Autoimmunity in the relatives of patients with immunodeficiency diseases.

Autoimmune disorders are reportedly more frequent than expected in immunodeficient patients and in their relatives. The hypothesis that genetic factors related to immunodeficiency may predispose to the development of autoimmunity was studied in relatives of patients with variable immunodeficiency (VID), ataxia-telangiectasia (A-T), or X-linked infantile agammaglobulinaemia (X-LA). Close relatives of patients with VID or A-T had thyroid and gastric autoantibodies significantly more frequently than did control subjects. No abnormalities were detected in unaffected relatives of X-LA patients. The increased incidence of organ-specific autoantibodies in close relatives of VID patients was confined to those families with more than one member with immunodeficiency. These data suggest that there are at least two forms of VID, one of which is associated with familial autoimmunity. It is postulated that heterozygous carriers of the A-T gene and persons with genes involved in the development of VID may exhibit T-lymphocyte dysfunction which predisposes them to autoimmunity.