Low T Cell Responses to Human Herpesvirus 8 in Patients with AIDS-Related and Classic Kaposi Sarcoma

BackgroundKaposi sarcoma (KS) occurs mainly in immunocompromised patients and is strongly associated with infection with human herpesvirus 8 (HHV-8; also known as “KS-associated herpesvirus”). We hypothesized that KS is linked to deficiencies in specific anti–HHV-8 T cell immunity MethodsWe studied asymptomatic HHV-8 carriers coinfected with human immunodeficiency virus (HIV; n=23) and patients with HIV-related or classic KS (n=29). We used an interferon–γ enzyme-linked immunospot assay with 56 specific peptides distributed on 6 HHV-8 proteins (glycoprotein [gp] B, gpH, gp35/37, latent nuclear antigen 1 [LANA-1], K12, and K15) to detect HHV-8–specific T cell responses ResultsWe found that patients with KS responded to these peptides less often and had much lower HHV-8–specific T cells counts than did asymptomatic HHV-8 carriers (P=.001 and P=.0004, respectively), regardless of CD4 T cell count or HHV-8 load. The frequency of Epstein-Barr virus–specific T cells was similar in both groups ConclusionsOur results suggest that HIV-related and classic KS are associated with a lack of HHV-8–specific T cells. Also, we have described 8 new HHV-8 T cell epitopes in LANA-1, K12, and K15, including 2 CD4 T cell epitopes. These data provide new insight into HHV-8 cellular immunity