title: Acquired immunodeficiency syndrome cause(s) still elusive.
mesh_terms: D000163:Acquired Immunodeficiency Syndrome / Q000276:immunology*; D006716:Homosexuality; D006801:Humans; D007111:Immunity, Cellular; D007275:Injections, Intravenous / Q000009:adverse effects; D008297:Male; D011010:Pneumocystis / Q000302:isolation & purification; D012514:Sarcoma, Kaposi / Q000209:etiology / Q000276:immunology* / Q000382:microbiology; D019966:Substance-Related Disorders / Q000276:immunology; D014481:United States