Macrophage-tropic HIV-1 variants: initiators of infection and AIDS pathogenesis?

The importance of macrophage-tropic HIV-1 variants in AIDS pathogenesis becomes increasingly clear. Macrophage-tropic HIV-1 variants initiate infection, predominate in the asymptomatic phase, and persist throughout infection, even after the emergence of preferential T cell-tropic HIV-1 variants. HIV-1 infection of macrophages may contribute to the overall immune dysfunction observed in AIDS pathogenesis. Here, our knowledge of the biological variability of HIV-1, and specifically macrophage-tropic HIV-1 variants, is reviewed. Moreover, hypotheses about the mechanism of selection for macrophage-tropic variants in transmission, the mechanism by which these variants selectively persist in the asymptomatic phase, and how they may contribute to the general immune dysfunction are presented.