Systemic lupus erythematosus (SLE) is a severe, disabling systemic autoimmune disease characterized by the production of autoantibodies. The clinical symptoms and immunologic manifestations of SLE are diverse. African-Americans have a 3 fold increased incidence of SLE, develop SLE at an earlier age, and have increased morbidity and mortality compared with Caucasians. Our central study hypothesis is that there are specific genetic factors that interact with environmental exposures leading to the development of SLE. The African-American Gullah population lives on the Sea Islands of South Carolina and Georgia. They are unique in their genetic homogeneity with minimal Caucasian admixture, making them an ideal cohort to address questions of environmental and genetic influence on development and progression of SLE.