[AUTOIMMUNITY AND IMMUNODEFICIENCIES].

Autoimmune diseases and primary immunodeficiencies share a common pathogenesis characterized by dysregulation of immunity. Although most autoimmune diseases show a polygenic inheritance pattern, it has been shown that monogenic defects of various immune system components could lead to autoimmunity as well. These findings have opened a new pathway for understanding the development of autoimmune diseases and the overlap between immunodeficiency and autoimmunity. Th e mechanism of how a single gene defect leads to autoimmunity is not completely known. The purpose of this clinically-oriented review is to describe the incidence, clinical presentation, and possible mechanisms of autoimmunity in patients with primary immunodeficiencies relevant to rheumatologists.