Cartilage as a target of autoimmunity: A thin layer

The mechanisms determining the trigger of a cartilage-specific immune response, its development and outcome are poorly understood. Most likely, the distribution and concentration of a specific cartilage protein may play a role by eliciting an autoimmune response. Indeed, the inflammatory processes lead to tissue damage mediated by the intervention of several factors such as autoantibodies, cytokines as well as cells of the innate an adaptive immunity. For this reason, even previously-considered degenerative diseases, such as osteoarthritis, should now be re-evaluated as at least partly inflammatory-driven. Thus, the objective of this review is to describe the clinical conditions sustained by the immune-mediated reactions to cartilage, which represents the target organ in a number of autoimmune diseases.