Helminthotherapy

Helminthotherapy is the stimulation of the host immune system using certain helminths, especially nematodes, to aid in the treatment of inflammatory and autoimmune diseases. The relationship between the development status of countries and the assocaited health profile is extremely complex. The prevalence of autoimmune diseases is extremely low in underdeveloped countries where helminth infections are common. On the other hand, in developed countries, the frequency of autoimmune and chronic inflammatory diseases has increased significantly in the last century. The rise in hygiene standards causing reduction in helmintic infections, is thought to play a role in the increased incidences of inflammatory diseases. This observation has led to “hygiene” and “old friend” hypotheses claiming that some organisms in abundant amounts in the human microenvironment are necessary for the development of a healthy immune system and are associated with immunomodulatory or immune-repressive effects. According to these hypotheses, a decrease in exposure to certain organisms, especially parasites, has caused an increase in immune-mediated diseases. Helminths use a range of immunomodulatory mechanisms that affect the host immune responses, in all aspects, to maintain their persistence within the host. Helminth can skew immune response from TH1 to TH2 phenotype, increase both T- and B-regulatory cell levels, and decrease inflammatory cytokines release. This broad-spectrum modulation of the host immune system has both intended and undesirable consequences. Thanks to this modulation, the host benefits from the suppression of allergic, autoimmune and inflammatory reactions as well as suppression of parasitic damage. The suppressive and regulatory effects of helminths on both acquired and innate immune systems have led to many investigations on their use for treatment purposes. In addition to studies showing the effects of anti-helminthic treatment in enhancing atopic manifestations and inflammatory diseases, helminths have also been shown to have protective effects in animal models of allergy and autoimmune disease. Many studies following this data obtained from animal studies still continue today to both identify helminthic immunomodulatory molecules and to test implementability of helmintotherapy for human diseases