The chronic inflammatory response observed in rheumatoid arthritis involves an exaggerated immune response to cartilage, connective tissue and synovial fluid, which in unaffected people are recognized as ‘self’.
The concept of ‘oral tolerance’ is based upon the ability of the mucosal immune system to effectively down-regulate the systemic immune system. Hence, with rheumatoid arthritis, the whole body is effectively mounting an immune response to type ll collagen. If this collagen is presented to, and processed by the mucosal immune system by oral ingestion of collagen, it will effectively communicate to the systemic immune system a down-regulated signal, which will then lead to a lower inflammation reaction.
This mechanism has been proven effective both in animals (Thompson et al., 1993. Stanes et al., 1996.) and in human trials (Trentham et al. 1993). To be effective, fine type ll collagen must be used and the dose needs to be very low – high doses do not produce the same response (probably producing anergy in the tolerance mechanism).