Clinical, molecular, and T cell subset analyses in a small cohort of Chinese patients with hyper-IgM syndrome type 1.

Type 1 hyper-IgM syndrome (HIGM1) is a rare primary immunodeficiency disease caused by mutations in the CD40L gene. Patients often present with recurrent infections and autoimmune manifestations. We investigated the clinical and molecular characteristics of HIGM1 in thirteen patients from the Chinese mainland and examined the proportion of CD4(+)CD25(+)FoxP3(+)Treg, Th17, and Th1 cells in the peripheral blood. We identified ten distinct CD40L mutations in eleven patients: one missense mutation, one nonsense mutation, one insertion mutation (in frame), and seven deletions. Six of these mutations were novel. We observed the percentage of Tregs in the peripheral blood of HIGM1 patients decreased markedly compared with that in healthy controls, but no statistically significant differences was found in the percentages of Th17 and Th1. The identified mutations reflect the heterogeneity of the CD40L gene in HIGM1. Precise genetic diagnosis of HIGM1 will enable appropriate therapeutic interventions, reliable detection of carriers, and genetic counseling. Skewed Treg, Th17/Treg, and Th1/Treg profiles may be associated with immune responses to autoimmunity or infection, which requires replication in larger studies.