Activation in vivo of retroperitoneal fibromatosis-associated herpesvirus,a simian homologue of human herpesvirus-8

Retroperitoneal fibromatosis-associated herpesvirus of rhesus macaques (RFH VMm) is a gamma-herpesvirus closely related to human herpesvirus-8 (HHV-8), which is thought to be a necessary cofactor for the development of Kaposi' s sarcoma (KS) in humans. Here, RFHVMm infection of rhesus macaques exposed to the D-type retrovirus simian retrovirus-2 (SRV-2) is described. Develop ment of SRV-2 viraemia, infection with simian immunodeficiency virus or adm inistration of cyclosporin A could result in persistent RFHVMm viraemia, Fr om this, it is concluded that productive retrovirus infection or otherwise- induced immune suppression has the ability to activate this herpesvirus in vivo, Elevated levels of circulating interleukin-6, a cytokine that plays a central role in KS, were found in RFHVMm-viraemic animals. In viraemic ani mals, RFHVMm was found in tissues that are common sites for the development of AIDS-associated KS, especially the oral cavity, Together, these data su ggest a common biology between RFHVMm infection of macaques and HHV-8 infec tion and pathogenesis in humans.