Associations of plasma IL-22 level with the liver function and infection outcomes in hepatitis C patients

Objective To investigate the associations of plasma interleukin-22 (IL-22) level with liver function, hepatitis C (HCV) RNA load and HCV-related outcomes among HCV infected paid blood donors of Jiangsu Province. Methods A total of 247 subjects were enrolled, including 75 HCV persistent infection cases, 82 HCV natural clearance subjects and 90 healthy controls. The IL-22 level was measured by enzyme linked immunosorbent assay (ELISA). The partial correlation analysis was used to explore the associations of IL-22 level with liver function, HCV RNA load and HCV-related outcomes. Results After controlling for age, sex and body mass index (BMI), the analysis of covariance showed there were significant differences in the level of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) among the three groups (all P<0.05), by contrast, no significant difference in plasma IL-22 level or the outcomes of HCV infection was observed (F=0.911,P=0.676). In addition, a partial correlation analysis showed that the level of IL-22 was positively correlated with the level of ALT, AST and negatively correlated with the level of HCV RNA load. However, the correlation did not show significant differences (all P>0.05). Logistic regression implicated that HCV RNA load was an independent risk factor of ALT level in HCV persistent infection patients (OR=16.926,95% CI:1.695-169.068). Conclusions HCV RNA load was closely related to the liver function in hepatitis C patients. In this study, no significant association was found between plasma IL-22 level and the outcomes of HCV infection. However, large well designed follow-up studies would be needed to further elucidate the impact of IL-22 on liver function and HCV infection outcomes.