Study on the relationship between T helper cells 22/interleukin-22 and rheumatoid arthritis with interstitial lung disease

Abstract

Objective To study the relationship between the T helper cells (Th22)/interleukin (IL)-22 and rheumatoid arthritis (RA) with interstitial lung disease (ILD), and to define the clinical significance of Th22 cells for RA. Methods The quantity of Th22 cells in the peripheral blood from 40 patients with RA (20 RA with ILD, 20 RA without ILD) were examined by flow cytometry, the level of IL-22 in the sera was detected by enzyme-linked immunosorbent assay (ELISA). Comparisons between groups were analyzed by t-test, rank sum test, and the correlation of parameters were tested by linear correlation analysis. Results The quantities of CD4+ IL-22+ cells (Th22) in RA patients [(0.15±0.07)%] were significantly higher than normal controls [(0.09±0.05)%] (t=4.097, P<0.01), and IL-22 levels in RA patients [(83±7) ng/L] were significantly higher than normal controls [(61±5) ng/L] (t=13.057, P<0.01). The quantities of Th22 cells in RA-ILD patients [(0.18±0.07)%] were significantly higher than RA-NILD patients [(0.13±0.05)%] (t=2.919, P=0.008), and IL-22 levels in RA-ILD patients [(87±6) ng/L] were significantly higher than RA-NILD patients [(80±6)ng/L] (t=3.624, P=0.001). The quantities of Th22 cells were positively correlated with erythrocyte sedimentation rate (ESR), rheumatoid factor(RF) and 1.4 disease activity score (DAS)28 (r=0.336, 0.377, 0.577, P<0.05), and the level of IL-22 were also positively correlated with ESR and DAS28 (r=0.406, 0.576, P<0.05). Conclusion The quantities of Th22 cells and IL-22 level are increased in RA patients, especially in RA-ILD patients. The quantities of Th22 cells and IL-22 level are positively correlated with ESR and DAS28. It may play a certain role in RA especially in RA with ILD. Key words: Arthritis, rheumatoid; Interleukin-22; Lung disease, interstitial; T-lymphocytes, helper-inducer