AsianScientist (Sep. 29, 2014) – Researchers have used hookworms to reduce the symptoms of celiac disease. The results, published in the Journal of Allergy and Clinical Immunology, are also good news for sufferers of other inflammatory conditions such as asthma and Crohn’s disease.
In the small trial run over a year, 12 participants were each experimentally infected with 20 Necator americanus (hookworm) larvae. They were then given gradually increasing doses of gluten: beginning with just one-tenth of a gram per day (the equivalent of a two-centimetre segment of spaghetti) and increasing in two further stages to a final daily dose of three grams (75 spaghetti straws).
“By the end of the trial, with worms onboard, the trial subjects were eating the equivalent of a medium-sized bowl of spaghetti, with no ill effects,” James Cook University (JCU) immunologist Dr. Paul Giacomin said.
“That’s a meal that would usually trigger a debilitating inflammatory response, leaving a coeliac patient suffering symptoms like diarrhoea, cramps and vomiting.”
Four participants withdrew in the earlier stages of the trial (for various reasons mostly unrelated to gluten) but the remaining eight experienced significant and ongoing benefits.
“The eight who stuck with the trial were able to increase their gluten tolerance by a factor of 60, a massive change,” said Professor Alex Loukas, head of the Center for Biodiscovery and Molecular Development of Therapeutics at JCU, and joint principal investigator of the study.
“We and others have had promising results in earlier trials but this is clear proof-of-principle of the benefits of hookworm in treating inflammatory disease,” Prof. Loukas said.
Significantly, all the trial subjects rejected the researchers’ offer of drugs that would eliminate the hookworms. “They all chose to keep their worms, and they continue to report good health. However they were instructed to return to a gluten-free diet after the trial,” Prof. Loukas said.
The potential of helminths (parasitic worms) in treating inflammatory diseases lies in their ability to dial back the human immune response, a skill that enables them to survive and thrive in the human gut, without compromising their host’s ability to fight off other infectious diseases.
“In gut biopsies collected before, during and at the end of the trial, we identified specific cells of the immune system, known as T cells, that we suspected were targeted by hookworm proteins,” Dr. Giacomin said. “We found that over the duration of the trial the T cells within the intestine changed from being pro-inflammatory to anti-inflammatory.”
The researchers believe that the key to the hookworm’s anti-inflammatory prowess lies within the proteins that the worms secrete. They are actively seeking these molecules for further research, with the ultimate goal of developing an entirely new class of anti-inflammatory drug.
“This trial has confirmed hookworms as our choice of parasite for clinical applications,” Professor Loukas said. “But despite our growing fondness for them, we do acknowledge that a protein pill will have broader market appeal than a dose of worms.”
The article can be found at: Croese et al. (2014) Experimental Hookworm Infection and Gluten Microchallenge Promote Tolerance in Celiac Disease.
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Source: James Cook University; Photo: Yasser/Flickr/CC.
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