MSH: An acquired defect of cellular immunity associated with infection by the human immunodeficiency virus (HIV), a CD4-positive T-lymphocyte count under 200 cells/microliter or less than 14% of total lymphocytes, and increased susceptibility to opportunistic infections and malignant neoplasms. Clinical manifestations also include emaciation (wasting) and dementia. These elements reflect criteria for AIDS as defined by the CDC in 1993.,CSP: one or more indicator diseases, depending on laboratory evidence of HIV infection (CDC); late phase of HIV infection characterized by marked suppression of immune function resulting in opportunistic infections, neoplasms, and other systemic symptoms (NIAID).,NCI: A disease caused by human immunodeficiency virus (HIV). People with acquired immunodeficiency syndrome are at an increased risk for developing certain cancers and for infections that usually occur only in individuals with a weak immune system.,NCI: A syndrome resulting from the acquired deficiency of cellular immu