Basophil FceRI expression—A management tool in anti‐IgE treatment of allergic asthma

Background Immune‐based therapy targeting immunoglobulin E (IgE), anti‐IgE treatment, has emerged as an adjunct treatment for children with severe allergic asthma. After start of anti‐IgE treatment, an effect of the treatment cannot be monitored by Total‐IgE, because current methods measure both bound and free IgE molecules. Basophil activation test may be very useful for monitoring anti‐IgE treatment efficacy. The objective of this paper is to evaluate if basophil activation test is applicable in regulating the anti‐IgE treatment. Methods A case series of 20 children with IgE‐mediated severe allergic asthma were treated according to guidelines with anti‐IgE (Omalizumab). Blood samples were drawn for total IgE, specific IgE, number of IgE receptors (FcεRI) and basophil sensitivity were measured at baseline before anti‐IgE treatment and 4 months after initiation of anti‐IgE treatment. Results A total of 19 out of 20 children had statistically significant and clinically relevant effects of anti‐IgE treatment on symptom score, lung function and medication. All 20 children had a significant reduction in basophil allergen sensitivity and the number of IgE receptors (FcεRI) on blood basophils. Anti‐IgE treatment was found to be well controlled by measuring basophil allergen sensitivity and FceRI density on blood basophils. Conclusion This cohort study demonstrates a promising method, measuring basophil allergen sensitivity and in particular blood basophil FceRI density, concerning the monitoring of anti‐IgE treatment in different clinical situations. There are no randomized controlled trials evaluating this method in clinical settings.