Limited proliferative response to type II collagen in rheumatoid arthritis.

In order to define the potential importance of type II collagen in the activation of rheumatoid arthritis (RA) synovial fluid (SF) lymphocytes, we examined the proliferative response of matched peripheral blood and SF lymphocytes to type II collagen. The mean proliferative response to the collagen was somewhat greater (p less than 0.05) with SF, compared to peripheral blood lymphocytes. However, the magnitude of this response was relatively weak as determined by stimulation indices, and it did not approach that observed with peripheral blood lymphocytes in response to tetanus toxoid. Sixty-seven percent of peripheral bloods and 50% of SF demonstrated positive responses to the control antigen, tetanus toxoid. In contrast, only 6 and 28%, respectively, were positive in response to type II collagen. The addition of exogenous interleukin 2 augmented responses to the tetanus toxoid, however, no such enhancement with type II collagen was noted in our patients. Our collagen was arthritogenic in experimental animals. These observations do not support the existence of T cell specificity toward type II collagen as a common mechanism for the expansion of synovial lymphocytes in RA.