Abstract: Objective The aim of this study was to explore the clinical implications of serum interleukin-1 receptor antagonist (IL-1RA), complement C1q tumor necrosis factor related protein 13 (CTRP13) and cytokeratin 18 (CK-18) levels in patients with non-alcoholic fatty liver diseases (NAFLD). Methods 67 patients with NAFLD and 55 healthy individuals at physical examination were enrolled in our hospital between January 2021 and January 2023, and all patients received liver biopsies for hepatic steatosis classification. Serum IL-1RA, CTRP13 and CK-18 levels were detected by ELISA, and the risk factors for severe liver steatosis was determined by multivariate Logistic regression analysis. Results Serum IL-1RA and CTRP13 levels in patients with NAFLD were (328.6±54.3)pg/ml and (2634.2±397.5)pg/ml, both significantly lower than [(673.1±125.4)pg/ml and (3425.7±423.8)pg/ml, P<0.05], while serum CK-18 level was (15.2±3.1)ng/ml, significantly higher than in healthy persons; serum IL-1RA and CTRP13 levels in 17 patients with severe liver steatosis of F3 were (256.3±47.6)pg/ml and (2056.3±308.4) pg/ml, significantly lower than [(388.3±59.4) pg/ml and (3071.5±409.3)pg/ml, P<0.05] in 29 patients with F1 steatosis or in 21 patients with F2 steatosis, while serum CK-18 level was (23.4±4.7)ng/ml, significantly higher than in patients with F1 or in patients with F2 steatosis; the percentages of concomitant obesity, diabetes mellitus, hyperlipidemia, family history of metabolic syndromes, low serum IL-1RA and CTRP13, and high serum CK-18 levels in patients F3 steatosis were 70.6%, 76.5%, 88.2%, 70.6%, 35.3%, 35.3% and 70.6%, significantly different compared to 38.0%, 42.0%, 40.0%, 30.0%, 92.0%, 80.0% and 10.0% in 50 patients with F1/F2 steatosis (P<0.05); the multivariate Logistic regression analysis showed that the obesity , diabetes , hyperlipidemia , low serum IL-1RA and CTRP13 and high serum CK-18 were the risk factors for severe liver steatosis in patients with NAFLD (P<0.05). Conclusion The abnormal changes of serum IL-1RA, CTRP13 and CK-18 levels in patients with NAFLD might help evaluate hepatic steatosis, and warrants further clinical investigation.

Key words: Non-alcoholic fatty liver diseases, Interleukin-1 receptor antagonist, Complement C1q tumor necrosis factor related protein 13, Cytokeratin 18, Implications