Systemic lupus erythematosus is a chronic disease that causes inflammation in connective tissues, such as cartilage and the lining of blood vessels, which provide strength and flexibility to structures throughout the body. The signs and symptoms of SLE vary among affected individuals, and can involve many organs and systems, including the skin, joints, kidneys, lungs, central nervous system, and blood-forming (hematopoietic) system. SLE is one of a large group of conditions called autoimmune disorders that occur when the immune system attacks the body’s own tissues and organs. Patients develop autoimmune antibodies that can attach to tissues throughout the body. The joints, lungs, blood, nerves and kidneys are often affected in lupus.