Infection and autoimmunity: are we winning the war, only to lose the peace?

It appears that, in developed countries, as we succeed in reducing the incidence of infections we could expose underlying predispositions to develop autoimmunity. This article outlines some of the potential mechanisms that are induced by infection and that prevent onset of autoimmunity, and particularly focuses on the autoimmune disease Type 1 diabetes. Studies on the protective effects of pathogens as diverse as parasitic hellminths and intracellular bacteria suggest the possibility that different classes of infectious organism mediate different protective mechanisms. Parasites and the mammalian immune system have evolved together to limit damage to host tissue, which is important to the host for self-maintenance and to the parasite, in some cases, to maintain its habitat and complete its life cycle. By understanding the mechanisms by which different classes of parasites modulate the host immune response, we might be able to devise therapeutic strategies for the treatment of autoreactive responses.