CD81 and hepatitis C virus infection: To investigate whether HCV infection is associated with an increase of serum obtained CD81, CD81-p5 was analyzed in a cohort of patients with long term cure of HCV after pegylated interferon-alfa based antiviral therapy and compared with CD81-p5 in healthy controls and in patients with chronic hepatitis C. In patients with cured hepatitis C the CD81-p5 level was similar to healthy controls and significantly lower than in patients with chronic hepatitis C (Figure 2 B).