James Cook University and The Prince Charles Hospital
Status: results pending
A new trial moves closer to discovering how a tiny gut parasite could benefit people with coeliac disease.
The results are in from the latest international trial investigating the links between hookworm infection and improved gluten tolerance in coeliac disease patients. And while there’s no magic pill, the humble little worm may offer useful insights.
The trial explored the exciting theory that certain hookworm secretions may suppress the detrimental inflammation seen in coeliac disease. In a smaller 2015 trial, researchers found that coeliac disease patients infected with hookworms could tolerate the gradual reintroduction of small amounts of gluten to their diet, with no ill effects.
This much larger two-year trial, published in November 2020 in the journal Clinical and Translational Gastroenterology, involved 54 patients with coeliac disease in Townsville, Brisbane and Christchurch, New Zealand. Some were treated with 20 or 40 microscopic Necator americanus (human hookworm) larvae, and others with a placebo, both applied to the skin.
The trial was headed by James Cook University senior research fellow and immunologist, Dr Paul Giacomin, and was partially funded by a 2016 research grant from Coeliac Australia, awarded to Dr Giacomin and gastroenterologists Dr John Croese and Dr Tony Rahman from the Prince Charles Hospital, Brisbane.
After 12 weeks had been allowed to establish a hookworm infection, the participants swapped from a strictly gluten free diet to a 30-week series of various gluten challenges: first a 12-week phase of low-level gluten consumption (two spaghetti straws per day) then intermittent challenges of 25 spaghetti straws over 12 weeks, finishing with a sustained dose of 60 straws daily for six weeks.
The researchers had hoped that in this final phase, the hookworm-infected participants would have established tolerance to sustained gluten consumption, proving that hookworms could provide a cure. Unfortunately, this didn’t happen. There was little difference between the placebo and hookworm-infected groups, with around half of both tolerating the sustained gluten consumption phase well.
But while proof of a cure remains elusive, there were some other intriguing results.
The hookworm-treated participants tended to have improved tolerance to lower doses of gluten, with fewer coeliac symptoms and improved quality of life survey scores not seen in the non-infected participants. These results echoed two previous JCU-led trials with hookworms.
It’s a strong indication that there’s more to discover about the potentially beneficial effects of hookworms for those with coeliac disease, and the study has yielded valuable information for ongoing studies.
“We now have a goldmine of samples to investigate how these worms affect the human body in the context of coeliac disease and other inflammatory conditions,” says Dr Giacomin.
It’s a promising line of enquiry being explored by other JCU researchers such as Professor Alex Loukas, and worldwide groups.
Dr Giacomin and his co-researchers look forward to exploring the fruits of the latest trial in their continuing efforts to unlock the therapeutic potential of hookworms.
Printed in the March 2021 edition of The Australian Coeliac magazine