Treating to re-establish tolerance in inflammatory arthritis - lessons from other diseases.

Therapeutic tolerance embraces the concept of 'switching off' immunopathology by specifically targeting elements of the immune system. It has been achievable in preclinical models of transplantation and auto-immunity for more than two decades; however, previous attempts to translate to the clinic have been unsuccessful. Nonetheless, an improved understanding of tolerance mechanisms, along with novel therapeutic agents and strategies, are starting to bear fruit in a number of disease areas. True tolerance is achievable in transplantation settings, and long-term remissions can be induced in various auto-immune and atopic conditions. Equivalent outcomes should be achievable in inflammatory arthritis, although this may require an improved understanding of the immune dysregulation that is intrinsic to rheumatoid arthritis (RA), and better definitions of RA autoantigens. Biomarkers of tolerance induction would rapidly advance the field in all therapeutic areas. This article summarises the advances made in other therapeutic areas, and the lessons learned that we can now apply to RA.