More on the autoimmunity of osteoarthritis

A paper just published in the journal Clinical Immunology reminds clinicians that osteoarthritis occurs when there is a pathological immune response to articular cartilage. The authors state:

"Even though osteoarthritis (OA) is mainly considered as a degradative condition of the articular cartilage, there is increasing body of data demonstrating the involvement of all branches of the immune system."

Although mechanical trauma may be the initial trigger, an immune inflammatory attack on self-antigens drives the chronic joint damage and pain:

"Genetic, metabolic or mechanical factors cause an initial injury to the cartilage resulting in release of several cartilage specific auto-antigens, which trigger the activation of immune response. Immune cells including T cells, B cells and macrophages infiltrate the joint tissues, cytokines and chemokines are released from different kinds of cells present in the joint, complement system is activated, and cartilage degrading factors such as matrix metalloproteinases (MMPs) and prostaglandin E2 (PGE2) are released, resulting in further damage to the articular cartilage."

While attending to any biomechanical faults, osteoarthritis should be managed as an autoimmune disorder. Anti-cytokine therapies have not been as helpful for osteoarthritis as they have for rheumatoid arthritis, but the authors note that other interventions, including natural compounds derived from plants, are promising:

"There is considerable success in the treatment of rheumatoid arthritis using anti-cytokine therapies. In OA, however, these therapies did not show much effect, highlighting more complex nature of pathogenesis of OA. This needs the development of more novel approaches to treat OA, which may include therapies that act on multiple targets. Plant natural products have this kind of property and may be considered for future drug development efforts."

Practitioners who are up to date in the case management of autoimmune disorders will find that treating osteoarthritis demands a comprehensive investigation and treatment of underlying causes.