Omalizumab Therapy Is Associated with Reduced Circulating Basophil Populations in Asthmatic Children
Tuesday, March 4, 2014
Exhibit Hall B (Convention Center)
David A. Hill, MD, PhD, Mark Siracusa, PhD, Kathryn Ruymann, Elia Tait Wojno, PhD, David Artis, PhD, Jonathan M. Spergel, MD PhD FAAAAI
Rationale: Basophils have been implicated in promoting the early development of TH2 cell responses in some murine models of TH2 cytokine-associated inflammation. However, the specific role of basophils in allergic asthma remains an active area of research. Recent studies in animal models and human subjects suggest that IgE may regulate the homeostasis of human basophil populations. Here, we examine basophil populations in children with severe asthma before and during therapy with the IgE directed monoclonal antibody omalizumab. Methods: Subjects were selected based on age between 5 and 18 years, body weight and IgE level compatible with the omalizumab dosing table, and severe asthma. Asthma symptoms assessments were administered during therapy. Peripheral blood samples were obtained before and during therapy and basophil frequencies and numbers were monitored using flow cytometric techniques. Results: Omalizumab therapy was associated with a significant reduction in circulating basophil frequencies and numbers (p<0.05, Wilcoxon Signed Rank Test), a finding that correlated with improved clinical outcomes. Conclusions: The observation that circulating basophils are reduced following omalizumab therapy supports a mechanistic link between IgE levels and circulating basophil populations and may provide new insights into one mechanism by which this drug improves asthma symptoms.