The frequency of liver IL-17+ T cells was significantly higher in both HBV-related liver failure (CLF and ACLF) than in HC (P = 0.0001). The IL-17+/Treg ratio was significantly higher in ACLF and CLF than in HC (7.00, 4.33, and 0.00, respectively). The IL17+ T cells frequency correlated positively with total bilirubin (r = 0.579, P = 0.001) and MELD score (r = 0.367, P = 0.043). This evidence concerns the gene IL17A and liver failure.