HHV-8 and multiple myeloma.

Recently, a new member of the gamma-herpesvirus family, human herpesvirus 8 (HHV-8), was identified in a case of Kaposi's sarcoma. This virus has also been found in the nonmalignant dendritic cells of the bone marrow from myeloma patients. In addition, HHV-8 is also detectable in the peripheral blood of most patients although its absence suggests earlier stage disease. By contrast, this virus is undetectable in the blood of family members and sexual partners of myeloma patients. Sequencing of HHV-8 open reading frames from myeloma patients show interpatient differences as well as consistent differences in the myeloma samples compared to HHV-8 in other malignancies associated with HHV-8 infection. Consistent expression of both the viral homologues of interferon regulatory factor and IL-8 receptor suggest a possible role for these transforming viral genes in the pathogenesis of myeloma. The latter gene is known to induce angiogenesis and preliminary studies show the abundance of vascular endothelial cells in the bone marrow of myeloma patients.