Gene Expression During Anaphylaxis Differs Depending on Symptoms
Anaphylaxis reactions presenting with gut and skin symptoms alone do not differ from more mild reactions, in contrast to reactions involving respiratory and/or laryngeal symptoms, according to research presented at 2019 AAAAI Annual Meeting
San Francisco, CA – Anaphylaxis, a potentially life-threatening allergic reaction, is categorized by a number of symptoms, but only those with respiratory or laryngeal involvement result in changes in gene expression.
The study, a collaboration between Imperial College London, Children's Hospital of Philadelphia and Penn Genomic Analysis Core Facility (funded by the UK Medical Research Council and End Allergies Together), was presented for the first time at the 2019 Annual Meeting of the American Academy of Allergy, Asthma & Immunology. Whole blood transcriptomic analysis was performed on blood samples obtained prior to and during double-blind placebo-controlled food challenges in 94 peanut-allergic children and adults, with 62% having anaphylaxis.
Significant changes in gene expression were seen two hours following anaphylaxis, but these were not apparent at earlier timepoints or prior to challenge. “Based on this,” said co-author Jonathan M. Spergel MD, PhD, FAAAAI, “it appears acute reactions are due to preformed mediators, which are released quickly following cell stimulation. This would imply changes in gene expression aren’t responsible for acute allergic reactions.”
Interestingly, anaphylaxis reactions involving only the gut and skin had the same transcriptomic signature as non-anaphylaxis reactions to peanut. Such reactions, when triggered by food, are not considered to be anaphylaxis in the UK and Australia. In contrast, reactions involving laryngeal and/or lower respiratory symptoms were associated with altered expression of 22 genes. This suggests that anaphylaxis reactions involving laryngeal and lower respiratory symptoms may have a different underlying pathophysiology.
“This is the first study assessing the relationship between gene expression and reaction severity in peanut-allergic individuals,” said co-author Paul J. Turner, FRACP, PhD. “It implies that reactions involving the airways induce a different response compared to more common reactions which only involve the skin and gut.”
Moving forward, future research will investigate why some allergic individuals have far more severe anaphylaxis reactions than others. According to Dr. Turner, “our biggest gap in managing patients with food allergy is our inability to predict those at greatest risk of severe reactions. This research gets us one step closer to addressing this.”
Visit aaaai.org to learn more about anaphylaxis. Research presented at the AAAAI Annual Meeting, February 22-25 in San Francisco, California, is published in an online supplement to The Journal of Allergy and Clinical Immunology.
The American Academy of Allergy, Asthma & Immunology (AAAAI) represents allergists, asthma specialists, clinical immunologists, allied health professionals and others with a special interest in the research and treatment of allergic and immunologic diseases. Established in 1943, the AAAAI has nearly 7,000 members in the United States, Canada and 72 other countries. The AAAAI’s Find an Allergist/Immunologist service is a trusted resource to help you find a specialist close to home.