Key clinical point: Stimulation with IL-33 showed an increase in several mast cell lines in RA patients compared to controls, suggesting that inhibiting mast cells might be a therapeutic strategy to prevent joint deterioration in RA patients.
Major finding: Synovial tissues in RA patients showed more more c-kit- and FcεRI-positive mast cells, which are producers of both tryptase and chymase, compared to controls after stimulation with IL-33. In addition, IL-33-stimulated mast cells promoted more osteoclast differentiation than non-stimulated mast cells.
Study details: The data come from synovial fluid samples collected from 20 RA patients and 20 patients with osteoarthritis of knee joints who served as controls.
Disclosures: The study was supported in part by grants from the National Research Foundation of Korea. The researchers had no financial conflicts to disclose.
Source: Kim K-W et al. Arthritis Res Ther. 2021 Apr 21. doi: 10.1186/s13075-021-02491-1.