human herpesvirus 8(redirected from Kaposi's sarcoma-associated herpesvirus)
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human herpesvirus 8 (HHV8),
Among people with AIDS, KS occurs in 15-25% of male homosexuals but only in 1-3% of those who acquire AIDS by nonsexual routes. These facts support the hypothesis that the virus is sexually transmitted. KS is characterized histologically by abnormal vascularization and the presence of proliferating endothelial cells, fibroblasts, infiltrating leukocytes, and spindle-shaped tumor cells. Replication of HHV8 occurs only in a small subset of spindle cells, but most such cells are latently infected. Spindle cell proliferation is apparently triggered by growth factors released from HIV-infected cells. Spindle cells, in turn, produce factors that promote angiogenesis. HHV8 DNA can also be found in circulating CD19 B lymphocytes in 40-50% of AIDS patients with KS. Serologic assays are available for anti-HHV8 antibodies, most of them using viral antigen from cell lines derived from body cavity-based lymphomas. Viral replication is insensitive to acyclovir, but is inhibited by ganciclovir, foscarnet, cidofovir, and interferon alfa.