Reactivity of monoclonal anti-type II collagen antibodies with cartilage and synovial tissue in rheumatoid arthritis and osteoarthritis.

Monoclonal antibodies to 3 different epitopes on native type II collagen were used for immunohistochemical analysis of antigenic determinants that are exposed in the cartilage and synovial tissue obtained from patients with rheumatoid arthritis (RA) and osteoarthritis (OA). Two of the monoclonal antibodies reacted with cartilage from both OA and RA joints, but not with that from normal joints. The third monoclonal did not stain any of the cartilage sections. The 2 positive antibodies also reacted with cartilage fragments in the synovial tissue of both RA and OA joints, and in RA pannus tissue, the antibodies showed intracellular staining in many class II transplantation antigen-expressing synovial cells lying close to the damaged cartilage.