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.