Immunopathologic Significance of Cartilage Antigenic Components in Rheumatoid Arthritis

Abstract

Patients with rheumatoid arthritis have been studied in an attempt to detect immune responses to cartilage antigens that might function in the causation and/or perpetuation of joint inflammation. Cartilagenous antigenic determinants could be consistently demonstrated in synovial fluid and its phagocytic cellular components. Antibody to such constituents could not be detected in serum, synovial fluid or immunoglobulin eluted from or synthesized de novo by rheumatoid synovium. However, delayed hypersensitivity to cartilage antigens correlating with clinical evidence of inflammatory cartilagenous degradation could be identified.

Immunopathologic Studies in Relapsing Polychondritis

“…Transformation to one or more cartilage antigens was noted however, in 9 of 12 of the rheumatoid patients. Response of 5 of 12 patients to PG was positive with a mean incorporation of 4.0 times control; 3 of 12 responded to PP-L, mean response of 6.6; 7 of significance of degradation products of cartilage as regards causation and perpetuation of rheumatoid joint inflammation will be published independently (23).…”

Mammalian eyes and associated tissues contain molecules that are immunologically related to cartilage proteoglycan and link protein.

“…Immunity to purified cartilage proteoglycan has been demonstrated in patients with relapsing polychondritis (57,58) and rheumatoid arthritis (59,60) . Patients with relapsing polychondritis (61) often suffer from anterior uveitis.…”

Cartilage proteoglycan‐induced arthritis in BALB/c mice. Antibodies that recognize human and mouse cartilage proteoglycan and can cause depletion of cartilage proteoglycan with little or no synovitis

“…Proteoglycan (PG) and collagen, which are major structural components of the extracellular matrix of articular cartilage, have been implicated in autoimmune mechanisms leading to the development and/or persistence of inflammatory diseases in humans, such as rheumatoid arthritis, ankylosing spondylitis, and relapsing polychondritis (1)(2)(3)(4)(5)(6)(7). The injection of type I1 collagen from cartilage produces polyarthritis in genetically predisposed strains of rats (8,9) and mice (10).…”