The Kaposi's sarcoma-associated herpesvirus (human herpesvirus-8) in Kaposi's sarcoma, malignant lymphoma, and other diseases

Background: Two novel nonhuman DNA fragments were discovered in an AIDS-related Kaposi's sarcoma (KS) lesion using representational difference analysis. Design: These sequences belong to a previously unidentified gamma-2-herpesvirus exhibiting homology with Herpesvirus saimiri and Epstein-Barr virus. This virus was named Kaposi's sarcoma-associated herpesvirus (KSHV) and provisionally designated human herpesvirus-8 (HHV-8). Results. KSHV is detectable in more than 90% of classical-Mediterranean, iatrogenic, endemic-African, and AIDS-epidemic KS lesions. In situ PCR studies have demonstrated KSHV in the spindle cells and endothelial cells of KS lesions. KSHV appears to be a transmissible B-lymphotropic herpesvirus. It is detectable in circulating B cells in some HIV-infected patients, and this finding appears to predict the future development of KS among these individuals. KSHV has been identified in a rare and distinct subset of malignant lymphoma referred to as body cavity-based lymphoma but not in other lymphoid neoplasms. KSHV is absent from most other HIV- and non-HIV-associated lymphadenopathies. Conclusions: Further studies should lead to a better understanding of the role of KSHV in the pathogenesis of these disorders and may eventually show that KSHV represents the long sought-after etiologic agent of Kaposi's sarcoma.