A New Technique Helps Track Down the Specific Culprits in Food Allergies

For many who suffer from food allergies, pinpointing the exact cause of the reaction can be difficult. Food proteins are typically the culprits. Though training the body's immune system to respond to certain proteins found in foods can be helpful, it may also require extensive testing that won't always pick up on rarer allergens. However, a new study published in Analytical Chemistry shows that a highly-sensitive method could help track culprit proteins and low concentrations that might normally be missed.

Many food allergies are becoming more widespread throughout the Western world. Food allergies, similar to other allergies, happen when the immune system produces antibodies to destroy "enemy" molecules, such as those from bacteria or viruses.
A particularly common allergy among children is known as the cow milk allergy, which prevents many from breastfeeding and drinking milk. However, some outgrow the problem by around the age of six. For this and other milk allergies, doctors test for antibodies called "IgE." Yet this alone does not tell them which one of the numerous proteins in milk--and other foods--causes the allergic response.

For the study, researchers developed a highly-sensitive method that incorporates IgEs to help determine the specific protein that induces the allergy with help from the technique immunoaffinity capillary electrophoresis (IACE).

First, researchers isolate IgE antibodies from the patient's blood through interaction with magnetic beads that are coated with a different type of antibody. Next, the "bead" antibodies work to recognize and bind the patient's IgE antibodies, which take place inside a long and narrow tube that's only 50 micrometers in diameter, known as a "capillary." These beads are flushed out of the capillary and attached to magnetic beads through a process known as ‘crosslinking,' which helps keep them detached. The beads with the patients IgE were then placed inside the capillary again.

As milk is injected into the capillary, the proteins pass over the patient's IgE antibodies and cause the allergies to get caught up by them while others exit on the inside. The beads are then washed with a strong chemical that causes the allergy-inducing protein to dissociate from the patient's IgE antibodies. This "culprit" protein is then identified using mass spectrometry, which analyzes the compounds mass and electrical charge.

With a more personalized approach to identify exact proteins caused by food allergies, researchers can work to provide more effective treatments for food allergies in the future.