HIV-1 in peripheral blood monocytes: An underrated viral source

Abstract

In summary, given the fact that monocytes may circulate in peripheral blood for only 1-3 days before differentiating into macrophages in tissues, our finding of persistent HIV-1 in blood monocytes itself suggests ongoing renewal of infected monocytes by virus replication and/or recent infection in monocytes or their precursor cells. Our findings of more evident HIV-1 replication in CD14+ monocytes suggest that the HIV-1 pool in monocytes could be renewed, as a result of viral replication, more frequently in CD14+ monocytes than in resting CD4+ T cells. Therefore, although the long half-life of HIV-infected CD14+ monocytes appears to be similar to that of resting CD4+ T cells, HIV-1 could turn over at a higher rate in CD14+ monocytes than in resting CD4+ T cells in the presence of HAART. However, the viral pool in CD14+ monocytes could also be renewed by viruses produced from resting and activated CD4+ T cells, and tissue macrophages. The source of HIV-1 in blood monocytes and the contribution they make to the overall pool of HIV-1 replication require more extensive studies. The establishment of HIV-1 infection in CD14+ monocytes in the early stage of infection and ongoing viral replication in CD14+ monocytes present a major challenge to HIV-1 eradication with current regiments of HAART. New therapies with greater potency against viral production in blood monocytes may enhance the efficacy of antiretroviral therapy.