Systemic lupus erythematosus and immunodeficiency.

Systemic lupus erythematosus (SLE) is a prototypic systemic autoimmune disease that develops in genetically susceptible individuals in response to environmental factors. SLE and primary immunodeficiency disease (PID) share some clinical manifestations in that certain PIDs present with autoimmune phenomena. Patients with SLE become susceptible to infection via three pathways. First, SLE and PID share some genetic factors, such as complement and mannose-binding lectin genes, which predispose patients to infection. Second, patients with SLE have an inherently high risk of infection because of their intrinsic immunological abnormalities induced by SLE. Third, patients with SLE receiving immunosuppressive treatment are at high risk of infection. Further studies delineating the abnormalities related to both autoimmunity and immunodeficiency would be warranted to identify a new potential drug target for SLE.