Type II Collagen Plays Key Role in Rheumatoid Arthritis
The protein binds to antibodies and plays significant role in progression of RA
FRIDAY, Dec. 2 (HealthDay News) -- When type II collagen (CII) is modified by oxidants present in rheumatic joints, it binds antibodies and plays a significant role in the progression of rheumatoid arthritis (RA), according to a study in the December issue of Arthritis & Rheumatism.
Ahuva Nissim, Ph.D., of the University of London, U.K., and colleagues analyzed serum samples from 31 patients with RA and 41 controls with other inflammatory joint diseases such as osteoarthritis and lupus. They observed binding with pure and natural CII and CII that had been modified with ribose and three oxidants found in the rheumatic joint: hydroxyl radical, hypochlorous acid and peroxynitrate.
While only one RA serum sample showed strong binding to natural CII, 14 of the 31 samples were binders to modified CII, including seven which were strong binders and seven which were moderate binders. For the non-RA serum samples, only one had a strong binding reaction to modified CII and five were moderate binders.
"We propose that the oxidative modification of CII, possibly in combination with proteolysis, creates a CII autoantigen. It is possible that in the inflamed joint, the abnormally high fluxes of reactive oxygen/nitrogen species give rise to chemical reactions to modify CII," the authors conclude.