IL-25 treatment of fibroblast-like synoviocytes (FLS) from RA patients inhibits p38 phosphorylation whereas IL-25 pretreatment downregulates the phosphorylation of STAT3, p38 and IκB-α triggered by IL-22 stimulation in FLS from RA patients (82). Here, STAT3 is linked to rheumatoid arthritis.