T cell proliferative response to type II collagen in the inflammatory process and joint damage in patients with rheumatoid arthritis

Objective. To investigate the role of T cell responses to type II collagen (CII) in disease progression in patients with rheumatoid arthritis (RA). Methods. T cell proliferative responses to bovine CII by peripheral blood mononuclear cells (PBMC) from patients with early RA (duration < 5 yrs) were assayed by mixed lymphocyte culture. Clinical and laboratory variables including erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) were examined at the time of sampling. Radiographic damage on hand radiographs was evaluated by the method of Steinbrocker and Sharp. Results. In a cross sectional study, patients (n = 22) with positive T cell responses (stimulation index 2 2) had higher levels of CRP and ESR than those (n = 21 ) not showing T cell responses. The number of damaged joints (by Steinbrocker's method) and damaged joint scores (by Sharp's method) were significantly higher in patients with positive T cell responses than in those without. The joint space narrowing scores correlated well with T cell responsiveness to CII. Patients (n = 15) with both positive T cell responses and RA-susceptible allotypes HLA-DR1 or DR4 had higher damaged joint scores than the remainder of the patients (n = 24). Conclusion. T cell proliferative responses to CII are associated with inflammatory activity and radiographic severity in RA. RA-susceptible allotypes positively relate to the radiographic progression associated with T cell responses to CII. Our data suggest that CII-reactive T cells may play a role in the pathogenic process of joint damage, especially in genetically susceptible patients.