Frequency changes of peripheral blood interleukin-22+CD4+CD161+ T cells in rheumatoid arthritis

Objective To analyze the frequency of interleukin (IL)-22+CD161+CD4+ T cells in the peripheral blood mononuclear cells (PBMCs) in rheumatoid arthritis (RA) patients compared with healthy control subjects and investigate the relationship of IL-22+CD4+CD161+ T lymphocyte frequency changes with RA disease activity. In addition to explore the pathogenesis of RA, and to look for new treatment targets for RA. Methods Twenty-one RA cases were included in the Department of Rheumatology of Tangshan Gongren Hospital from 2017 to 2018. Fourteen patients were female and 7 were male with the age ranged from 36 to 74 years old.The average age of this group of patients was (55±10) years, the average disease course was (60±50) months. All patients fulfilled the classification criteria of American College of Rheumatology [American College of Rheumatology (ACR)]. Twenty-one subjects were enrolled as the control group, all of them came to Tangshan Gongren Hospital for regular health check-up. Fifteen subjects in the control group were female and 6 were male. Their age ranged between 40-78 years old with the average age of (55±9) years. IL-22+CD4+CD161+ T cells in PBMCs were detected by flow cytometry. The frequency variation of different CD4+CD161+ T was compared between case and control groups. The correlation was studied between the frequency and RA disease activity score (DAS28), tender joints number, swollen joints number, red blood cell sedimentation rate, high sensitive C reactive protein and white blood cell counts, red blood cell counts, platelet counts, IgG, IgA, IgM, complement C3 level, complement C4 level. T-test or Mann-Whitney U test were used for single-factor analysis, Pearson′s test was used for correlation analysis. Results The percentage of RA group secreted CD4+ T cells(0.33± 0.20)% of INF-γ and IL-22, CD4+ T cells(0.51±0.29)% of IL-22, and CD4+CD161+ T cells of IL-22 simultaneously. The number (0.55±0.28)% was significantly higher than that of the healthy control group [(0.22±0.14)%, (0.25±0.18)%, (0.36±0.24)%], and the differences were statistically significant [P=0.002, P= 0.0.45, P=0.026]. Conclusion The percentage of IL-22+ CD4+ CD161+ T lymphocytes in the peripheral blood monocytes in RA patients is significantly higher than that in the healthy controls. The results of this study suggest that IL-22+CD4+ CD161+ T lymphocytes in RA patients maybe related to RA disease activity and joint lesions. Key words: Arthritis, rheumatoid; CD4-positive T-lymphocyetes; CD161-positive T-lymphocyets; Interferon-gamma; Interleukin-22