Quantitation of human immunodeficiency virus (HIV) with respect to disease stage and zidovudine (AZT) therapy.

Abstract

Quantitation of HIV in 115 seropositive individuals was undertaken to evaluate the potential for HIV transmission as a nosocomial infection through the use of medical devices that may come in contact with the peripheral blood of HIV-infected individuals. The virus burden in the peripheral blood was estimated from the level of: plasma HIV p24 antigenemia; plasma viremia; p24 antigen in peripheral blood mononuclear cell (PBMC) lysates as indicators of productive infection; and frequency of latently infected cells. Negligible HIV levels were observed in the plasma and PBMC lysates of the majority of samples except for late-stage patients with certain opportunistic infections and/or lack of zidovudine (AZT) therapy. Some individuals on AZT therapy and at late-stage of disease may show antigenemia without plasma viremia or alternatively, plasma viremia may be observed without plasma antigenemia. PBMC lysate data indicated that the frequency of productively infected cells was less than one in 20,000 PBMCs for the majority of samples irrespective of status on AZT therapy or disease stage. HIV was detected in greater than 95% of the cocultures and within 14 days for most of the samples, again regardless of the stage of disease or status on AZT therapy. The frequency of latently infected cells in this cohort ranged from 125 to 3125 per million PBMCs and was calculated to be as high as 2.5% of the helpter T-cell (CD4+ cell) population in the peripheral blood. The average latently infected cell frequency was 2-3-fold higher in early stage patients not on AZT than in late-stage patients on AZT therapy.