Effect of psychological stress on the induction of arthritis in rats.

To determine whether emotional states could influence susceptibility to type II collagen-induced arthritis in rats, we studied the effects of experimentally produced psychological stress on the clinical, histologic, and immunologic manifestations of this autoimmune disease. Stress, induced by exposure to a cat, abrogated the development of arthritis in rats immunized with type II collagen. The incidence of arthritis was also decreased in rats subjected to transportation and handling. These environmental factors dissociated the development of humoral and cellular sensitivity to collagen from the occurrence of arthritis. This study provides a unique demonstration that psychosomatic processes can influence an animal mode of autoimmunity.