Abstract: Objective To investigate the diagnostic efficacy of Th9 cells and related cytokine IL-9 in combination with multiple indicators for patients with different degrees of liver fibrosis caused by hepatitis B. Methods Two hundred and seven patients with hepatitis B viral infection were selected. They were divided into non-fibrosis group, mild to moderate fibrosis group and severe fibrosis group according to their pathological examination results. The level of Th9 cells in peripheral blood of each patient was detected by flow cytometry. The level of IL-9 was detected by enzyme linked immunosorbent assay (ELISA). The values of FIB-4 (fibrosis index based on the four factors), APRI (aspartate aminotransferase-to-platelet ratio index), AAR (aspartate aminotransferase/alanine aminotransferase ratio) and RPR (red cell distribution width-to-platelet ratio) were calculated. Spearman correlation analysis was used to explore the correlation between each index and the degree of liver fibrosis. Receiver operating characteristic curves (ROC) were drawn and the diagnostic efficiencies of each and the combination of variables were evaluated. Results There were significant differences in the levels of FIB-4 [4.52(2.48~7.99), 4.71(3.33~6.63), 13.09(6.64~19.43)], APRI [1.29(0.64~2.11), 1.39(0.75~1.87), 2.83(1.23~5.55), AAR [1.29(0.90~1.70), 1.35(0.94~1.83), 1.74(1.34~2.32)], RPR [0.13(0.08~0.23), 0.14(0.11~0.21), 0.28(0.20~0.45)]; IL-9 [24.97±3.615, 34.553±5.708, 43.684±6.534] and Th9 cells [0.28±0.085, 0.464±0.103, 0.626±0.098] among the three groups, respectively (P<0.05). The levels of FIB-4, APRI, AAR, RPR, IL-9 and Th9 cells were positively correlated with the stage of liver fibrosis (r=0.740/0.581/0.379/0.714/0.396/0.421, P<0.01); FIB-4, APRI, AAR, RPR, IL-9 and Th9 have better diagnostic efficacy for mild to moderate fibrostic patients and severe fibrostic patients caused by hepatitis B (AUC:0.878/0.831, 0.772/0.745, 0.614/0.678, 0.862/0.818, 0.685/0.588, 0.633/0.578, respectively). The Combination of various variables can improve the diagnostic efficacies for liver fibrosis caused by hepatitis B (AUC: IL-9+Th9, 0.774/0.668; IL-9+Th9+FIB-4, 0.934/0.862; IL-9+Th9+RPR, 0.929/0.818; IL-9+Th9+FIB-4+RPR, 0.943/0.848). Conclusion FIB-4, APRI, AAR, RPR, IL-9 and Th9 cells have better diagnostic efficacies for liver fibrosis caused by hepatitis B, and the diagnostic efficacies of their combinations are better. They were significantly and positively correlated with the stages of liver fibrosis.

Key words: HBV, Th9, IL-9, Hepatic fibrosis, FIB-4, APRI, AAR, RPR