Our study was designed to investigate the role of mast cells in an experimental arthritis.

We used antigen induced arthritis in mast cell deficient mice and their normal littermates for this purpose. Both the severity and chromcitv of infiltrate, exudate and tissue swelling appeared to be similar when the primary arthntis was examined. Cartilage damage as a result of chronic inflammation occurred to a lesser extent in masi cell deficient mice. The flare reaction of anti gen induced arthntis was significantly less vehement in mast cell deficient mice considering tissue swelling, but only tendentiously different when the exudate was scored. Our results indi cate that mast cells contribute to cartilage damage and may play an enhancing role in the flare reaction of arthritis in mice.(J Rheumatol 1988, 15: 544-551)