Abstract: Objective The aim of this study was to investigate serum interleukin-17 (IL-17) levels and the single nucleotide polymorphism (SNP) of its gene at -197A/G locus in patients with alcoholic liver diseases (ALD). Methods 44 patients with alcoholic fatty liver, 40 with alcoholic hepatitis, 34 with alcoholic cirrhosis and 18 with ALD-related liver cancer were recruited in this study between October 2015 and October 2020, and serum IL-17 level was detected by ELISA. The gene polymorphisms at -197A/G locus were detected by single nucleotide test kits. Results Serum IL-17 level in patients with liver cancer was (8.7±1.4) pg/mL, significantly higher than [(3.7±0.3) pg/mL, (4.0±0.6) pg/mL and (6.9±0.8) pg/mL, respectively, P<0.05] in patients with alcoholic fatty liver, alcoholic hepatitis and alcoholic cirrhosis; serum ALT, AST, GGT and ALB levels in patients with liver cancer were (54.3±13.3)U/L,(53.8±13.7)U/L,(262.2±17.9)U/L and (33.9±13.8)g/L, those in patients with alcoholic liver cirrhosis were (39.8±8.8)U/L,(40.1±7.2)U/L, (251.1±7.9)U/L and (31.1±2.6)g/L, in alcoholic hepatitis were (84.0±7.5)U/L,(75.4±6.8)U/L, (245.1±5.6)U/L and (43.1±5.7)g/L, all significantly different compared to(29.5±5.2)U/L,(30.5±7.8)U/L, (142.7±5.2)U/L and (42.7±3.2)g/L, respectively, P<0.05] in patients with alcoholic fatty liver; the distribution frequencies of AA genotype of IL-17 gene at -197A/G locus in patients with liver cancer and alcoholic cirrhosis were 77.9% and 64.7%, significantly higher than 22.7% and 27.5% (P<0.05) in patients with alcoholic fatty liver and alcoholic hepatitis, and the distribution frequencies of A allele in patients with liver cancer and alcoholic cirrhosis were 83.3% and 75.0%, significantly higher than 26.1% and 33.8% (P<0.05) in patients with alcoholic fatty liver and alcoholic hepatitis. Conclusion High serum level of IL-17 might be related with the progression of ALDs and the AA genotype and A allele of IL-17 at -197A/G locus could be the susceptibility genes of patients with ALD, which might increase the risk of alcoholic liver cirrhosis and even liver cancer.

Key words: Alcoholic liver diseases, Interleukin-17, IL-17 gene at -197A/G locus, Gene polymorphism