Strong interaction between human herpesvirus 6 and peripheral blood monocytes/macrophages during acute infection

Human herpesvirus 6 (HHV-6) encodes a viral chemokine and chemokine receptors that may modify the functions of monocytes/macrophages (MO/Mphi) during productive HHV-6 infection. The interactions between HHV-6 and MO/Mphi during acute infection, however, remain poorly understood. In this study, we investigated the tropism of HHV-6 in peripheral blood mononuclear cells (PBMCs) during acute infection. We detected 637 +/- 273 copies of viral DNA in 10(4) MO/Mphi in contrast, in 10(4) CD4+ T cells, which have been reported to be viral carriers during the acute infection of HHV-6, we found only 115 +/- 42 copies of viral DNA. Consistent with these data, virus was isolated from MO/Mphi an order of magnitude more frequently than from CD4+ T cells. Viral mRNA U79/80, which indicates viral replication, was detectable in the MO/Mphi. In addition, the mRNAs that encode viral chemokine receptors U12 and U51, which may modify the function of MO/Mphi, were expressed in the cells. Therefore, productively infected MO/Mphi may be the dominant cell population that is responsible for HHV-6 viremia during acute HHV-6 infection. The strong interaction of HHV-6 with MO/Mphi may be partly responsible for the pathogenesis of this virus. (C) 2002 Wiley-Liss, Inc.