The nature and nurture of common autoimmunity.

Autoimmune diseases are a heterogeneous group of disorders where multiple alterations in the immune system result in a spectrum of syndromes that either target specific organs or affect the body systematically. Although their heterogeneity is due to a collection of diverse conditions based on epidemiology, pathology, or diagnostic criteria, the underlying immunogenetic mechanism might be similar. Herein the nature and nurture of autoimmune diseases considered as a trait are reviewed, and a discussion is given on their multifactorial characteristics.