Induction of human immunodeficiency virus 1 replication by human herpesvirus 8

Human immunodeficiency virus 1 (HIV-1)-infected individuals are commonly infected with herpesviruses, including cytomegalovirus, herpes simplex virus, varicella-zoster virus, and human herpesvirus 8 (HHV-8, also known as Kaposi sarcoma-associated herpesvirus [KSHV]). Previous studies have demonstrated that coinfection with herpesviruses can modulate HIV-1 replication. This can occur either through direct interaction between the 2 viruses or through secondary effects resulting from the release of cellular factors in response to infection.

To investigate HIV-1 replication in the presence and absence of HHV-8.

HIV-1 replication was analyzed following culture of HIV-1-infected CD4(+) T cells in the presence of HHV-8 infected B-cell lines or control, uninfected B-cell lines. To confirm and extend the results of these in vitro studies, HIV-1-infected T cells were injected into human skin transplanted onto severe combined immunodeficient mice. The human skin was also injected with purified HHV-8 or phosphate-buffered saline as a control and HIV replication measured in biopsy specimens taken 5 to 8 days later.

The results demonstrated a significant increase in HIV-1 replication in the presence of HHV-8 in both the in vitro and in vivo model systems. Although the mechanism responsible for HHV-8 induction of HIV-1 replication remains to be identified, the results indicate that these 2 viruses may interact at the molecular level in coinfected patients, resulting in increased HIV-1 viral load.