A longitudinal study of anticollagen antibodies in patients with rheumatoid arthritis.

Antibodies to native and denatured collagens (types I, II, IX, and XI) were measured in sequential serum samples collected over 1.5-8.7 years (median 4.3) from 15 patients with rheumatoid arthritis. Eleven patients were seropositive and 4 were seronegative. Disease duration ranged from 3 years to 25 years before the first sample was tested. The patients showed a selective and varying response to collagens, even after disease had been present for a long time. Changes in the levels of antibody to one collagen type were not necessarily linked to changes in the levels of antibody to other collagens. Only some patients showed a strong correlation between C-reactive protein levels (a measure of disease activity) and antibodies to individual collagens. These findings suggest that rheumatoid arthritis patients produce antibodies to a wide variety of epitopes on these collagen molecules, as a result of different antigenic epitopes being exposed by cartilage degradation at different times throughout the disease.