The active form of leflunomide, HMR1726, facilitates TNF-alpha and IL-17 induced MMP-1 and MMP-3 expression.

Background/aims: To elucidate the influence and mode of action of HMR1726 (the active metabolite of leflunomide) on TNF-alpha and IL-17 activated metalloproteinases expression in synoviocytes.

Methods: Synovial fibroblasts from RA and OA patients were stimulated with both cytokines and altered gene expression in the presence or absence of leflunomide was detected by microarray analyses and quantitative RT-PCR. Protein expression was detected by western blotting and commercial ELISAs.