IGE ANTIBODIES SPECIFIC FOR CARTILAGE COLLAGENS TYPE-II, TYPE-IX AND TYPE-XI IN RHEUMATIC DISEASES

Serum samples from 149 patients with RA and other rheumatological dise ases, and 57 non-arthritic controls have been assayed for IgE antibodi es to the cartilage collagen types II, IX and XI in their native and d enatured state. Using an improved ELISA technique together with antige n-binding inhibition studies to confirm specificity, 10 of the 149 (7% ) patients showed IgE antibodies to human collagen type II and bovine collagen types II, IX or XI. Some patients responded to only one, coll agen type whereas others had IgE positive responses to two or all thre e collagen species, Most of the IgE responses detected were directed t owards the denatured collagens. Those sera showing an IgE response to bovine type II collagen produced a similar response to the human equiv alent, including two patients with SLE. None of 57 control subjects de monstrated IgE specificity for any of the cartilage collagens. Patient s with IgE specificity for the cartilage collagens did not demonstrate IgM or IgA specificity for these antigens, but two of these patients showed IgG responses to type II and XI collagens. Whereas eight patien ts were exclusively IgE-positive for the cartilage collagens, others e xpressed specificities for IgG, IgM or IgA. It therefore appears that the specific autoimmune profile for each patient is often different fr om others, both in terms of the class of immunoglobulin expressed and the collagen antigens recognised. At present no correlations were obse rved between the IgE-positive patients and their clinical assessment a nd/or prognosis.