Abstract: Objective To investigate serum 25-（OH）D₃ and interleukin-17（IL-17） levels in obese children with nonalcoholic fatty liver disease（NAFLD）.Methods Sixty-two obese children were enrolled in this study between January 2014 and December 2017,and out of them,36 cases were diagnosed as nonalcoholic fatty liver （NAFL） and 26 were nonalcoholic steatohepatitis （NASH）. Thirty healthy children were selected as control. Serum IL-17 and 25-（OH）D₃ levels were assayed by ELISA.Results Serum 25-（OH）D₃ level in children with NAFL was（15.2±2.1） ng/mL,and in children with NASH was （9.6±1.3） ng/ml,both significantly lower than （26.3±2.3） ng/mL in healthy children,while serum IL-17 levels were（17.1±7.8） μg/L and （36.2±12.6） μg/L,both significantly higher than（1.4±0.5） μg/L in healthy children（P<0.05）;serum ALT and AST levels in children with moderate NAFLD were （54.1±15.4） U/L and （46.5±12.6） U/L,and were （117.1±37.1） U/L and （78.5±31.0） U/L in children with severe NAFLD,all significantly higher than （33.4±4.6） U/L and （30.5±2.9） U/L in kids with mild NAFLD（P<0.05）;serum 25-（OH）D₃ level in children with moderate NAFLD was（10.2±1.4） ng/ml and in children with severe NAFLD was（8.4±1.1） ng/ml,both significantly lower than （15.8±2.0） ng/ml in children with mild NAFLD（P<0.05）,while serum IL-7 levels were（22.2±6.3）μg/L and （39.6±9.2） μg/L,respectively,significantly higher than （13.5±3.5） μg/L in children with mild NAFLD （P<0.05）. Conclusion Serum 25-（OH）D₃ levels decrease and serum IL-17 levels increase in obese children with NAFLD,which might be new indicators for supervision of disease progress.

Key words: Nonalcoholic fatty liver disease, NAFLD. 25-（OH）D₃, IL-17, Obese children