ALLERGY & IMMUNOLOGY: What’s new in food allergies

Part of Contemporary Pediatrics’ coverage of the 2015 AAP Annual Conference. For more coverage, click here.

Promising avenues for addressing peanut allergies include early-exposure preventive strategies, improved testing methods, and immunotherapeutic treatment approaches, said Robert A Wood, MD, FAAP. He spoke during a session titled “Diagnosis and Management of Food Allergy: What’s New?”

Published in February, results of the Learning Early about Peanut Allergy (LEAP) study are now being put into pediatric practice. The study showed that giving allergy-prone infants aged between 4 and 11 months at least 6g of peanut protein weekly greatly reduced the prevalence of peanut allergy at 60 months, 1.9% versus 13.7% in a control group that avoided peanuts (P<.001).¹

Because the study focused on infants with severe eczema and/or egg allergies who are at very high risk of developing a wide range of allergies, it’s not yet completely clear how these findings should be applied to general pediatric practice. Ongoing studies should help clarify this point, and consensus guidelines are forthcoming.

More: Misdiagnosis can happen with food allergy panel test

When it comes to detecting food allergies, physicians to date have been hamstrung by tests that yield accuracy rates in the range of 50% and many false-positive results. Newer approaches include component testing (or component-resolved diagnostics), which, for peanut allergy, significantly improves diagnostic accuracy above that of the usual blood or skin tests. Component testing won’t replace these tests, but it provides a welcome supplement.

For food allergy treatment, new immunotherapeutic approaches mirror that of allergy shots for airborne or other allergens. The general idea is that by gradually exposing patients to problematic allergens, you may be able to build some tolerance. For example, oral immunotherapy involves patients eating foods to which they are allergic in extraordinarily small amounts which are gradually increased over 6 to 12 months. Over that time, a majority of children can develop a significantly increased tolerance to that food. In addition, the epicutaneous or “patch” approach currently under investigation for peanut allergy is also showing encouraging results. This project is scheduled to enter US Food and Drug Administration (FDA) phase 3 testing in 2015’s fourth quarter.

Reference

1. Du Toit G, Roberts G, Sayre PH, et al; LEAP Study Team. Randomized trial of peanut consumption in infants at risk for peanut allergy. N Engl J Med. 2015;372(9):803–813.

Robert A Wood, MD, FAAP, is professor of pediatrics and international health, and director, Pediatric Allergy and Immunology, Johns Hopkins University School of Medicine, Baltimore, Maryland.

NEXT: Commentary and a look at other food allergies

Commentary

The New England Journal of Medicine article showing that early introduction of small amounts of peanuts decreased by more than 5-fold the onset of peanut allergy in children followed up to almost age 5 years made a big splash in the pediatric community, particularly among those interested in immune-mediated diseases.

Now, the real deal starts. The American Academy of Pediatrics sooner or later will take an official position indicating how these findings should be incorporated into clinical practice. And we will have an answer to the question we have right now: Can this approach be generalized to kids with peanut allergy, or only the ones at highest risk for developing peanut allergy? Only time will tell.

Next: Is it peanut avoidance the best practice?

The other question is, what about other food allergies? Can we eventually extrapolate the findings regarding peanut allergy to other food allergens like cow’s milk, wheat, and other problematic dietary components, so that we can reeducate the dietary systems of infants who are genetically prone to develop these food allergies?

I use the term reeducate because the issue we are struggling with as immunologists is how foods that should be good for us can become harmful for a subset of individuals. Why has the incidence of food allergy exploded in the last 2 or 3 decades to epidemic proportions?

It’s not that we as human beings are changing genetically. The timeframe is too short to breed genetic mutations that would render us more susceptible to this problem. It’s probably that we are changing the environment too quickly for us to adapt to it.

Genetically speaking, the immune system has been built to defend us against enemies, not attack us. Under normal circumstances, when the immune system encounters food allergens, it should not do anything to us. It should tolerate these allergens. The question is, how can we reprogram the immune system not to go after these proteins by releasing histamine from mast cells and producing immunoglobulin E, thereby creating situations that lead to clinical outcomes like peanut allergies?

A word of caution. We’ve made a tremendous step toward a better understanding of how eventually to stop, or at least slow down, the food-allergy epidemic. But we are far from having a definitive answer regarding whether early, gradual exposure is effective, and effective for everyone who suffers from food allergies. We are currently at a work-in-progress stage. If pediatricians begin to embrace this approach as the standard of care, then we will see if it’s going to work on a broader scale or not.

Alessio Fasano, MD, is director, Division of Pediatric Gastroenterology and Nutrition, Massachusetts General Hospital for Children, Boston, Massachusetts.