In a study of 112 patients with NAFLD (of whom 51 had biopsy-proven NAFL and 30 biopsy-proven NASH) a higher frequency of IFN-γ+ and/or IL-4+ cells was observed in peripheral blood of patients with NAFL and NASH than healthy controls, and a marked increase in intrahepatic IL-17, IL-4, and IFN-γ-producing T cells in NAFLD patients, compared to peripheral blood. This evidence concerns the gene IL17A and metabolic dysfunction-associated steatohepatitis.