Geo-epidemiology and autoimmunity.

Autoimmune disease (AD) affects approximately 3% of the population. This is an enormous number, but ironically the study of autoimmunity has not taken on the significance of many other diseases because so many of the ADs are relatively uncommon. Indeed, despite enormous advances in the diagnosis and the treatment of AD, there is still a paucity of data on the etiological events that lead to the clinical pathology. For most other human diseases, the etiology is addressed and often solved by the use of epidemiology. Epidemiology consists of the study of prevalence of a disease, coupled with analysis of genetic factors and detection of environmental agents. In the context of autoimmune conditions, preclinical epidemiology has recently been favored, as a consequence of the discovery that autoantibody precedes overt disease. The idea of a North-South gradient in the prevalence of ADs, with a reciprocal gradient in that of infectious injuries has proven to be debatable. More importantly, environmentally-induced changes have been shown to modify certain diseases giving rise to the key concept of epigenetics. However, it is clear that major voids exist. Some of these voids were hoped to be solved by the use of genome-wide associations. This, however, has proven very problematic, as the genetic basis of AD is considerably more complicated than once believed. We now base our hopes on next generational sequencing as a brut force undertaking to partially decipher the genetic code that predisposes individuals to AD. This volume is a compilation of papers in Autoimmunity Reviews and the Journal of Autoimmunity and presented as part of the 7th International Congress on Autoimmunity in Ljubljana, Slovenia. It is clearly impossible to present data on the geoepidemiology of all of the AD. Instead, we attempted to generate interest amongst immunologists to generate papers that are thought provoking but also contemporary reviews. Copyright 2009 Elsevier Ltd. All rights reserved.