[Group 2 innate lymphoid cells (ILC2) relieves pathogenesis of rheumatoid arthritis by secreting IL-13]

Objective To study the changes of group 2 innate lymphoid cells (ILC2) in rheumatoid arthritis (RA) and its possible mechanism. Methods The 28 joint disease activity score (DAS28) and peripheral blood samples were collected from RA patients. Erythrocyto sedimentation rate (ESR) and C-reactive protein (CRP) were measured by an automatic erythrocyte sedimentation device and immune transmission turbidimetry, respectively. Rheumatoid factor (RF) and anti-cyclic citrullinated peptide antibody (ACCP) were assessed by immunoturbidimetry and chemiluminescence assay, respectively. Flow cytometry was used to detect the proportion of ILC2 in the patients with RA. The correlations between ILC2 and the above disease indexes were analyzed by Spearman correlation analysis. RA patients were divided into two groups: low disease activity (DAS28<3.2) group and high disease activity (DAS28≥3.2) group. The expression of interleukin-13 (IL-13) in ILC2 of RA patients was detected by flow cytometry, and the differences of ILC2 expression were compared in RA patients with different disease activity of IL-13. Results Compared with healthy people, the proportion and absolute number of ILC2 in the peripheral blood of RA patients increased. ILC2 was negatively correlated with ESR, CRP and DAS28. IL-13 secreted by ILC2 in RA patients with high disease activity was significantly lower than that in the ones with low disease activity. Conclusion ILC2 inhibits RA disease activity by secreting IL-13.