Peanut allergy potentially cured by oral therapy

28 January, 2015

A treatment for peanut allergies may provide a long-term cure for allergy sufferers.

Over 60 peanut allergic children in a study run by Murdoch Children's Research Institute were either given a dose of a probiotic, Lactobacillus rhamnosus, together with peanut protein in increasing amounts, or a placebo over 18 months to assess whether they would become tolerant to peanut.

The probiotic was a fixed daily dose, while the peanut oral immunotherapy was a daily dose of peanut protein starting at very low doses followed by a dose increase every two weeks until the maintenance dose (2 grams peanut protein) was reached. At the end of the treatment, the child's ability to tolerate peanut was assessed by a peanut challenge performed two to five weeks after stopping treatment.

'Modifying' allergic response

Remarkably, researchers found over 80 per cent of children who received the oral immunotherapy treatment were able to tolerate peanut at the end of the trial, compared to less than 4 per cent of the placebo group. This is 20 times higher than the natural rate of resolution for peanut allergy.

23 of 28 (82.1 per cent) probiotic-treated children and one of 28 (3.6 per cent) placebo-treated children were able to include peanut in their diet at the end of the trial. The likelihood of success was high – if nine children were given probiotic and peanut therapy, seven would benefit.

Lead researcher A/Professor Mimi Tang said the study results of the combined delivery were extremely exciting.

"Combined delivery of probiotic and oral immunotherapy was a safe and effective treatment for peanut allergy," A/Prof Tang said.

"The likelihood of success was high – if nine children were given probiotic and peanut therapy, seven would benefit."

"It appears that we have been able to modify the allergic response to peanut such that the immune system produces protective responses rather than a harmful response to the peanut protein."

The need for a curative treatment is greatest for peanut allergy since this is usually lifelong, and is the most common cause of fatality due to food-induced anaphylaxis.

Further research is now required to confirm whether patients can still tolerate peanut years after the study has finished.

'Don't try this at home'

A/Prof Tang cautioned about giving the treatment only under close medical supervision.

"Some families might be thinking about trialling this at home and we would strongly advise against this. In our trial some children did experience allergic reactions, sometimes serious reactions," she said.

"For the moment this treatment can only be taken under the supervision of doctors as part of a clinical trial."