Systemic lupus erythematosus (SLE or lupus) is a chronic autoimmune disease that can be fatal, though with recent medical advances, fatalities are becoming increasingly rare. As with other autoimmune diseases, the immune system attacks the body’s cells and tissue, resulting in inflammation and tissue damage. SLE can affect any part of the body, but most often harms the heart, joints, skin, lungs, blood vessels, liver, kidneys and nervous system. The course of the disease is unpredictable, with periods of illness (called flares) alternating with remission. Lupus can occur at any age, and is most common in women, particularly of non-European descent. Lupus is treatable symptomatically, mainly with corticosteroids and immunosuppressants, though there is currently no cure. Survival in patients with SLE in the United States, Canada, Europe, and China is approximately 95% at 5 years, 90% at 10 years, and 78% at 20 years.