Increased frequency of circulating CCR5 CD4 T cells in human immunodeficiency virus type 2 infection

CCR5 expression determines susceptibility to infection, cell tropism, and the rate of human immunodefi-ciency virus type 1 (HIV-1) disease progression. CCR5 is also considered the major HIV-2 coreceptor in vivo, in spite of broad coreceptor use in vitro. Here we report a significantly increased proportion of memory-effector CD4 T cells expressing CCR5 in HIV-2-infected patients correlating with CD4 depletion. Moreover, HIV-2 proviral DNA was essentially restricted to memory-effector CD4, suggesting that this is the main target for HIV-2. Similar levels of proviral DNA were found in the two infection categories. Thus, the reduced viremia and slow rate of CD4 decline that characterize HIV-2 infection seem to be unrelated to coreceptor availability. Human immunodeficiency virus type 2 (HIV-2) immunode-ficiency is characterized by slow disease progression with lim-ited impact on the survival of the majority of infected adults (20, 33, 45). The rate of CD4 T-cell decline is much slower in HIV-2 than in HIV-1 disease, and there is a low plasma vira