Abnormal in vitro proliferation and differentiation of T colony forming cells in AIDS patients and clinically normal male homosexuals.

T cell colonies were generated from the peripheral blood and bone marrow of 11 patients with acquired immune deficiency syndrome (AIDS), 17 normal male and female heterosexuals and seven clinically normal male homosexuals. Mononuclear cells were cultured in methylcellulose both in the absence and presence of interleukin-2 (IL-2) containing conditioned medium. Clinically normal homosexuals showed a low number of T4+ (P less than 0.01) but not T8+ cells. The number of T cell colony forming cells (T-CFC) from both AIDS patients and homosexuals was significantly (P less than 0.01) reduced compared to T-CFC from normal heterosexuals. In seven and four out of 11 AIDS patients, T-CFC from peripheral blood and bone marrow, respectively, were able to generate colonies in the absence of added growth factors and/or mitogenic stimulation. Pooled spontaneous and induced colonies from AIDS patients as well as induced colonies from normal homosexuals were composed of immature cells bearing the T3+, T4+, T6+ T8+ surface phenotype, unlike colonies from normal heterosexuals which displayed mature cells bearing the T3+ T4+ T6- and T3+ T8+ T6- surface phenotype. Moreover, most T-CFC from primary spontaneous and induced colonies had lost their self-renewal capacity either in the absence or the presence of added growth factors. These results suggest that early impairment of T-CFC may play a predominant role in the pathogenesis of AIDS.