The last few lectures Dr. Cohen had talked about the use of helmith (worms) to treat certain inflammatory diseases such as Crohn’s disease. I thought this was very interesting and decided to do a little more research and expand on it.
There’s a vast amount of literature of the use of helminth as a therapeutic approach to autoimmune diseases causing chronic inflammation and allergies. Helminths are multicellular parasites that have typically co-existed with humans. Most are infectious and are found to be in two phyla, Platyhelminths (includes tapeworms and digenean flukes) and Nemotoda (roundworms). In well established populations with modern care helminthes infection is rare; however, about one million people worldwide are infected with most victims living in sub-Africa, Asia, and Latin America.
Recent studies have found a correlation in the decrease of infectious diseases and an increase incidence of other diseases such as allergies and autoimmune diseases in westernized countries. It is thought that because we have naturally co-evolved with helminthes humans have adapted and relied on helminthes to regulate our immune system.
Helminth infection is characterized by its ability to induce a regulatory T cell response and a strong Th2 response (driving the immune system to produce antibodies). In order for helminth to survive, it must escape its host immune system by secreting chemokines to block neutrophil migration and down regulate T and B cell response by activating Treg or induce anti-inflammatory cytokines. Therefore, one hypothesis is that with improved hygiene the rate of helminthes infection decreases increasing the rate of allergies and autoimmune diseases, and is thought to be due to an over production of Th1 immune response. It can be concluded that having some sort of helminth infection at one point in life helps to teach the immune system to balance its immune response.
Interestingly, helminth Trichuris suis (pig whipworm) therapy has been found to decrease disease activity in people with Chrohn’s disease and ulcerative colitis. Because T. suis does not infect humans, its eggs are eliminated after several weeks of colonizing. Other helminth may have therapeutic benefits, but are found to infect humans and cause mild to severe infection or raise public health concerns. Patients who were given T. suis found either temporary relief or decreased disease activity. The skewing of a Th2 response reduces Th1 (the inflammation and cytoxtic killer T cell response). Treating patients with chronic intestinal inflammation with helminth may be beneficial; however, the disadvantage of helminth infection is the difficulty in not only treating or fighting diseases that require Th1 response (example: HIV, tuberculosis, or malaria), but stimulating vaccines requiring an efficient Th1 response.
There are still debates and studies conducted to see if there is a relationship between helminthes and allergies. Some state that infection reduces allergies while others find the opposite. It is possible that age, genetics, and helminth species is the cause to the inconsistencies. Therapy with helminth in gastric autoimmune diseases by far seem to be consistent; however, further studies are being conducted to test whether other autoimmune diseases such as lupus and arthritis can also be treated.
Source:
World J Gastroenterol (2008) 14(33): 5125-5132
Parasitol Res (2007) 100:921–927
Immunobiology (2007) 212:475-490
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I recently saw a talk where they had data to show that people eating a high fat, low carbohydrate diet had reduced inflammatory bowel symptoms. I wonder if the high fat diet would have an effect on the immune system (such as the worms obviously would) or if it is more related to the body's reaction to the molecules being eaten, which also might involve the immune system? Why would carbohydrates be more inflammatory? Does it have something to do with carbohydrate epitopes being able to stimulate the innate immune system and not needing T cell help to cause inflammation?
I found this article very interesting. How would the worms get into your system? Do you digest them? Is this something you can go and see your regular doctor for or a specialist?
I thought that this was interesting, but halfway through I started to get confused. So are helmiths good parasites or bad parasites? At first it seemed like they were beneficial...
This article specifically talks about helmith as parasites that are able to escape the body's immune surveillance and live in their host, in this case humans. Helmith can enter a person’s body through the mouth, nose, and anus and is done by contaminating food, water, feces, animals, and objects with their eggs. Once helmith eggs are in the system, the eggs hatch grow, and divide. They live off their host, slowly depriving their host’s nutrient absorption. Helmith are smart in that they are able to adapt to their host immune response by “tricking” the immune system to prevent the helmith from being kicked out of the body. It does this by secreting cytokines that are similar to humans and manipulate the human immune response to Th2 instead of Th1. A Th1 immune response would cause inflammation to occur causing a cascade of events that activate macrophage and dendritic cells to eat up helmith and present it to T cells, which would then cause further events to rid the worms. Therefore, to prevent this from happening, helmith induces a Th1 response, producing antibodies that don’t seem to affect helmith survival too much. Depending on the species their life span is 2-6 years. People who get helmith infection can be asymptomatic, but sever infections can cause abdominal pain, diarrhea, nausea,rectal prolapse, and/or bowel obstruction. Diagnosis can be done by stool examination. The article however, talks about using a helmith (Trichuris suis) that infects pigs only. Patients with Chrohn’s disease and ulcerative colitis are treated with Trichuris suis eggs. The eggs are able to stimulate the human immune system to produce a Th2 response but are fortunately not able to survive in the human gut. Doctors routinely treat Chrohn’s or ulcerative colitis patients with T. suis, but it is a therapy to look into if other medications aren’t working.
In general, parasites are “bad” in the sense that our immune system tries to fight them off; however, I think that what is bad must also do some good to a normal immune system. Meaning that parasites can teach the immune system to balance an immune response or prevent other parasites from invading.
As far as the high fat and low carbohydrate diet and inflammation comment, I’ve heard that a diet rich in fat increases inflammation. I believe someone did a blog on it relating to obesity. As far as carbohydrates contributing to inflammation, I’m not quite sure about that I’ll have to do some research; however, I do know that there are some people who are allergic to gluten. People with this problem are diagnosed with Coeliac disease and have a hard time digesting wheat, barely, and rye. Overtime they develop inflammation in their gut which eventually tears up their lining.
I found the treatment of Chrons with worms very interesting. I had a friend very sick with the disease and I wonder if taking some of the pig worms would have helped her heal a little better, or even prevented her from getting sick.
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