Helminth therapy for autoimmune disorders: Limitations and alternatives

Exaggerated immune responses to antigens of commensal or harmless environmental organisms, are the basis of autoimmune and allergic illness. Allergies and autoimmune disorders such as Type 1 Diabetes, Rheumatoid arthritis, Psoriasis/psoriatic arthritis, Multiple sclerosis, Systematic lupus erythromatosis, Inflammatory bowel disease, celiac disease are coextensive with the economic development around the globe. Some important allergic conditions that need immediate medical assistance such as asthma and allergic rhinitis have become ubiquitous in developed nations after industrialization era. The root cause of all the autoimmune disorders is still obscure but the fact that upbringing environment and nutritional status particularly can exacerbate the disease is irrefutable. A vast array of socioeconomic, dietary, environmental and genetic factors must underpin the disparity in disease profiles between different parts of the globe. Although most of the infectious disease conditions are linked to the poor sanitary conditions and lack of clean food and drinking water in developing countries but the threat of developing allergies and autoimmune diseases is more related to the developed part of world. Similarly, these disease are less common in childrens or adults belong to rural background than urban. The one reason attributed for less prevalence of autoimmune disorders in developing nations is continously evolving immune response of body due to exposure to various antigens at young age. The subject of whether parasites weaken their host's immune system in order to increase their own chances of survival and avoid the unwanted overreactions that lead to immunopathology has been raised. Therefore, in parasite-free conditions, the immune system may become more susceptible to autoimmune disease as the moderating impact of parasitic infections may be lost. One of such parasites are helminth species. These are multicellular enduring organism that are surviving on the earth for a long time. They are characteristically evolving with their host species and thus their infection has strong ability to influence and modify host response. Most common feature for helminth infection is chronic increase in parasitic burden and role of immune response of host in modifying pathology of parasite i.e. in less immunocompetent host the parasite will cause more pathogenesis. These parasites due to long evolution process has best modified themselves to invade host body as well as use host’s resources for their benefit. One such evolution is modifying Th2 regulatory immune response which act against gastrointestinal parasites and Th1 response against the other intracellular parasites. The question now arise is that whether helminth infection alone can lead to these differences in prevalence of autoimmune disorders, because if so we can identify the pathways helminths are using for host immune system modulation, as its knowledge can revolutionize the standard treatment protocol for above disease.