Acquired immunodeficiency syndrome, a syndrome caused by infection with the human immunodeficiency virus (HIV), with ensuing com- promise of the body’s immune system. Features include deficiency of certain types of leukocytes, especially T cells; infection with opportunistic infec- tions that take advantage of the impaired immune response, such as tuberculosis, bacterial pneumo- nia, human herpes virus, or toxoplasmosis; certain types of cancer, particularly Kaposi sarcoma; inabil- ity to maintain body weight (wasting); and in advanced cases, AIDS dementia complex. Treatment for AIDS has advanced rapidly. Antiviral, antibacter- ial, and immune-boosting medications, among other treatments, are part of current treatment protocols.