Evidence for Kaposi's sarcoma-associated herpes virus infection in patients with idiopathic pulmonary arterial hypertension: a case series and review of the literature

ABSTRACT Background: The pathogenesis of idiopathic pulmonary arterial hypertension (IPAH) is unknown. Recent molecular and immunohistochemical evidence has demonstrated the presence of Kaposi's sarcoma-associated herpes virus (KSHV) at high frequency in lung tissue from patients with IPAH, suggesting a possible role for this virus in the pathogenesis of the disease. Materials and methods: Eighty-seven patients with IPAH (n = 45) or other forms of pulmonary hypertension (n = 42) were prospectively assessed for serologic evidence of KSHV, Epstein–Barr virus (EBV) and human cytomegalovirus (HCMV) infection. Immunofluorescence assays specific for antibodies against latency-associated and lytic antigens of KSHV, as well as commercially available kits that detect antibodies against HCMV and EBV nuclear antigens, were employed. Results: Only one patient with IPAH (2.2%) and one of the patients with other forms of pulmonary hypertension tested seropositive for KSHV. In contrast, 100% and more than 90% of patients with both forms of pulmonary hypertension were positive for EBV and HCMV antibodies, respectively. Conclusions: Italian patients with IPAH do not exhibit serologic evidence of KSHV infection despite a normal ability to mount antibody-mediated responses toward human herpes viruses. KSHV is unlikely to play a role in the pathogenesis of IPAH.