Viruses and autoimmune disease--two sides of the same coin?

Some viruses have the ability to modulate the development of autoimmune diseases. Virus infections have long been associated with the exacerbation of autoimmune disease, however, there is also evidence that viruses can actually protect against autoimmune disease. Several experimental models have been developed to investigate how some virus infections can prime for and trigger autoimmunity whereas others ameliorate the pathway leading to clinical disease. It is possible that the type I interferons, via interleukin 12, provide the link between viruses and autoimmunity.