Worms: The Answer To Immune Problems?

July 3, 2008

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There have been several articles recently about how worms may be good for you, not the kind in the soil but those that are parasites in the human body. The idea is that worms (helminths) may help calm the immune system.

What makes the perfect parasite? For those that want to survive in the body, it is stopping the body responding and attacking you, or trying to get rid of you. A happy parasite wants a happy host.

Further some organisms end up in a symbiotic relationship. Symbiosis is often defined as a relationship where there is benefit to both participants.

So what do immune-dreived health problems have to do with worms?

In order to stay in the digestive tract many worms suppress parts of the immune system. This way the body does not try to attack the worms. So when infected with worms the body will turn down some (but not all) immune responses. This is not a new idea, it has been known for quite a while.

What is new is the suggestion the body got used to having the worms and was in balance with them. So that in modern times with improvements in sanitation and medication, when we lost our worms our immune systems got out of whack and in some people got revved up. In other words perhaps it was of a symbiotic relationship, beneficial to all.

Why has this new idea been proposed?

One thing that everybody agrees on is that in recent times there has been a huge increase in immune diseases ranging from hay fever to inflammatory bowel disease. These are all diseases where the immune system becomes more active.

So, of course, this leads to the question, why has there been this very sudden increase in a wide range of immune diseases?

There are all kinds of theories. One is the hygiene hypothesis. The idea is that being no longer exposed to certain bacteria, fungi, worms etc., that our immune systems are not trained properly, and may in many people get out of control.

One of the first demonstrations of role of worms was the experimental infection of 29 patients with active Crohn’s disease (an inflammatory bowel disease) with pig whipworm. An amazing 23 patients showed improvement, with 21 of these going into remission. Gut 54:87-90, 2005 (PubMed). Later studies have shown good results with ulcerative colitis, another inflammatory bowel disease.

Are we going to be getting worm egg prescriptions in the future? Unlikely. There is now a push to find the range of mechanisms that the worms use to suppress the human responses. It is very likely that drugs based on this knowledge will be tested for use on many diseases that have an inflammatory component. These will include hay fever, asthma, eczema, multiple sclerosis and the inflammatory bowel diseases. It will also include diseases that you might not realize involve immune responses such as diabetes and atherosclerosis (blocking of arteries).

photo credit: moneydick The image is of Caenorhabditis elegans a harmless roundworm that lives in the soil.