Human T-lymphotropic virus type I uveitis.

In addition to adult T-cell leukemia (ATL) and chronic myelopathy (HAM/TSP), our current study indicates that human T lymphotropic virus type I (HTLV-I) is a causative agent for a specific type of uveitis with unknown etiology (idiopathic uveitis). The present paper describes the seroepidemiological, clinical, and molecular biological evidences that indicate uveitis seen in HTLV-I asymptomatic carriers (HTLV-I uveitis) is a distinct clinical entity. In an HTLV-I endemic area in Japan, the seroprevalence of HTLV-I in idiopathic uveitis was 38%, while those in uveitis with defined etiology and in non-uveitic ocular diseases were 10% and 19%, respectively. Strikingly, the HTLV-I seroprevalence in younger aged patients (20-49 years) with idiopathic uveitis was 49%, while only 8% in the control group (P < 0.001). A very similar observation was recorded even in HTLV-I less endemic area, suggesting that HTLV-I infection plays a role as a risk factor for idiopathic uveitis. Clinical analysis revealed that an intermediate uveitis characterized by moderate opacities in the vitreous body and retinal vasculitis was seen in the majority the patients. The proviral DNA of HTLV-I was detected from inflammatory cells in the eye of all tested patients using PCR technique. These data thus indicate that HTLV-I is closely related to a certain type of uveitis and the uveitis (HTLV-I uveitis) is a distinct clinical entity.