Putting the brakes on food allergies could do a body good

This photo contains at least three food allergens. Can you find them? (Photo: bensonkua/Flickr)

About 3 million children in the U.S. have some form of food allergy, ranging in severity from mild to life-threatening. The number of children diagnosed with food allergies is rising: at Children’s alone, the percentage of new patients with food allergies jumped from 14 in 1998 to 46 in 2005.

The numbers don’t really describe what it means for a child to have an allergy to milk or other foods. At age 1, Brett Nasuti was diagnosed with allergies to 15 foods, including milk, nuts, and eggs. “When I was little, I got hives in the shape of my mom’s lips when she kissed me after drinking coffee with just a little milk in it,” he says.

The classic way of addressing a food allergy is through a vigilant avoidance of the food(s) that can trigger an anaphylactic reaction and prompt treatment of reactions when they do occur. That approach got a boost last year from the Massachusetts legislature, which passed a law requiring restaurants to educate their workers and managers about food allergies and print warnings in their menus reminding diners to tell their server about any food allergies in their party.

But with the still-unexplained rise in food allergies, which is placing ever-greater societal pressures on families and schools as well, we urgently need a shift in thinking from avoid-and-react to something more proactive. Maybe, as with seasonal or hay fever allergies, the answer to food allergies really is carefully controlled exposure – teaching the body to be tolerant of allergens, instead of going haywire.

Brett is helping us chart the path to this new way of thinking.

Brett Nasuti in the Children's Clinical & Translational Study Unit during the milk desensitization study.

Two years ago, at age 11, he entered a pioneering clinical study aimed at treating milk allergy – the most common food allergy, affecting 2.5 percent of children under age three – by carefully and gradually increasing his milk intake in tandem with use of an allergy drug called omalizumab (marketed by Genentech under the name Xolair®). The idea was to avoid immunologic overreactions by stifling IgE (the antibody responsible for activating responses to allergens and, interestingly, parasites). This would allow his body to build up tolerance to milk and overcome his allergy. Children’s allergist Lynda Schneider, who led the study with immunologist Dale Umetsu and colleagues at Stanford University, explains:

“This is the first study to use omalizumab in combination with oral desensitization,” says Umetsu. “Using omalizumab allowed us to escalate their milk intake very rapidly compared to other desensitization protocols, and still limit allergic reactions.”

Recently, Umetsu and Schneider presented the results of their study at the annual meeting of the American Academy of Allergy, Asthma, and Immunology: Of the 11 children who took part in the study, nine successfully completed it – including Brett. The kids still have at least eight to 12 ounces of dairy each day now to maintain their tolerance. Brett even had a pizza party.

“We decided to start with milk because treating it successfully could change a child’s lifestyle for the better,” Umetsu noted. “These children had significant milk allergy, and were unlikely to outgrow it without some type of treatment.”

The results have shown enough promise that Umetsu and Schneider are launching a new study that will try the same technique for desensitizing kids with peanut allergy, rates of which doubled between 1997 and 2002. “We believe this process could be applied to any food,” Umetsu concluded. “Hopefully, in the near future, we can tell patients, ‘We can cure your food allergies.’ It’s a totally new era.”

But how can we get to the root causes of the rapid rise in food and other allergies, like asthma? This is something that researchers like Umetsu and Schneider desperately want to understand. It may have something to do with genes, with the overall cleanliness of our culture, with the age when a child first experiences a new food, with diet…the answers are there, but at the moment remain elusive.