Systemic lupus erythematosus (SLE) is an autoimmune disease that can severely damage the kidneys, joints, and other tissues. The Carolina Lupus (CLU) Study focuses on measures of endogenous hormone exposure (menstrual and reproductive history), exogenous sources of estrogen (including estrogen replacement therapy and fertility drugs), occupational exposures that have been linked to the development of SLE or other autoimmune diseases (e.g., silica dust), and medical history- related factors including infectious diseases, allergies, and transfusions. The CLU Study is a population-based case-control study of recently diagnosed patients living in eastern North Carolina and South Carolina. Participants include 255 cases and 355 controls frequency matched by age, gender, and state; 90% of the cases are female and 61% are African-American. Cases are identified through 30 community-based rheumatology and 4 university-based rheumatology practices. Population- based controls are identified through drivers license records. Almost half (45%) of the patients have been referred by community-based rheumatologists. Data is collected using a standardized interview and one blood sample. . Serum is collected to measure specific autoantibodies. White blood cells will be stored for additional studies of gene-environment interactions relating to metabolism, immune function, and hormones. Preliminary analysis of medical-related risk factors has been conducted on 159 cases and 201 controls. This analysis was limited to conditions that occurred before the age at diagnosis (or reference age for controls) and were adjusted for age, sex, and race. The risk of developing SLE increased with a history of hives (odds ratio, OR,1.8, 95% CI, 1.0- 3.3) and was somewhat increased with herpes zoster (OR 2.5, 95% CI 0.7-8.5). (None of the subjects were taking immunosuppressant drugs at the time herpes zoster was diagnosed). Also SLE patients were more frequently allergic to sulfa drugs (OR 7.8, 95% CI 2.8-21.6) and to codeine (OR 2.5, 95% CI 0.9 6.8), but not to penicillin (OR 1.1, 95% CI 0.6 -2.1). There was no association between SLE risk and history of eczema, asthma, hay fever, urinary tract infection, or allergy to foods or insect stings. Patients were somewhat more likely than controls to report they had received a transfusion (OR 1.7, 95% CI 0.8-3.5); transfusions relating to anemia or platelet disorders were excluded from this analysis. A history of stroke, blood clot, or pulmonary embolism was also more common in SLE patients (OR 9.9, 95% CI 2.0- 48). These results raise questions about the role of specific inflammatory, infectious, and allergic conditions, and possibly to transfusion-related microchimerism or infections, in the development of SLE. - autoimmune diseases, systemic lupus eryhtematosus, estrogen, menarche, hormone replacement therapy, silica, solvents - Human Subjects & Human Subjects: Interview, Questionaires, or Surveys Only