FIG. 1.

HCV-specific CD4⁺ T-cell proliferative response in peripheral blood mononuclear cells. (A) Time course of proliferative responses in 26 CD4⁺ T-cell responder patients with occult HCV infection, expressed as stimulation indices (SI). Bars represent mean SI of T-cell responses to the HCV protein with standard errors of the means. The horizontal line represents the cutoff for a positive response (SI of >3). (B) Patients with occult HCV infection (black bars) (n = 50) were compared with chronic hepatitis C patients (white bars) (n = 141) for frequencies of virus-specific CD4⁺ T-cell proliferation in response to recombinant HCV core, NS3/helicase, NS4, and NS5A/NS5B proteins.