Autoimmunity to articular collagen in patients with osteoarticular syndromes

We studied the occurrence of autoimmunity to articular antigens in 39 patients with noninflammatory osteoarticular syndromes and 60 controls. Cell mediated immunity (CMI) was measured by assaying for leukocyte inhibitory factor (LIF) in supernates of mononuclear leukocytes cultured with native human collagen (types I, II, or III) or proteoglycan monomer. After stimulation with type II collagen, but not other antigens, 27/39 patients and 13/60 controls had positive LIF assays (p less than 0.001). In controls, but not in patients, CMI was associated with positivity for the HLA antigen DR4. No patient had antibodies to native type II collagen. These findings may reflect normal responses to articular injury or suggest that CMI contributes to the pathogenesis of osteoarticular syndromes. But they also emphasize that peripheral blood reactivity is not a certain reflection of synovial immunopathology.