[Application of TIGIT combined with interleukin-6 detection in the evaluation of Crohn's disease status]

To explore the application of IL-6, PCT, T lymphocyte subsets and TIGIT expression on T lymphocytes in the evaluation of Crohn's disease status. Using a cross-sectional study, total of 119 confirmed patients with Crohn's disease who were treated in the Affiliated Hospital of Jiangxi University of Traditional Chinese Medicine from June 2020 to December 2022 were selected. The age range was 18-59 years old, and the median age (interquartile range) was 37 (29, 45) years old, including 57 cases in active disease group (30 males, 27 females), 62 cases in disease remission group (33 males, 29 females); 50 healthy control groups (27 males, 23 females), the age range was 19-60 years old, and the median age (interquartile range) was 38 (31, 46) years old. The level of IL-6 was detected by flow fluorescence microsphere method, the concentration of PCT was detected by immunochromatography, and the levels of T lymphocyte subsets and TIGIT were detected by flow cytometry. The differences and correlations between the detection indicators in each group were compared, logistic regression was used to analyze the factors influencing the progression of Crosne's disease and the clinical value of each detection indicator was analyzed by ROC curve. The results showed that there were no statistically significant differences in age and gender among the control group, the remission group, and the active group (H=1.422,χ²=0.020;P=0.491, P=0.990); in the active group, IL-6 was 17.55(9.67, 21.72)pg/ml, PCT was 0.38(0.14, 0.43)ng/ml, CD3⁺CD4⁺ was 35.47%±6.01%, CD3⁺CD8⁺ was 30.50%±5.20%, TIGIT was 25.08%±6.30%; in the remission group, IL-6 was 8.46(5.21, 10.04) pg/ml, PCT was 0.26(0.11, 0.35) ng/ml, CD3⁺CD4⁺ was 37.62%±4.86%, CD3⁺CD8⁺ was 28.30%±5.28%, TIGIT was 34.22%±5.45%; in the control group, IL-6 was 6.13(3.57, 8.12)pg/ml, PCT was 0.17(0.10, 0.21)ng/m, CD3⁺CD4⁺ was 39.74%±3.94%, CD3⁺CD8⁺ was 26.59%±4.50%, and TIGIT was 37.64%±6.22%.There were significant differences in IL-6, PCT, CD3⁺CD4⁺%, CD3⁺CD8⁺%, and TIGIT among the three groups(H=58.688, H=18.003, F=9.600, F=8.124, F=65.059;P<0.001, P<0.001, P<0.001, P<0.001, P<0.001), Among them, IL-6 and TIGIT in the active group were significantly different from those in the remission group (P<0.001, P<0.001), and only TIGIT was significantly different between the remission group and the control group (P=0.007);Spearman correlation analysis showed that the expression of TIGIT on T lymphocytes was negatively correlated with the levels of IL-6; the results of Logistic regression analysis showed that IL-6, PCT and TIGIT were independent factors affecting the progression of Crohn's disease;Comparing the ROC curves of the active group and the remission group, found that TIGIT was significantly different from PCT, CD3⁺CD4⁺, CD3⁺CD8⁺(Z=4.011, Z=4.091, Z=4.157; P<0.001, P<0.001, P<0.001), no statistical difference with IL-6 (Z=1.193, P=0.233). Selected the combined detection of IL-6 and TIGIT with the best AUC area and Youden index, which shows that the clinical value is improved, the AUC area of IL-6+TIGIT was significantly different from that of IL-6 (Z=2.674, P=0.008). In summary, TIGIT of T lymphocytes and IL-6 detection may be valuable in the diagnosis and treatment of Crohn's disease, and the combined detection of TIGIT and IL-6 may be meaningful for evaluating the status of Crohn's disease.