Quantitative culture of HIV-1 from bronchoalveolar lavage cells

Determination of the infectious virus burden at the organ level is critical for understanding the pathophysiology of human immunodeficiency virus type 1 (HIV-1) infection. To evaluate the burden of HIV-1 in the lung, quantitative cultures were performed on bronchoalveolar lavage (BAL) cells from 11 HIV-1 seropositive subjects without respiratory infections and compared with peripheral blood mononuclear cells (PBMC) obtained from the same subjects. Fifty percent (50%) of subjects had positive BAL cell cultures while 82% had positive PBMC cultures. There was much less virus cultured from BAL cells than from PBMCs, whether using phytohemagglutinin (PHA)-stimulated peripheral blood lymphocyte (PBL) targets (p < 0.05) or adherent monocyte targets (p < 0.02). There was no significant difference between the HIV-1 titers obtained for BAL cells whether using PHA-stimulated PBL or adherent monocyte targets (p = 0.13). These studies demonstrate that BAL cell cultures for HIV-1 in subjects without respiratory infections are less frequently positive than PBMC cultures, that less virus can be recovered from BAL cells than from PBMC, and that HIV-1 isolates from BAL cells replicate in both PHA-stimulated PBL targets and adherent monocyte targets. Quantitative assessment of virus burden in the lung is important for future studies of HIV-1 pathogenesis and for evaluating potential antiretroviral therapies aimed at altering the natural history of organ dysfunction associated with retroviral replication.