ACQUIRED IMMUNE DEFICIENCY SYNDROME

the late stage of HIV disease. AIDS involves the loss of function of the immune system as CD4 cells are infected and destroyed, allowing the body to succumb to opportunistic infections (e.g., Pneumocystis carinii pneumonia, toxoplasmosis) that are generally not pathogenic in people with intact immune systems. Common symptoms of AIDS include malignancies and wasting syndrome. The CDC defines AIDS as the presence of at least one of several opportunistic infections or the presence of fewer than 200 CD4 cells/mm3 in an HIV positive individual. (AIDS)