Human T lymphotropic virus type 1 infection influences hepatitis C virus clearance

To explore the effect of human T lymphotropic virus type 1 (HTLV-1) infecti on on hepatitis C virus (HCV) infection, a survey for these viral infection s was conducted that involved 2280 residents in an area in which HTLV-1 and HCV are endemic. The response of patients with HCV and HTLV-1 to interfero n (IFN)-alpha treatment was also assessed. Antibody to HCV was detected in 13.8% of the residents tested, and antibody to HTLV-1 was detected in 15.4% . The prevalence of HCV RNA was significantly higher among residents who ha d antibodies to both HCV and HTLV-1 than in those who had antibodies to HCV only (P < .05). Sustained elimination of HCV RNA by IFN was significantly more frequent among patients with HCV alone than among those with HCV and H TLV-1. By logistic regression analysis, HTLV-1 infection was associated wit h nonresponse to IFN treatment. Thus, HTLV-1 infection affects the clearanc e, both natural and in association with IFN treatment, of HCV.