The pill made from donated gut bacteria that could prove significant for people who have severe reactions to even traces of certain foods

2022-04-12

Pills containing donated gut bacteria could help treat people with food allergies, a trial suggests.

The treatment is based on the theory that having the ‘wrong’ type of gut bacteria triggers an over-reaction of the immune system, which is the basis of an allergy.

It’s thought introducing ‘healthy’ bacteria from someone without allergies could reduce the over-reaction or even eliminate it.

Early data from a small trial has found that the bacteria capsules increased the amount of peanut the allergic participants could be safely exposed to — with one able to tolerate as much as eight times more than before.

Such an improvement could prove significant for people who have a severe reaction even to minute traces of certain foods.

An allergic reaction is typically triggered by foods which the immune system recognises as being ‘foreign’.

This causes the release of chemicals called histamines that lead to inflammation and symptoms such as itchiness, nausea, swollen lips and diarrhoea.

In some cases the reaction can cause difficulty breathing as airways narrow, and blood pressure can plummet (histamine causes blood vessels to rapidly expand) — which can be life-threatening.

The only ‘cure’ currently is immunotherapy, where small amounts of the allergen are given to patients in slowly increasing quantities to build tolerance. This doesn’t deal with the cause of the disease, it only trains the body to react differently.

It’s hoped that the pill could treat the underlying cause to lower or eradicate the chance of reaction.

It’s based on the theory that allergies are linked to the gut microbiome, the trillions of organisms inside us that play a vital role in our immune system; an imbalance in the types of bacteria in the gut may alter our immune responses.

Previous studies have found that mice given gut bacteria from human babies with allergies then develop allergic reactions. This approach, which uses bacteria taken from stool samples, is known as faecal-microbiota therapy (FMT).

The pills used for the trial were made with bacteria from samples donated by healthy volunteers who didn’t have an allergy. The material was filtered to remove pollutants and checked for harmful bacteria and viruses. It was then put into capsules to be swallowed.

The trial involved 15 adults (aged 18 to 33) with a peanut allergy severe enough to cause a reaction to just half a peanut.

Five were given an antibiotic to clear the existing bacteria in their gut, as well as the new treatment. The rest only had the capsules.

In the antibiotic group, after FMT, 60 per cent had a higher tolerance to peanuts, compared with 30 per cent in the pill-only group — although one person among these was then able to eat four whole peanuts.

The researchers also found that the participants whose tolerance improved also had higher levels of cells that prevent an allergic reaction and lower levels of those linked to an allergic response.

The results from the study carried out by Boston Children’s Hospital in the U.S. have yet to be published. However, FMT has previously been used to treat the bowel infection clostridium difficile successfully.

Professor Graham Roberts, a consultant in paediatric allergy at University Hospital Southampton NHS Trust, says: ‘We know that the immune system is affected by the bacteria in your gut. But the research is at a very early stage.’

He adds that the amount patients can tolerate varies — sometimes it might be half a peanut, other times up to four.

‘So it may just be a false positive. More research is needed.’

Daily Mail, 12 April 2022
; https://dailymail.co.uk