• viremia;
  • virus carrier;
  • chemokine;
  • chemokine receptor


Human herpesvirus 6 (HHV-6) encodes a viral chemokine and chemokine receptors that may modify the functions of monocytes/macrophages (MO/Mϕ) during productive HHV-6 infection. The interactions between HHV-6 and MO/Mϕ 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 104 MO/Mϕ. in contrast, in 104 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/Mϕ an order of magnitude more frequently than from CD4+ T cells. Viral mRNA U79/80, which indicates viral replication, was detectable in the MO/Mϕ. In addition, the mRNAs that encode viral chemokine receptors U12 and U51, which may modify the function of MO/Mϕ, were expressed in the cells. Therefore, productively infected MO/Mϕ 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/Mϕ may be partly responsible for the pathogenesis of this virus. J. Med Virol. 67:364–369, 2002. © 2002 Wiley-Liss, Inc.