An estimated 4.2 million children worldwide suffer from a peanut allergy. For these patients, even the slightest peanut ingredients can have fatal consequences. Allergic reaction is essentially the binding of allergens to antibodies called immunoglobulin E (IgE) on the surface of immune cells, which in turn leads to complex chain reactions that can lead to rashes to anaphylactic shock and so on.
Now, in a new study published in the journal PNAS, researchers used an allergen-specific inhibitor that effectively prevented peanut allergens from binding to IgE to inhibit allergic reactions to peanuts. The success of this study is exciting. “Because it opens the door to new allergy treatments,” the authors said, “We now have the first functional example of selective IgE inhibition of food allergens that we have never had before.”
In the early stages of anaphylaxis, IgE binds to allergen proteins on the surface of immune cells called mast cells, releasing histamine and other particles, which is the first and most critical step in a patient’s allergic reaction. There are currently no drugs that can stop the process. Inhibitors targeting only IgE can lead to widespread immunosuppression, which has been shown to lead to an increase in parasitic infections and even cancer. Therefore, the authors hope to develop an inhibitor designed to specifically inhibit the binding of IgE to allergen proteins without interfering with any other immune system function.
To achieve their goal, the authors and others used nanoparticles called “nano-allergens” to screen and identify key binding sites on peanut proteins recognized by patients’ IgE antibodies. Based on the above results, the authors synthesized a special inhibitor, called covalent heterobivalent inhibitor (cHBI), to prevent IgE from binding to peanut protein. In a study of 16 patients with severe peanut allergy, cHBI successfully inhibited allergic reactions in up to 90 percent of all samples.
This study provides a convincing case for the further development and evaluation of cHBI as a feasible strategy for the treatment of peanut allergy.
Deak, P. E., Kim, B., Qayum, A. A., Shin, J., Vitalpur, G., Kloepfer, K. M., … & Kaplan, M. H. (2019). Designer covalent heterobivalent inhibitors prevent IgE-dependent responses to peanut allergen. Proceedings of the National Academy of Sciences, 201820417.