Protective effect of Th22 cells and intrahepatic IL-22 in drug induced hepatocellular injury

Background & Aims: Th22 cells regulate host immunity against pathogenic invasion, including protecting host against chronic hepatitis B; however, the relationship between drug induced liver injury (DILI) and Th22/Th17 cells is still unclear. We investigated the role of Th22 cells in DILI development. Methods: The frequencies of peripheral Th22/Th17/Th1 cells and intrahepatic IL-22/IL-17 production from DILI, non-DILI liver diseases, and healthy controls were examined. Plasma IL-22/IL-17 and the related cytokines were determined in DILI patients at week 0 (defined as the occurrence of liver injury within 7 days), 4 and 24. Multivariable stepwise logistic regression was applied to explore the associations between various factors and recovery of DILI. Results: The frequencies of Th22/Th17 cells were significantly higher in DILI onset patients than HC. Significant increase of Th22 cells and the related cytokines levels was observed in DILI with hepatocellular injury type. There was a positive correlation between intrahepatic IL-22 level and liver regeneration. Plasma IL-22 level was higher in DILI patients with improved liver function than unimproved function. Multivariable analysis showed that the odds ratio (OR) of plasma IL-22 at 4 weeks was 1.054 [95% confidence interval (CI), 1.012, 1.124]. Conclusions: Increased peripheral and intrahepatic IL-22-secreting cells are detected in DILI. Th22 and its related cytokines might be hepato-protective, which might provide new perspective for understanding the immunopathogenesis of DILI. Plasma IL-22 might be a reliable indicator to evaluate the prognosis of DILI and provide a novel therapeutic target for DILI treatment. (C) 2015 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.