Why are autoimmune and allergic diseases on the rise?

An interesting paper just published in PLoS (Public Library of Science) clarifies one of the mechanisms that account for the recent increase in autoimmune disorders. The authors set out to investigate the possibility of an induced dysregulation of the immune system:

"Repeated immunization with antigen causes systemic autoimmunity... Overstimulation of CD4+ T cells led to the development of autoantibody-inducing CD4+ T (aiCD4+ T) cell[s]...[which became] antigen-specific cytotoxic T lymphocytes (CTL). These CTLs could be further matured by antigen cross-presentation, after which they caused autoimmune tissue injury akin to systemic lupus erythematosus (SLE)."

This essentially means that overexposure to a potential antigen (increased amounts of gluten in hybridized wheat, higher environmental levels of mercury, etc.) can result in sensitization of the immune system with cross-reaction to our own tissues (autoimmune disease). The authors clearly state their conclusion drawn from the evidence:

"Systemic autoimmunity appears to be the inevitable consequence of over-stimulating the host's immune ‘system’ by repeated immunization with antigen, to the levels that surpass system's self-organized criticality."