SUPPRESSION OF AUTOIMMUNE RESPONSES AND INFLAMMATORY EVENTS BY LEFLUNOMIDE IN AN ANIMAL-MODEL FOR RHEUMATOID-ARTHRITIS

The effect of leflunomide (HWA 486) was tested in proteoglycan-induced arthritis in an autoimmune animal model showing many similarities to human rheumatoid arthritis and ankylosing spondylitis. The development of the disease in genetically susceptible BALB/c mice is dependent up on the expression of both cell-mediated and humoral immunity to host m ouse cartilage proteoglycan. Arthritic and control (non-arthritic) ani mals were treated with 35 mg leflunomide/kg body weight/day for 12 wee ks to suppress inflammatory events and antibody titers. Leflunomide su ppressed acute inflammatory events, protected animals from new inflamm atory episodes and acute exacerbations, slightly reduced the stiffness in joints and blocked the degradation of cartilage. The suppressive e ffect of leflunomide in proteoglycan-induced arthritis is due primaril y to the suppression of autoantibody formation.