Biomarker for severe food allergy could help individualize allergy care

How could individualized medicine be used to improve the treatment of children with food allergies? That’s the question Dr. Julia Upton set out to answer when she began studying the possibility of a biomarker, or a measurable piece of evidence in the blood, that might indicate the potential risk of a child having a severe anaphylactic reaction to a food allergy. 

Upton’s research on this topic was published in Allergy: European Journal of Allergy and Clinical Immunology. In the study, the research team examined the blood of 46 children taken to the Emergency Department at The Hospital for Sick Children (SickKids) with anaphylaxis as the result of a severe food allergy, and 36 of those children again in a follow-up appointment at least four weeks later. The researchers found that the patients who had a low level of an enzyme called platelet-activating factor acetylhydrolase, or PAF-AH, were at a greater risk of a severe anaphylactic reaction, compared to those with a higher level of the enzyme.  

The data from the follow-up appointments also showed that the enzyme levels seen in the original blood test remained low after the anaphylaxis event was over. This is to say that some people have a low level of this enzyme, which puts them at risk of severe reactions if they happen to have a food allergy. While this enzyme isn’t the cause of food allergies, the data could be used to potentially predict which people with an allergy may be at risk of a severe reaction.  

“Most children with food allergies are assumed to be at risk of a severe reaction, and this can be incredibly disruptive to a patient or family's quality of life because of the fear or anxiety that come with potentially life-threatening food allergies,” says Upton, Project Investigator at SickKids Research Institute and Co-Director of the SickKids Food Allergy and Anaphylaxis Program. “The findings of this study could help outline the spectrum of risk.” 

It’s Upton’s hope that these findings will one day be used to not only help predict who will have severe anaphylaxis but will also help predict who is at a low risk of severe anaphylaxis.  

Upton says the goal of the Food Allergy and Anaphylaxis program at SickKids is to take what she describes as the “fear out of food.” Part of the program's efforts are in supporting research aimed at understanding the mechanisms behind food allergies and anaphylaxis.  

“There are multiple ways we can help take the fear out of food due to allergies, including improving diagnosis, treatment and prediction of severity. If we know why these things happen, there’s a possibility that patients can have a better understanding of their risk factors, helping them be less afraid of the food they consume,” says Upton. 

If a blood test could tell patients where they measure on the risk-scale for severe anaphylaxis, she says, it could allow doctors to potentially develop individualized care plans based on a person’s individual risk factors, rather than having one standardized approach for everyone with food allergies. The research is an example of SickKids’ vision for Precision Child Health, a movement that will shift medicine from a one-size-fits-all approach to individualized care for every patient.   

“Being able to better understand who’s at the highest risk and who’s at the lowest of a severe allergic reaction could really help patients and families as well as physicians better manage a food allergy and help reduce everyday stress and fear," says Upton.