Published Online: January 16, 2015
Currently there is no cure for food allergy. Management relies upon trying to avoid the food, and in some cases, carrying an epinephrine autoinjector (EpiPen) to treat severe reactions. A treatment that can induce tolerance—and which might lead to actually curing the food allergy—would be a major advance in care. Oral immunotherapy (OIT), which involves eating increasing amounts of a food allergen, has been explored as a strategy to induce tolerance. Although studies have shown that OIT with egg, milk, or peanut can induce desensitisation (i.e., the short term ability to eat a food allergen that is lost when OIT is stopped), it is uncertain whether OIT can induce tolerance (i.e., the long-lasting ability to eat a food even after OIT is stopped). In this month’s issue of The Journal of Allergy and Clinical Immunology (JACI), Tang and colleagues investigate a new type of treatment that combines a probiotic (a substance that stimulates the growth of microorganisms, especially those with beneficial properties) with OIT in children with peanut allergy, and test whether children are able to tolerate peanut after OIT is stopped.
The authors of this study conducted a trial in 62 children with peanut allergy. Children received either probiotic with peanut oral immunotherapy (PPOIT) or a placebo for 18 months. The probiotic was a fixed daily dose of Lactobacillus rhamnosus, while the peanut OIT was a daily dose of peanut protein starting at very low doses followed by a dose increase every 2 weeks. At the end of the treatment, the child’s ability to tolerate peanut was assessed by a peanut challenge performed 2 to 5 weeks after stopping treatment. The investigators also looked for a change in peanut skin prick test (SPT) results, and change in blood levels of peanut-specific antibodies.
Fifty-six children completed the trial. Possible sustained unresponsiveness (i.e. tolerance) was achieved in 23 of 28 (82.1%) PPOIT treated children and 1 of 28 (3.6%) placebo-treated children. The likelihood of success was high—if 9 children were given PPOIT therapy, 7 would benefit. Children who received PPOIT also had reduced peanut-specific antibody levels, suggesting that clinical effects were due a change in the allergic response to peanut. Importantly, the number of children that reported adverse events was similar in PPOIT and placebo groups, although one child did not tolerate PPOIT and treatment was stopped.
This study is important because it is the first double-blind, randomized, controlled trial (RCT) of a novel combined treatment involving probiotic and peanut OIT, and the first RCT in peanut allergy to perform a food challenge after stopping OIT. The treatment was highly successful, with just over 80% of children who received PPOIT able to eat peanut after stopping treatment as compared to less than 4% of children receiving placebo. Nine children need to be treated with PPOIT for seven to benefit. Before this treatment can be considered for patients, further work is required to see if tolerance is maintained in the longer term and to examine the individual effects of the probiotic and peanut OIT.
The Journal of Allergy and Clinical Immunology (JACI) is an official scientific journal of the AAAAI, and is the most-cited journal in the field of allergy and clinical immunology.