Human herpesvirus 8

Human herpesvirus 8 (HHV-8, KSHV) was discovered in 1994. This first description was made through differential gene amplification technique applied to Kaposi's sarcoma lesions and normal skin obtained from the same individual. HHV-8 is closely related to herpesvirus saimiri and Epstein-Barr virus? both of the Gammaherpesvirinae sub-family. The isolation of HHV-8 in primary cell cultures is difficult. The virus was morphologically observed in and obtained from chronically infected cell lines derived from primary effusion lymphomas. Preliminary serological studies were performed by immunofluorescence and immunoblot assays using these chronically infected cells. Recently, recombinant antigens have also been used with good results. According to the first serological studies, HHV-8 infection seems to be restricted to Kaposi's sarcoma patients or subjects at risk for this disease in Western countries. HHV-8 is probably sexually transmitted. In some African countries, HHV-8 infection seems to be widespread and is also detected in children, which would suggest other ways of transmission. Other means of HHV-8 detection are polymerase chain reaction (PCR) and molecular hybridization. The detection of HHV-8 in human tissues is strongly associated with three diseases: Kaposi's sarcoma, body-cavity-based lymphomas (also designated as primary effusion lymphomas), and Castleman's disease. The virus is present in tissue lesions and also, less frequently and at a lower level, in healthy tissue. HHV-8 may be a causative agent in these three diseases, particularly in Kaposi's sarcoma.