The clinical expression and significance of inhibitory receptor TIGIT gene on peripheral NK cells in rheumatoid arthritis / 中华检验医学杂志

ABSTRACT

Objective To investigate the expression of inhibitory receptor TIGIT gene in peripheral NK cells of patients with rheumatoid arthritis (RA) and its clinical significance. Methods A case control study was conducted of 58 RA patients(30 patients with active RA disease, 28 patients with remission of RA) and 22 healthy controls (HC) in the department of rheumatology and immunology from Affiliated Hospital of Jiangxi University of Traditional Chinese Medicine during December 2018 to June 2019, the related clinical data were collected. Flow cytometry was used to compare the expression of TIGIT gene on peripheral NK cells. The IFN-γ secretion level of cytokines in peripheral blood was detected by ELISA, and analyzed the correlations between TIGIT gene and disease activity and IFN-γ level. T-test or non-parametric test was used for comparison between the two groups, and Pearson correlation analysis was used for correlation between the two variables. Results Compared with HC group, the number of NK cells in RA disease group was reduced, which was (13.88 ± 4.56) × 107 cells/L in RA disease group and (25.69 ±2.48) ×107 cells/L in HC group (t=-2.036, P=0.041). The percentage of TIGIT gene expression in peripheral blood NK cells was not statistically different between RA disease group (39.73 ± 9.37) ％ and HC group (45.64 ± 9.91) ％ (t=-1.241, P=0.218). However, the average fluorescence intensity (MFI) of TIGIT gene expression was decreased, which was (7.21±2.03) in RA group and (9.01±3.29) in HC group (t=-2.947,P=0.004).MFI of TIGIT gene in NK cells of the disease active subgroup was (6.72±2.01), lower than that of the disease remission subgroup (8.75 ± 2.64), (t=-3.316, P=0.002), and MFI of TIGIT gene in NK cells of the disease active subgroup was negatively correlated with DAS28 score (r2=0.6496, P<0.0001).The secretion level of IFN-γcytokine in the RA disease group was (67.13±14.84) pg/ml, higher than that in the HC group (57.21 ± 14.23) pg/ml (t=2.757, P=0.017), and the secretion level of IFN-γ cytokine in the disease active subgroup was negatively correlated with the MFI of TIGIT gene on NK cells (r2=0.6622, P<0.0001). Experimental results of peripheral blood mononuclear cell stimulation in the RA disease activity subgroup showed that the secretion level of cytokines IFN-γwas reduced after stimulation compared with that before stimulation (t=11.38, P<0.0001). Conclusion The abnormal expression of TIGIT gene on peripheral NK cells are observed in patients with RA, which correlate with disease activity and IFN-γsecretion level.