T4+ cell production of interferon gamma and the clinical spectrum of patients at risk for and with acquired immunodeficiency syndrome.

To fully characterize the relationship between the clinical manifestations of human immunodeficiency virus infection and T4+ cell defects, we determined T4+ cell number and interferon gamma (IFN-gamma) production in 238 patients. For asymptomatic homosexuals, patients with acquired immunodeficiency syndrome (AIDS)-related complex (ARC), and patients with fully established AIDS, clinical status correlated linearly with both T4+ cell number and T4+ cell-derived (antigen-stimulated) IFN-gamma secretion. For asymptomatic homosexuals, abnormalities in T4+ cell number and IFN-gamma generation were similar irrespective of human immunodeficiency virus seropositivity. For patients with ARC, those with lymphadenopathy (LA) alone or LA plus zoster or thrombocytopenia displayed T4+ cell defects similar to those observed in asymptomatic homosexuals. Patients with ARC with LA plus constitutional symptoms and/or oral thrush, however, had fewer T4+ cells, were strikingly more deficient in IFN-gamma production, and closely resembled those with AIDS. Among patients with AIDS, certain individuals with Kaposi's sarcoma (KS) alone were sufficiently less cytopenic and less immunodeficient than patients with opportunistic infections (Ols) to suggest that the immune impairment that predisposes to KS may differ. At the time patients with KS developed Ols, however, T4+ cell number and IFN-gamma-generating capacity had declined to the remarkably low levels observed in virtually all patients with Ols alone.