Objective To investigate the changes of Th22 cells,interleukin-22( IL-22),and transcription factor aryl hydrocarbon receptor( AhR) in patients with hepatitis B virus( HBV) infection and their correlation with clinical indices. Methods A total of 11 patients with acute hepatitis B( AHB) and 38 patients with chronic hepatitis B( CHB) who attended Eighth Hospital of Xi'an from March 2018 to March 2019 were enrolled as AHB group and CHB group,respectively,and 16 healthy controls were enrolled as HC group. The patients with CHB received tenofovir disoproxil fumarate( TDF) antiviral therapy. Peripheral blood samples were collected for AHB patients at baseline and 6 months after discharge,and peripheral blood samples were collected for CHB patients at baseline and at months 6 and 12 of treatment;peripheral blood mononuclear cells( PBMCs) and plasma were isolated,then PBMCs were stimulated with phorbol ester + ionomycin or recombinant HBcAg,and flow cytometry was used to measure nonspecific CD3+CD4+IL-22+Th22 cells and HBcAg-specific Th22 cells.ELISA was used to measure the plasma level of IL-22,and quantitative real-time PCR was used to measure the mRNA expression of AhR in PBMCs. The t-test and the paired t-test were used for comparison of normally distributed continuous data between two groups; a one-way analysis of variance was used for comparison of normally distributed continuous data between multiple groups,and the least significant difference t-test was used for further comparison between two groups; the Kruskal-Wallis H test was used for comparison of non-normally distributed continuous data between multiple groups. The chi-square test was used for comparison of categorical data between groups. A Spearman correlation analysis was used to investigate correlation. Results The AHB group had a significantly higher percentage of nonspecific Th22 cells than the CHB group( 2. 86% ± 0. 45% vs 1. 39% ± 0. 33%,t = 11. 80,P < 0. 001) and the HC group( 2. 86% ± 0. 45%vs 0. 80% ± 0. 13%,t = 17. 30,P < 0. 001),and the CHB group also had a significantly higher percentage of nonspecific Th22 cells than the HC group( t = 6. 825,P < 0. 001). The AHB group had a significantly higher percentage of HBc Ag-specific Th22 cells than the CHB group( 2. 97% ± 0. 52% vs 1. 22% ± 0. 22%,t = 16. 58,P < 0. 001). The AHB group had a significantly higher plasma level of IL-22 than the CHB group( 130. 7 ± 39. 97 pg/ml vs 66. 59 ± 20. 83 pg/ml,t = 7. 176,P < 0. 001) and the HC group( 130. 7 ± 39. 97 pg/ml vs50. 63 ± 11. 07 pg/ml,t = 7. 662,P < 0. 001),and the CHB group also had a significantly higher plasma level of IL-22 than the HC group( t = 2. 887,P = 0. 006). The AHB group had significantly higher mRNA expression of AhR than the CHB group( 11. 45 ± 3. 03 vs 4. 81 ±1. 25,t = 10. 85,P < 0. 0001) and the HC group( 11. 45 ± 3. 03 vs 1. 10 ± 0. 17,t = 13. 75,P < 0. 001),and the CHB group also had significantly higher mRNA expression of AhR than the HC group( t = 11. 77,P < 0. 001). In both AHB and CHB patients,the percentage of HBc Ag-specific Th22 cells was positively correlated with alanine aminotransferase( ALT) level( r = 0. 638 and 0. 830,P = 0. 035 and0. 002),and the plasma level of IL-22 was also positively correlated with ALT level( r = 0. 552 and 0. 431,P = 0. 001 and 0. 007). The AHB patients were followed up at 6 months after discharge,and there were significant reductions in the percentage of HBc Ag-specific Th22 cells( 2. 79% ± 0. 56%,t = 3. 055,P = 0. 012) and the plasma level of IL-22( 105. 8 ± 25. 23 pg/ml,t = 2. 362,P = 0. 040) from baseline. All CHB patients received TDF antiviral therapy and were followed up at months 6 and 12 of treatment,and there were significant reductions in the percentage of HBc Ag-specific Th22 cells( t = 4. 353 and 3. 927,all P < 0. 001) and the plasma level of IL-22( t =4. 426 and 4. 810,both P < 0. 0001) from baseline to months 6 and 12 of treatment. Conclusion HBc Ag-specific Th22 cells and IL-22 are closely associated with inflammatory response to HBV infection.