Human Herpes Virus8Related Tumors Human Herpes Virus8

With the HIV epidemic in the early 1980s, homosexual men were found to have a 20-fold higher risk than other risk groups in developing Kaposi's sarcoma (KS).The uneven distribution among HIV risk groups lead to the search for an infectious transmissible agent, which eventually led to the discovery of the KS herpes virus or human herpes virus-8 in 1994. HHV-8, a gammaherpesvirus2 (genus Rhadinovirus) is a large (165 kb) double-stranded DNA virus that has an extensive group of regulatory genes obtained from the host genome.142 The DNA sequences of HHV-8 on discovery were found to be homologous to, yet distinct from genes of gamma-herpesvirinae, herpesvirus saimiri, and EBV.143

HHV-8 has been associated in all forms of KS and it is now known to be the etiologic agent of KS.143-146 Aside from KS, HHV-8 has been found in approximately half of the cases of multicentric Castleman's disease (MCD) occurring in non-HIV-infected individuals and nearly in all cases of MCD infected with HIV147 HHV-8 sequences have also been detected in peripheral blood of individuals with MCD, and exacerbation of symptoms has been associated with large increases in HHV-8 viral load.147-149 In addition to KS and MCD, a link between primary effusion lymphoma (PEL) and HHV-8 was first reported in 1995.150

Diseases caused by HHV-8 are greatly dependent on the host's underlying immune status and it has been suggested that most individuals attain a high-risk of developing KS, and other HHV-8-associated diseases such as MCD and PEL with HIV infection.142 For further HHV-8 pathogenesis in KS, MCD, and PEL, refer to each section, respectively.

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