Therapy for milk allergy offers hope, and caution
Large study shows benefits of gradual introduction to dairy, but protection waned for some patients in smaller studies
SAN ANTONIO — For people with a dairy allergy, gulping down a glass of milk is unthinkable. But many patients came away with that ability after a months-long program of exposure to increasing amounts of milk, researchers from Israel reported February 24 at a meeting of the American Academy of Asthma, Allergy and Immunology.
But other data released at the conference raise questions about the long-term sustainability of such treatment. Researchers at Johns Hopkins University report that many children have seen their allergy return several years after completing a similar regimen of what allergists call oral immunotherapy.
“I think they’re not as protected as we were led to believe,” says Robert Wood, an allergist at Johns Hopkins who reported follow-up data on 32 patients.
In the study in Israel, 280 people ages 4 to 27 began the regimen by consuming less than 1 milligram of milk protein, followed by increases every 15 to 30 minutes during the day until they consumed up to 120 milligrams. The patients were treated in a clinic for four days. People who developed allergic symptoms, such as throat swelling or abdominal pain, returned to a dose that they could tolerate, says study coauthor Michael Levy, an allergist at Assaf Harofeh Medical Center in Zerifin.
Participants then went home and twice a day consumed the highest dose of milk that they could tolerate in the clinic, returning to the clinic monthly to receive escalating doses. Of the 280 patients treated for at least seven months, 160 were able to consume 7,200 milligrams of milk protein, the equivalent of about one-fourth of a liter of milk, without a reaction by the end of the study. “They are eating freely all dairy foods,” Levy said.
Another 66 patients who finished the treatment can handle smaller amounts of milk regularly, and 15 are still working through gradual escalations. Being able to consume even modest amounts is valuable, Levy said, because it reduces the likelihood of an accidental allergic reaction. But 39 people in the study simply couldn’t tolerate milk and had to abandon treatment, suggesting there is a group that doesn’t benefit from the approach.
In the other analysis, which included patients from two previous smaller studies, Wood reported that only eight of 32 children who received treatment three to five years earlier at Johns Hopkins were still free of symptoms when ingesting milk. Five can’t touch it, and the rest have occasional to frequent reactions to milk, Wood said at a press briefing February 25. Most had originally completed treatment without symptoms.
Brian Vickery, a pediatric allergist at the University of North Carolina at Chapel Hill who wasn’t part of either analysis, said the Israeli approach is similar, but not identical, to other oral immunotherapy treatments being tried for milk allergy. And while the experimental treatment yielded good responses in many people at an early stage of follow-up, he says, the Johns Hopkins findings suggest that real-life behavior could make or break the therapy.
Wood noted that some children may have neglected to keep up with consuming at least a little milk each day, and as a result, lost the protection. Vickery said such daily contact might be simultaneously the most essential and difficult aspects of the therapy, since kids often get anxious or even fearful about eating food they have learned to avoid.
No oral immunotherapy has been approved for any food allergy by the U.S. Food and Drug Administration.