Monitoring and stopping Hymenoptera venom immunotherapy: Contribution of IgE blocking activity

Background: Hymenoptera venom allergy is a public health issue and has an undeniable impact on quality of life. Allergen immunotherapy (AIT) has shown long-term efficacy in this severe and potentially lethal allergy. However, no biomarker can predict the effectiveness of this treatment.

Objectives: We evaluated the contribution of IgE blocking activity, a functional biomarker carried out in our center using flow cytometry, to predict the efficacy of AIT.

Methods: This retrospective study from 1985 to 2022 describes in detail the demographic, clinical, and biological characteristics of patients who benefited from AIT with Hymenoptera venom at the University Hospital of Limoges. The outcome measure used was the presence of anaphylactic reaction (grade I to IV according to Ring and Messmer) in case of a new sting after discontinuation of AIT.

Results: Our study, mainly composed of patients allergic to Vespula wasp venom, did not emphasize the interest of IgE blocking activity in the prediction of a relapse after a new sting. However, this inhibition showed a significant correlation with the amount of IgG₄ antibodies.

Conclusion: There is no biomarker that can help make the decision of stopping AIT. However, low levels of IgE blocking activity may suggest a likelihood of relapse. Serum IgG₄, in correlation with IgE blocking activity, could be useful for monitoring treatment response. Additional studies are necessary to gain a thorough understanding of the composition of inhibitory antibodies.