Interactions between beta-herpesviruses and human immunodeficiency virus in vivo: Evidence for increased human immunodeficiency viral load in the presence of human herpesvirus 6

In vitro, beta-herpesviruses can stimulate or inhibit HIV replication under particular circumstances. In order to investigate the effects of beta-herp esvirus infection on HIV replication and vice versa at an organ level, we d etermined the quantitative relationships between cytomegalovirus (CMV), hum an herpesviruses (HHV) 6 and 7, and HIV-1 proviral DIVA using quantitative competitive PCR methods in 141 organs collected at autopsy from 11 AIDS pat ients. The presence of HHV-6 DNA in an organ was significantly associated w ith elevated HIV-1 proviral DNA (difference in HIV median loads, 1.3 log(10 ) genomes; P = 0.004). Consistent with this, there was a trend for the pres ence of HIV-1 proviral DNA to be associated with an elevated HHV-6 load (0. 44 log(10) difference; P = 0.07). In contrast, there were no significant di fferences between viral loads in the combinations of either CMV or HHV-7 wi th HIV-1 proviral DNA load. Pairwise combinations of the beta-herpesviruses revealed that the quantity of HHV-7 was increased in the presence of HHV-6 (difference in median loads, 1.3 log(10); P = 0.001) and the quantity of H HV-6 was increased in the presence of HHV-7 (difference in median loads, 0. 7 log(10); P = 0.002). These results demonstrate that the presence of HHV-6 in an organ is significantly associated with an elevated HIV-1 proviral lo ad and have implications for understanding HIV pathogenesis in the human ho st and the role that P-herpesviruses, especially HHV-6, might play as cofac tors in the HIV disease process. J. Med. Virol. 57:278-282, 1999. (C) 1999 Wiley-Liss, Inc.