The therapeutic potential of epigenetics in autoimmune diseases.

Autoimmune diseases now include over 100 conditions and are estimated to affect over 20 million people in the United States or 5% of the world population with numerous geographical differences coined as geoepidemiology. Further, concordance rates in monozygotic twins are significantly higher compared to dizygotic sets while being significantly below 50% for most autoimmune diseases. These lines of evidence suggest that additional mechanisms are needed to link the individual susceptibility with the proposed chemical and infectious factors in the environment. Epigenetics may well constitute this missing link to include DNA methylation, histone changes, and microRNA which contribute to the epigenome characterizing specific diseases. Importantly, these epigenetic changes may be ideal targets for new personalized treatments as suggested by data in cancer. A number of chemical and physical factors, along with proposed infectious agents or aging, are involved in the etiopathogenesis of autoimmune diseases through epigenetic changes. The most prominent evidence on the association between environment and autoimmunity has been reported in systemic lupus erythematosus, but similar mechanisms were proposed in rheumatoid arthritis, systemic sclerosis, and type 1 diabetes.