ABSTRACT
<p><b>OBJECTIVE</b>To investigated the relationship between the serum levels of Th1/Th2 cytokines and the progress of viral hepatitis C and the outcome of interferon therapy.</p><p><b>METHODS</b>Serum cytokine detection used the method of ELISA. HCV genotype were classified by direct sequencing. HCV RNA loads were determined by fluorescence quantitative PCR.</p><p><b>RESULTS</b>The levels of IL-2 and TGF-beta in serum of patients with chronic hepatitis C were lower hut IL-5 was higher than those of normal control. The level of IL-6 was positively related to the sera level of ALT and was negatively related to sera HCV RNA load. Patients of HCV genotype 1 had higher sera quantities of IL-6 than those of genotype 2 and patients of genotype 2a had lower sera quantities of IL-2 than those of 2b. The levels of IL-2 had the tendency to decrease whereas IL-6 had the tendency to increase when time went on. The level of TGF-beta increased at early phase but decrease later. There were no difference of all cytokines detected between the groups of response and nonresponse before interferon therapy, hut the quantity of serum IFN-gamma were increased after interferon therapy in the response group.</p><p><b>CONCLUSION</b>The tested cytokines co-participate in the pathogenesis of chronic hepatitis C and have the relationship with the clinical manifestations of the patients. There were no correlation between the levels of Th1/Th2 cytokines in the serum before IFN treatment and the result of IFN therapy. Increasing IFN-gamma in the serum induced by IFN treatment is associated with sustained virological response.</p>