The hygiene hypothesis of allergies and autoimmune conditions offers one explanation for why these disorders have been on the increase for the last few decades. Infectious diseases have declined greatly over the same time period. We no longer have the epidemics of cholera, yellow fever, typhoid, small pox, and many other microbial illnesses that plagued our ancestors. Perhaps our immune systems need some amount of infection in childhood for proper development. “Uneducated” immune cells may be more likely to attack our own tissues. This hypothesis was first published in 1989.
Along this line of thinking, some researchers have suggested that a chronic, mild infection could reduce the damage produced by autoimmune conditions. Helminthic worms have been chosen as the ultimate natural anti-inflammatories. These parasites live in the intestines and generally produce no symptoms. Reference 1 explains that helminths are regarded as “master manipulators of the host immune response”.
I reported in July, 2010 about a clinical trial using helminths to treat multiple sclerosis. There are two new developments in helminth research:
1. A case study from the University of California reported that a patient with ulcerative colitis used Trichuris trichiura (a type of helminth known as whipworm) to treat his symptoms. His disease went into remission, and colonoscopy examination showed improved mucus production in the intestinal lining.
2. A clinical trial using helminths to treat adult autism is recruiting participants. The Mount Sinai School of Medicine in New York is conducting this study with the assumption that the worms can reduce neuroinflammation.
Helminthic therapy is not yet approved by the U.S. Food and Drug Administration for any condition, but it is advertised on the Internet. Researchers in the UK suggested data from animal studies and human clinical trials may be useful in developing new anti-inflammatory drugs to mimic what the helminthic worms do naturally. It is assumed that helminths secrete molecules to inhibit the human immune system and ensure their own survival as parasites. Perhaps someday these molecules will be available in the form of a pill rather than a worm egg.
References:
1. Figueiredo CA et al, “Chronic intestinal helminth infections are associated with immune hyporesponsiveness and induction of a regulatory network”, Infection and Immunity 2010 July; 78(7): 3160-67.
2. Broadhurst MJ et al, “IL-22+ CD4+ T cells are associated with therapeutic trichuris trichiura infection in an ulcerative colitis patient”, Sci Transl Med. 2010 Dec 1; 2(60): 60ra88.
3. Harnett W et al, “Helminth-derived immunomodulators: can understanding the worm produce the pill?” Nat Rev Immunol. 2010 Apr; 10(4): 278-84.
4. Helminthic therapy for multiple sclerosis:
https://www.empowher.com/multiple-sclerosis/content/helminthic-therapy-autoimmune-disease
Linda Fugate is a scientist and writer in Austin, Texas. She has a Ph.D. in Physics and an M.S. in Macromolecular Science and Engineering. Her background includes academic and industrial research in materials science. She currently writes song lyrics and health articles.