Systemic lupus erythematosus (SLE) is a chronic autoimmune disease that can affect various organs in the body. Common symptoms include fatigue, joint pain, rashes, and kidney problems. It is caused by genetic and environmental factors that lead to abnormal immune responses against the body's own tissues. Diagnosis involves evaluating clinical features along with blood tests to detect autoantibodies. Treatment depends on the specific organs involved but may include medications to suppress the immune system.