Absence of Kaposi's sarcoma-associated herpesvirus in patients with pulmonary arterial hypertension

Rationale: In addition to Kaposi's sarcoma, Kaposi's sarcoma-associated herpesvirus (KSHV or HHV-8) has been associated with two other diseases: primary effusion lymphoma and the plasma cell variant of multicentric Castleman's disease. Recently, evidence of KSHV infection was reported in plexiform lesions of idiopathic pulmonary arterial hypertension (IPAH) as well as in adjacent parenchyma and bronchial epithelial cells. Objectives: To further investigate a possible association of KSHV and pulmonary arterial hypertension. Methods and Measurements: Twenty-six lungs explanted from German patients suffering from IPAH were tested for the presence of KSHV antigen and genomes by immunohistochemistry (IHC) and polymerase chain reaction (PCR). Main Results: When stained with a commercial monoclonal antibody directed against the latency-associated nuclear antigen of KSHV, LANA-1, a positive signal reminiscent of the "speckled" nuclear pattern typical of latently KSHV-infected cells was found in 16 (61.5%) cases. Alveolar and bronchial epithelial cells in areas of unremarkable lung tissue, but not cells within the plexiform lesions, were the predominantly stained cell types. Different KSHV-PCR assays (based on orf26, orfK6, and orf72) performed on samples that had tested positively in IHC, however, could not confirm KSHV infection, indicating that the IHC signal was not due to KSHV infection. One IHC-negative patient tested positive by PCR. A PCR based on consensus degenerate hybrid oligonucleotide primers (CODE-HOP) to detect yet unknown T-herpesviruses did not reveal any specific sequences. Conclusions: KSHV is unlikely to play a role in the pathogenesis of IPAH.