Intracellular cytokine analysis of CD4-positive T cells predictive of sustained response to interferon therapy for patients with chronic hepatitis C

We investigated whether the measurement of serum interleukin 18 (IL-18) and intracellular cytokine analysis of peripheral blood CD4-positive T cells (ICA-CD4(+) Tc) of chronic hepatitis C (CH-C) patients before and two weeks after interferon (IFN) administration are useful for predicting sustained response to IFN. Twenty-nine CH-C patients received IFN every day for two weeks and three times a week for 22 weeks. Patients were divided into two groups: responders, in whom serum HCV-RNA was undetectable at the end of the follow-up (week 48), and nonresponders, in whom any other patterns were seen. Before and two weeks after IFN administration, serum IL-18 ana ICA-CD4(+) Tc as described by Jung et al were measured. Serum IL-18 and the relative prevalence of IFN-gamma(+) and IL-4(+), IFN-gamma(+) and IL-4(-) (Th-1). and IFN-gamma(-) and IL-4(+) cells in the responders were significantly increased, but only the relative prevalence of Th-1 cells in the nonresponders was increased two weeks after IFN therapy. In conclusion, ICA-CD4(+) Tc and the measurement of serum IL-18 might be useful for predicting IFN therapy by comparing the results between before and two weeks after IFN.