Significance of changes in serum IL-18 and IL-1β levels in patients with chronic hepatitis C

AIM:To investigate the roles of serum IL-18 and IL-1β in the progression of chronic hepatitis C and explore the correlation between serum IL-18 and IL-1β levels and the efficacy of interferon (IFN) therapy. METHODS:The levels of IL-18 and IL-1β in the serum of 30 chronic hepatitis C patients were determined before and after they received IFN therapy to observe changes in the serum levels of the two cytokines in different periods after HCV infection. Moreover,the correlations of serum IL-18 and IL-1β levels with ALT level,HCV genotype,IL-2 and IL-6 levels were analyzed. The differences in the serum levels of the two cytokines were also compared between patients with response and nonresponse to interferon treatment. The levels of serum cytokines were determined by ELISA. HCV genotypes were classified by direct sequencing. HCV RNA loads were determined by fluorescence quantitative PCR. RESULTS:The level of IL-18 in the serum of chronic hepatitis C patients was higher than that of healthy controls (1077.44 ± 657.58 ng/L vs 259.92 ± 328.47 ng/L,P < 0.001). No significant difference in the level of serum IL-1β was noted between chronic hepatitis C patients and healthy controls though it had an upward trend over time (in contrast to a downward trend for IL-18). Severe patients had higher serum IL-1β level than mild ones (4.99 ± 1.44 ng/L vs 3.68 ± 0.76 ng/L,P < 0.05). The levels of the two cytokines were not significantly different among patients with different genotypes or subtypes of HCV. The level of IL-18 was positively correlated with that of IL-2 (r = 0.434,P < 0.05) rather than IL-6. The level of IL-1β was not correlated with those of IL-2 and IL-6. No significant differences were noted in the serum levels of IL-18 and IL-1β between patients with response and nonresponse to IFN therapy. CONCLUSION:Serum IL-18 and IL-1β levels may be correlated with the chronicity and severity of hepatitis C but can not be used for prediction of the efficacy of IFN therapy.