The interplay of epigenetics and epidemiology in autoimmune diseases: time for geoepigenetics

The etiology and pathogenesis of autoimmune diseases remains largely enigmatic despite numerous hints provided by basic science and clinical observations. We are convinced that similar factors and mechanisms may underlie different conditions, as well illustrated by the female predominance or the association with serum autoantibodies shared by different groups of patients. Genomic variability is largely insufficient to explain the individual susceptibility to systemic lupus erythematosus, rheumatoid arthritis, and systemic sclerosis. This is demonstrated by data from large genome-wide association studies and, more importantly, from concordance rates in monozygotic and dizygotic twins. Indeed, we are convinced that environmental factors are pivotal in determining the onset of autoimmunity and explaining the epidemiological variability in disease prevalence. Epigenetics (DNA methylation, histone changes, microRNA) represent the ideal link between environmental factors (gut microbiota, diet, infections and xenobiotics) and disease incidence and for this reason we propose that the parallel study of these areas should be coined geoepigenetics.