A small group of UK children with peanut allergy were successfully treated in a desentization trial bringing closer the hope that a cure will one day be possible. The children were gradually given increasing amounts of peanut flour then peanuts until they were able to eat at least 10 whole peanuts without having an allergic reaction.
The trial was led by A T Clark of Cambridge’s Addenbrooke’s Hospital and is published as a study in the 17 February online issue of the journal Allergy.
The researchers emphasized that people with peanut allergy should not try to do what they did in the trial: medical supervision is important because there is a real risk that a person will react and need emergency treatment, as did one child in the early stages of this trial.
According to the British Nutrition Foundation peanut allergy can be severe and life threatening. It is quite common and affects about 1 in 200 people in the UK and rarely goes away over a person’s lifetime. Reactions range from itching, rash and swelling to difficulty breathing and severe asthma.
There is no treatment for the condition and research like this study is an important step toward the development of a cure.
In this study Clark and colleagues investigated whether peanut oral immunotherapy (OIT) could help children develop tolerance to peanut protein. They recruited four peanut-allergic children and first gave them a clinical exam to confirm their allergy and establish the dose of peanut protein that would be enough to cause a reaction (their dose threshold).
The children then had daily single-dose treatments of peanut flour with the dose increasing by a small amount twice a week. The first dose contained 5 mg of peanut protein and the final dose contained 800 mg.
After 6 weeks of treatment they underwent a second clinical assessment to establish whether their dose threshold had changed, and then they continued with the daily treatment.
The results showed that:
- The first assessment showed the children had dose thresholds ranging from 5 to 50 mg (between one fourtieth and a quarter of a peanut).
- One child reacted with anaphylaxis during the assessment and had to have an adrenaline injection.
- All the children tolerated the increasing dosage up to the 800 mg peanut protein level and none needed an adrenaline injection.
- Each child was able to tolerate at least 10 whole peanuts (about 2.38 grams of protein) in his or her threshold re-assessment.
- This means the threshold went up at least 48-, 49-, 55- and 478-fold for the four children respectively.
Clark and colleagues concluded that:
“We demonstrated a substantial increase in dose threshold after OIT in all subjects, including the subject with proven anaphylaxis.”
“OIT was well tolerated and conferred protection against at least 10 peanuts, more than is likely to be encountered during accidental ingestion,” they added.
Lead author and consultant allergist Pamela Ewan told The Times that the study offered hope for peanut allergy suffers:
“Until now there has been no treatment that has modified the disease. There has only been effective management of the problems,” said Ewan.
Although scientists don’t like to talk of “cures”, that is what they aim for, she added, explaining that:
“If you can switch off the allergy, you can claim you have cured the person.”
“Successful oral tolerance induction in severe peanut allergy.”
A. T. Clark, S. Islam, Y. King, J. Deighton, K. Anagnostou, P. W. Ewan.
Allergy Published Online: Feb 17 2009.
DOI: 10.1111/j.1398-9995.2009.01982.x
Please also see Desensitizing Children With Peanut Allergies published on 16 Mar 2009.
Sources: Journal abstract, British Nutrition Foundation, Timesonline.
Written by: Catharine Paddock, PhD