Oral immunotherapy promising for egg allergies, SLIT for milk allergies

Mar 1 2010

EASING EGG ALLERGIES WITH EGGS 

Oral immunotherapy study at Hopkins Children's shows it works 

Children with egg allergies who consume increasingly higher doses of egg protein - the very nutrient they react to - appear to gradually overcome their allergies, tolerating eggs better over time and with milder symptoms, according to research conducted at Johns Hopkins Children's Center and elsewhere.

The findings from a multi-center trial are to be presented at the annual meeting of the American Academy of Allergy, Asthma & Immunology Feb. 26 through March 2.

Previous research at Hopkins Children's showed that the same approach, known as oral immunotherapy, can be used successfully to treat children with milk allergies. Some of the children in the milk allergy study overcame their condition completely, and many experienced less severe allergic symptoms as a result of the therapy.

Now, researchers are reporting similarly encouraging results in children with egg allergies.

"Just as we saw in our patients with milk allergies before, oral immunotherapy for children with egg allergies works in the same way by slowly retraining the immune system to tolerate the allergens that caused allergic reactions," says study investigator Robert Wood, M.D., director of Allergy & Immunology at Hopkins Children's.

Researchers caution that confirming these early results requires long-term monitoring of the current patients and enrolling more children in the ongoing trials. They also caution that oral immunotherapy should be implemented only by a trained pediatric allergist.

In the 11-month study of 45 children ages 5 to 18, researchers gave 40 patients increasingly higher doses of egg whites during multiple food challenges conducted in a clinic and under a doctor's supervision, while 15 children received placebo, "dummy" food that looks like egg whites but contains no egg protein. All children received higher and higher doses of either placebo or actual egg protein in the course of the 11 months.

At the end of the study, during a final food challenge, more than half of the children who had been consuming eggs (21 out of 40) could tolerate 5 grams of eggs without having an allergic reaction. None of the children who received placebo were able to tolerate eggs during the final food challenge.

When symptoms did occur, investigators say, they were mild to moderate and involved mostly itching and swelling of the mouth and throat.

Children who consumed eggs also had lower blood levels of IgE antibodies - immune markers that rise during an allergic reaction - and a significant drop in the levels of egg-specific basophils, a type of while blood cell that multiplies during an allergic reaction.

Food allergies have been steadily rising in the last decade and are becoming harder to outgrow, research shows. An estimated 2 percent to 3 percent of U.S. children have egg allergies.

"MILK DROPS" UNDER THE TONGUE APPEAR TO TREAT MILK ALLERGIES

Placing small amounts of milk protein under the tongues of children who are allergic to milk can help them overcome their allergies, according to the findings of a small study at Johns Hopkins Children's Center and Duke University.

The findings will be presented on Sunday, Feb. 28, at the annual meeting of the American Academy of Allergy, Asthma & Immunology .

The approach, known as SLIT (sublingual immune therapy), involves giving children small but increasingly higher doses of the food they are allergic to until their immune systems "learn" to tolerate the food without triggering an allergic reaction or triggering only mild symptoms. Previous research from Hopkins Children's showed that a similar approach known as oral immunotherapy can successfully treat children with milk allergies. Unlike SLIT, oral immunotherapy involves consuming milk protein rather than merely placing it under the tongue.

The current study suggests that both approaches could be effective in treating milk allergies in most patients, authors say, but that oral immunotherapy appears to be slightly more effective than SLIT. The investigators caution that the results are preliminary and that the two approaches must be compared in larger groups before their equal efficacy can be confirmed.

While both approaches work by exposing the patient to progressively higher doses of the allergenic food, SLIT is done with lower doses-and therefore with lower risk for a severe allergic reaction. Researchers caution that both therapies can lead to violent allergic reactions in some patients, and should be always done under a doctor's supervision.

"We are very excited to see that both approaches can achieve significant improvement in children with milk allergies, but we continue to see slightly better tolerance in children on oral immunotherapy," says lead investigator Robert Wood, M.D., director of Allergy & Immunology at Hopkins Children's. "Nonetheless, SLIT emerges as a new, if slightly less powerful, weapon in our arsenal."

In the study, all 30 children ages 6 to 17 were treated with milk drops under the tongue (SLIT) for several weeks until they built up their tolerance. Once minimum tolerance was achieved, the children were divided into two groups. Ten children continued their SLIT treatment while the other 20 consumed milk powder by mouth (OIT). After three months of treatment with increasingly higher doses of milk protein, all children underwent a food challenge, which involved drinking milk under a doctor's supervision.

All children in the "by mouth" group were able to drink on average seven times more milk without an allergic reaction or with mild symptoms compared to their baseline milk challenge before the treatment. Nine of the 10 children treated with milk drops under the tongue, were able to do so.

Children in both groups experienced allergic symptoms equally often during the treatment. In the "under the tongue" group, 33 percent of the 3,619 doses of milk administered caused symptoms, compared to 35 percent of the 3,773 doses in the "by mouth" group. Most symptoms were mild, with the most common ones being mouth and throat itching and irritation. Abdominal and respiratory symptoms occurred very infrequently, the researchers report.