Abstract: Objective The aim of this study was to investigate the expression of activation markers, such as CD69, CD25, HLA-DR and NKG2D, of peripheral blood invariant natural killer T cells (iNKT), CD4⁺ and CD8⁺ T cells in patients with nonalcoholic fatty liver diseases (NAFLD). Methods 64 patients with NAFLD and 50 healthy persons were enrolled in our hospital between January 2020 and July 2022, and all patients with NAFLD received liver biopsies. The expression of activation markers, such as CD69, CD25, HLA-DR and NKG2D in peripheral blood iNKT, CD4⁺ and CD8⁺ T cells was detected by FCM. Results The liver histopathological examination showed that the nonalcoholic fatty liver (NAFL) was found in 37 cases and nonalcoholic steatohepatitis (NASH) was found in 27 cases; the percentages of peripheral blood CD69⁺iNKT cells in healthy individuals, patients with NAFL and patients with NASH were (10.1±1.7)%,(6.1±1.3)% and (26.7±3.6)%(P<0.05), the percentages of CD25⁺iNKT cells were (83.0±5.9)%, (94.1±8.0)% and (90.8±7.5)%(P<0.05), the percentages of HLA-DR⁺iNKT cells were (15.3±1.7)%, (15.8±2.0)% and (22.3±2.0)%(P>0.05), and the percentages of NKG2D⁺iNKT cells were (44.5±3.5)%, (59.7±4.0)% and (71.3±6.0)%(P<0.05); the percentages of peripheral blood CD69⁺CD4⁺ T cells were (0.7±0.2)%, (0.4±0.1)% and (0.5±0.1)%(P>0.05), the percentages of CD25⁺CD4⁺ T cells were (1.4±0.6)%, (3.0±1.3)% and (1.5±0.7)%(P>0.05), the percentages of HLA-DR⁺CD4⁺ T cells were (2.7±0.7)%, (4.1±1.0)% and (3.9±1.0)%(P<0.05), and the percentages of NKG2D⁺CD4⁺ T cells were (1.6±0.5)%, (0.6±0.2)% and (0.9±0.2)%(P<0.05); the percentages of peripheral blood CD69⁺CD8⁺ T cells in the three groups were (2.0±0.4)%, (1.6±0.3)% and (2.1±0.6)%(P>0.05), the percentages of CD25⁺CD8⁺ T cells were (1.3±0.3)%, (1.1±0.2)% and (1.0±0.2)%(P>0.05), the percentages of HLA-DR⁺CD8⁺ T cells were (5.0±0.7)%, (6.5±1.0)% and (9.6±1.4)%(P<0.05), and the percentages of NKG2D⁺CD8⁺ T cells were (0.6±0.1)%, (0.5±0.1)% and (0.9±0.2)%(P<0.05). Conclusion In this study, we find the immunophenotypic activation differences of peripheral blood iNKT, CD4⁺ and CD8⁺ T cells in patients with NAFL and patients with NASH, and the results show that the percentage of CD69⁺iNK T cells increase in patients with NASH, which might hint the CD69⁺iNK T cells as a biological marker for the diagnosis of patients with NASH.

Key words: Nonalcoholic fatty liver diseases, Nonalcoholic fatty liver, Nonalcoholic steatohepatitis, Invariant natural killer T cells