Can allergy immunotherapy desensitize patients allergic to wheat?
A recent clinical trial studied the effects of wheat oral immunotherapy in allergic children.
Bread wheat is among the most widespread crops in the world thanks to its high yields and the capability to grow in different climates. In addition to its properties as a crop, wheat is flavorful, nutritious, and provides a base for foods such as pasta, bread and pizza, and for drinks such as beer.
Despite its beneficial properties, wheat can cause allergic reactions in some people. When we eat, our digestive system breaks down food into its basic components. In people with a genetic predisposition, the protein component of wheat can trigger an allergic reaction. Allergies to this cereal are more common in children than in adults. The majority of patients outgrow this allergy by the time they turn 16 years old, which explains the lower occurrence in adults.
Symptoms of a wheat allergy can include hives, asthma, abdominal pain, vomiting, hay fever and dermatitis. Anaphylaxis is a life-threatening reaction and the most severe potential outcome of a wheat allergy. These episodes usually happen within seconds to minutes after exposure to the allergen, but can also happen with a delay of several hours. Symptoms of anaphylaxis include hives, difficulty breathing, vomiting and fainting. Reactions to wheat are not limited to its ingestion. A reaction can even occur from inhalation, causing asthma and hay fever in sensitive people that are constantly exposed to wheat products.
Avoidance is currently the main prevention method for wheat allergies
Currently, treating the symptoms and avoiding exposure to wheat are the main ways to manage this allergy. Allergy immunotherapy is a new treatment that is showing promising results in clinical studies. This approach aims at lowering the sensitivity of a patient to a certain food. Slowly increasing exposure to the allergen can achieve this goal, ultimately reducing the severity of the symptoms. A recent clinical trial looked at the effects of wheat oral immunotherapy in a group of allergic patients. The results were published in the Journal of Allergy and Clinical Immunology.
The main objectives of this study were to evaluate the efficacy and safety of vital wheat gluten oral immunotherapy. Vital wheat gluten is a derivate of wheat flour and is rich in wheat protein. The high protein content of vital wheat gluten allowed the ingestion of the desired amount of wheat protein without requiring the participants to eat an excessive amount of food.
The researchers randomly assigned 46 participants between the ages of four and 30 to two groups. One group was treated with oral immunotherapy (OIT group), while the other one was administered a placebo and served as a control for comparison. Participants in the OIT group received increasing doses of wheat protein over a one-year period, followed by a maintenance period of another year. Efficacy of the treatment was tested at the one-year mark and after the second year by monitoring the sensitivity of patients to wheat.
Wheat oral immunotherapy successfully desensitized allergic patients
The results showed that sensitivity to wheat decreased in approximately half (52.2%) of participants in the OIT group after the first year of treatment. These individuals were able to eat a cumulative amount of wheat products equivalent to one to two slices of bread without symptoms. In contrast, participants in the placebo group did not show any improvement. After the second year of allergy immunotherapy, 30% of treated patients in the OIT group were no longer sensitive to wheat as they managed to eat the equivalent of a typical serving of wheat without adverse reactions.
Researchers tested allergy levels in the participants once again approximately two months after stopping treatment and found that only 13% were still not sensitive to wheat protein. In terms of safety, the most commonly experienced side effects during the first year of OIT treatment were respiratory and gastrointestinal symptoms, with only a small fraction being severe. Even though the frequency of symptoms decreased during the second year of therapy, 24% of the participants withdrew because of dosing reactions.
One limitation of the study is the small number of participants. A small group of patients might not be a good representative of the population affected by wheat allergies. Moreover, the patients enrolled in this clinical trial were highly allergic to wheat with severe reactions. Enrolling patients with milder allergies might have improved both the efficacy and the safety of this study.
Adjustments of dose and treatment duration are the next steps to optimize wheat oral immunotherapy
In conclusion, this study evaluated the safety and efficacy of oral immunotherapy for wheat allergies. Eating increasing doses of wheat protein over a one-year period reduced the sensitivity of a large portion of patients. After another year of treatment, 30% of the treated participants could eat the equivalent of a portion of wheat products without symptoms.
Despite the positive results, the effects of this therapy did not last as long as those obtained with egg immunotherapy in another study. At the same time, this research work provides the basis for further improvement of the therapy, likely with adjustments of dosage and length of treatment.
Written by Raffaele Camasta, PhD
References:
- Nowak-Węgrzyn, A., Wood, R. A., Nadeau, K. C., Pongracic, J. A., Henning, A. K., Lindblad, R. W., Beyer, K., & Sampson, H. A. (2018). Multicenter, randomized, double-blind, placebo-controlled clinical trial of vital wheat gluten oral immunotherapy. Journal of Allergy and Clinical Immunology.
- Cianferoni, A. (2016). Wheat allergy: diagnosis and management. Journal of Asthma and Allergy, 9, 13–25.
- Mount Sinai researchers find wheat oral immunotherapy to be therapeutic for allergic patients. https://www.eurekalert.org/pub_releases/2018-10/tmsh-ms103018.php
- Baiu, I., & Melendez, E. (2018). Anaphylaxis in Children. JAMA, 319(9), 943.
