Association between IL‑33 and other inflammatory factors in patients with rheumatoid arthritis and in fibroblast‑like synoviocytes <i>in vitro</i>
Jing Wu, Qiang Li, J. S. Deng, Jinjun Zhao, Qinghong Yu
Abstract
IL‑33 is a member of the IL‑1 family of cytokines whose role remains controversial in rheumatoid arthritis (RA). The present study was performed to evaluate the correlation of IL‑33 with other cytokines and chemokines in serum and the synovia, and to explore the nature of the association. The concentration of IL‑33 in samples from 96 patients with RA was analyzed. The response of fibroblast‑like synoviocytes (FLSs) to treatment with different concentrations of IL‑33 was assessed <em>in vitro</em>. IL‑33 was indicated to exhibit an association with multiple cytokines and chemokines in synovial fluid with an inverted‑U‑shaped trend, including IL‑6, IL‑1β, IL‑8, MIG and IP‑10, but not in the serum. Furthermore, <em>in vitro</em> experiments confirmed that IL‑33 also exerted a U‑type dose‑dependent regulatory effect on FLS function. In addition, the data‑points do not exactly follow the U‑shaped curve fit in most cases, therefore, the applicability of this mathematical model in clinical practice is limited.