To determine the direct influence of ribavirin on differentially polarized CD4+ T cells from chronic hepatitis C, we stimulated our Treg, TH1 and TH2 clones with anti-CD3/anti-CD28 in the presence of variable concentrations of ribavirin and measured their proliferation (figure 2) and cytokine responses (figure 3). The gene discussed is CD28; the disease is chronic hepatitis C virus infection.