Regulatory T-cell function in primary humoral immunodeficiency states.

The function of B cells and highly purified T-cell subpopulations was studied in patients with various primary humoral immunodeficiencies. In the presence of normal T4+ cells B cells of the patients with X-linked agammaglobulinemia (XLA) were not capable either for IgM or IgG synthesis, whereas B cells of the patient with hyper-IgM syndrome and three of eight patients with common variable immunodeficiency (CVI) could produce normal amounts of IgM, but not IgG. All patients with XLA and the patient with hyper-IgM syndrome exhibited normal helper function by T4+ cells for both IgG and IgM synthesis of normal B cells. The function of CVI T4+ cells was variable. When the function of the patients' T8+ cells was tested against normal B cells, one CVI patient had overactive suppression capacity; in other patients the suppressor cell activity was normal. The findings indicate considerable heterogenicity in the function of lymphocyte subpopulations of the CVI patients.