Autoimmunity to Collagen

Thirty-one patients with seronegative psoriatic arthritis, 27 patients with rheumatoid arthritis, 10 with psoriasis alone, and 20 normal volunteers were studied for autoimmunity to human collagens. Cellular and humoral responses were frequently observed in the 2 groups with arthritis, but the subjects without arthritis did not display reactivity to native collagens. These data demonstrate that collagens function as autoantigens in both psoriatic and rheumatoid arthritis.