPS also induced the activation of related tyrosine kinase, Tec, suggesting that the Tec family kinases are important components for LPS-induced TNFα production. This study provides the first clear evidence that tyrosine kinases of the Tec family, in particular Btk, are key elements of LPS-induced TNFα production and consequently may provide valuable therapeutic targets for intervention in inflammatory conditions.

Bruton’s tyrosine kinase (Btk), the gene mutated in the human immunodeficiency X-linked agammaglobulinemia, is activated by LPS and is required for LPS-induced TNF production. In this study, we have investigated the role of Btk both in signaling via another TLR (TLR2) and in the production of other proinflammatory cytokines such as IL-1β, IL-6, and IL-8. Our data show that in X-linked agammaglobulinemia PBMCs, stimulation with TLR4 (LPS) or TLR2 (N-palmitoyl-S-[2, 3-bis(palmitoyloxy)-(2R)-propyl]-(R)-cysteine) ligands produces significantly less TNF and IL-1β than in normal controls. In contrast, a lack of Btk has no impact on the production of IL-6, IL-8, or the anti-inflammatory cytokine, IL-10. Our previous data suggested that Btk lies within a p38-dependent pathway that stabilizes TNF mRNA. Accordingly, TaqMan quantitative PCR analysis of actinomycin D time courses presented in this work shows that overexpression of Btk is able to stabilize TNF, but not IL-6 mRNA. Furthermore, using the p38 inhibitor SB203580, we show that the TLR4-induced production of TNF, but not IL-6, requires the activity of p38 MAPK. These data provide evidence for a common requirement for Btk in TLR2- and TLR4-mediated induction of two important proinflammatory cytokines, TNF and IL-1β, and reveal important differences in the TLR-mediated signals required for the production of IL-6, IL-8, and IL-10.

The thymus in adults infected with the HIV-1 is generally thought to be inactive, both because of age-related involution and viral destruction. We have revisited the question of thymic function in adults, using chest-computed tomography (CT) to measure thymic tissue in HIV-1-seropositive ( n ϭ 99) or HIV-1-seronegative ( n ϭ 32) subjects, and correlating these results with the level of circulating CD4 ϩ and CD8 ϩ T cells that are phenotypically described as naive thymic emigrants. Abundant thymic tissue was detectable in many (47/99) HIV-1-seropositive adults, aged 20-59. Independent of age, radiographic demonstration of thymic tissue was significantly associated with both a higher CD4 ϩ T cell count ( P ϭ 0.02) and a higher percentage and absolute number of circulating naive (CD45RA ϩ CD62L ϩ ) CD4 ϩ T cells ( P Ͻ 0.04). The prevalence of an abundant thymus was especially high in younger HIV-1-seropositive adults ( Յ 39 yr) with CD4 counts in the range 300-500 cells/ l and in older subjects ( Ͼ 40 yr) regardless of CD4 count ( P ϭ 0.03). These studies suggest that the thymus is functional in some but not all adults with HIV-1 disease. ( J. Clin. Invest. 1998.

Common variable immunodeficiency (CVID) is characterized by hypogammaglobulinemia and defects in T-cell functions that could be primary or secondary. We addressed whether CVID is associated with impairment in the dendritic cell

SummaryWe present three common variable immunodeficiency (CVID) patients with severe inflammatory bowel disease of unknown aetiology, resistant to steroid treatment, treated with infliximab. After exclusion of any infection, infliximab was given at a dose of 5 mg/kg every 4 weeks for a 3 month induction followed by every 4-8 weeks depending on clinical response. Two of these patients had predominantly small bowel disease; they both showed clinical response to infliximab with weight gain and improvement of quality of life scores. The third patient had large bowel involvement with profuse watery diarrhea; this patient improved dramatically within 48 hours of having infliximab treatment. All three patients have been maintained on infliximab treatment for between 5 and 53 months (mean 37 months) with no evidence of increased susceptibility to infections in the patients with small bowel disease, although the third patient developed two urinary tract infections and a herpes zoster infection following therapy. This is the first small case series to show that infliximab is a useful addition to current therapy in this rare group of patients with potentially life threatening enteritis.