Are virus infections triggers for autoimmune disease?

Viruses have been implicated in the initiation, progression, and exacerbation of several human autoimmune diseases, including multiple sclerosis. However, no single virus has been demonstrated as the etiologic agent. Multiple different infections may be involved, first in priming the immune system for autoimmunity and then in triggering the actual disease. A model based on experimental allergic encephalomyelitis, an animal model of multiple sclerosis, has been developed, which shows that an initial early infection with a virus having molecular mimicry to self-epitopes can prime for disease that occurs after a subsequent non-specific immunologic stimulus, such as a different infection. The role of multiple infections in the development of autoimmune disease may explain why no one virus has been implicated.