Still a mystery but 'not likely' a virus.
M F
MF
Goldsmith
D000163:Acquired Immunodeficiency Syndrome / Q000382:microbiology*; D001771:Blood Banks / Q000600:supply & distribution; D015496:CD4-Positive T-Lymphocytes; D006679:HIV Seropositivity; D006801:Humans; D007958:Leukocyte Count; D008297:Male