Understanding Food Anaphylaxis
The Risks of Food Allergies
While some individuals can enjoy their favorite foods without worry, others face the threat of food anaphylaxis, a severe allergic reaction that can be life-threatening. Recognizing how your body reacts to food allergens is crucial, as it could mean the difference between using Benadryl for hives and carrying an EpiPen for anaphylaxis. Currently, many parents of children with allergies and individuals who have recently developed food reactions often adopt a ‘wait and see’ approach regarding the severity of their food intake.
A New Blood Test for Food Allergy Risk
Research Breakthrough
A recent study published in The Journal of Allergy & Clinical Immunology aims to change the landscape of food allergy diagnosis. Researchers at Ann and Robert H. Lurie Children’s Hospital discovered that individuals with elevated levels of an enzyme known as α-tryptase, which is encoded by the TPSAB1 gene, are at a higher risk of experiencing severe allergic reactions to food. The study shows that a simple PCR test on blood or saliva can measure α-tryptase levels, potentially leading to a diagnostic test that identifies individuals at high risk for severe food allergies. Currently, no such test exists, leaving many unaware of their anaphylaxis risk.
Insights from the Research
Dr. Abigail Lang, the lead author of the study, shared with Healio, “As clinicians, we are often asked by patients and families if a food allergy is mild or severe. Concerns about reaction severity significantly impact the quality of life for patients with food allergies.”
The Science Behind Tryptase and Allergic Reactions
Mast Cells and Their Role
Mast cells, specialized immune cells, produce tryptase enzymes in two forms: α-tryptase, encoded by the TPSAB1 gene, and β-tryptase, encoded by the TPSB2 gene. Mast cells primarily function to combat invading pathogens; however, they can mistakenly attack food particles, leading to anaphylaxis. During this severe reaction, mast cells release both α-tryptase and β-tryptase into the bloodstream, with variations in individual genetic makeup influencing the levels produced.
Link Between TPSAB1 and Allergic Reactions
Research Findings
Previous studies have suggested a correlation between an increase in TPSAB1 copy number and severe allergic reactions to insect stings (Hymenoptera venom allergy). In this study, researchers assessed 119 individuals diagnosed with food allergies to determine the number of copies of the α-tryptase gene present. The findings revealed that individuals with a higher number of α-tryptase copies experienced more frequent and severe allergic reactions compared to those without this genetic marker. Dr. Lang noted, “The presence of α-tryptase in subjects is correlated with a higher prevalence of anaphylaxis or severe reaction to food than in subjects without any α-tryptase.”
References
1. Lang, A., Kubala, S., Grieco, M. C., Mateja, A., Pongracic, J., Liu, Y., Frischmeyer-Guerrerio, P. A., Kumar, R., & Lyons, J. J. (2023). Severe food allergy reactions are associated with α-tryptase. The Journal of Allergy and Clinical Immunology, 152(4), 933–939. https://doi.org/10.1016/j.jaci.2023.07.014.
2. Richard Gawel. (2023, August 18). Alpha-tryptase may indicate potential for severe food allergy reactions. Healio. https://www.healio.com/news/allergy-asthma/20230818/alphatryptase-may-indicate-potential-for-severe-food-allergy-reactions.
3. Sprinzl, B., Greiner, G., Uyanik, G., Arock, M., Haferlach, T., Sperr, W. R., Valent, P., & Hoermann, G. (2021). Genetic Regulation of Tryptase Production and Clinical Impact: Hereditary Alpha Tryptasemia, Mastocytosis and Beyond. International Journal of Molecular Sciences, 22(5), 2458. https://doi.org/10.3390/ijms22052458.
4. Ruëff, F., Przybilla, B., Biló, M. B., Müller, U., Scheipl, F., Aberer, W., Birnbaum, J., Bodzenta-Lukaszyk, A., Bonifazi, F., Bucher, C., Campi, P., Darsow, U., Egger, C., Haeberli, G., Hawranek, T., Körner, M., Kucharewicz, I., Küchenhoff, H., Lang, R., Quercia, O., … Wüthrich, B. (2009). Predictors of severe systemic anaphylactic reactions in patients with Hymenoptera venom allergy: importance of baseline serum tryptase—a study of the European Academy of Allergology and Clinical Immunology Interest Group on Insect Venom Hypersensitivity. The Journal of Allergy and Clinical Immunology, 124(5), 1047–1054. https://doi.org/10.1016/j.jaci.2009.08.027.