KSHV (HHV8) infection

KSHV (HHV8) is an ancient virus that has most likely co-existed with some human populations since the origins of Homo sapiens. In spite of its co-evolution with humans, it appears to be now rare in many parts of the world and to be largely confined to sub-Saharan Africa and Southern Europe. Like other herpesviruses, it appears to be mainly transmitted during childhood in endemic countries. Among homosexual men KSHV appears to be transmitted during sexual contact. KSHV is associated with three human neoplastic conditions: Kaposi's sarcoma, primary effusion lymphoma and the plasma cell variant of Multicentric Castleman's disease. In most tumour cells the virus persists in a latent form, with minimal expression of viral genes. Among the three KSHV-associated neoplastic disorders, KSHV appears to adopt the least restrictive gene expression pattern in Multicentric Castleman's disease, suggesting that perhaps not just latent viral genes, but also immediate-early or early genes, such as the viral homologues of interleukin 6 or chemokines, may play a role in pathogenesis. Several case reports suggest that KSHV may also be involved in benign lymphoproliferations and perhaps in occasional cases of bone marrow failure.