Enrollment and randomization of the study subjects. Subjects were enrolled through Wuhan CDC and Zhongnan Hospital, Wuhan University School of Medicine, China. A total of 463 subjects were initially screened for eligibility by a questionnaire survey. A total of 143 subjects were eligible and randomized into 4 groups: 50 control subjects, 50 HCV-infected patients with no heroin use, 20 heroin abusers with no HCV, 23 heroin abusers with HCV infection. 20 subjects were randomly selected from each group for analysis