Influence of effective omalizumab treatment on eosinophils in allergic asthma with comorbidities

Abstract Background Omalizumab is an effective anti-immunoglobulin E(IgE) treatment for allergic asthma. Eosinophil plays a critical role in the pathogenesis of allergic airway inflammation. This study aimed to evaluate the efficacy of omalizumab on comorbidities of allergic asthma and explore influence of omalizumab on circulating eosinophils. Methods Allergic asthmatics enrolled in the study were treated with omalizumab for at least 16 weeks and exhibited a good or excellent response according to the global evaluation of treatment effectiveness (GETE) assessed by each patient and specialist physician. Asthma Control Test (ACT) and Mini Asthma Quality of Life Questionnaire (Mini-AQLQ) for asthma, Mini Rhino-conjunctivitis Quality of Life Questionnaire (Mini-RQLQ) for allergic rhinitis (AR), Visual Analogue Scale (VAS) for systemic allergic symptoms, Leicester Cough Questionnaire (LCQ) for cough variant asthma (CVA) and Self-rating Anxiety Scale (SAS) were collected at baseline and week 16. For eosinophil functional evaluation, peripheral eosinophils were separated and examined the expression of human leukocyte antigen DR (HLA-DR) and co-stimulatory molecules CD80, CD86 and CD40 by Flow Cytometry and serum to measure the concentration of eotaxin-1 before and after 16 weeks of omalizumab treatment. Results Totally 32 allergic asthma patients who responded positively to omalizumab treatment were included. Omalizumab increased LCQ (3.03, p = 0.009), reduced mini-RQLQ (-8.5, p = 0.047), and SAS (-5.08, p = 0.04) in CVA patients, or allergic asthmatics complicating AR or anxiety, respectively. Omalizumab responders showed a significant decline in expression of co-stimulatory molecules CD40, CD80, and CD86 on peripheral eosinophils and in serum eotaxin-1 concentration after treatment. Negative correlations (r=-0.61, p = 0.048) were observed between the change in CD80+ eosinophils and the change in FEV1/FVC% predicted and MEF25% after omalizumab treatment. Conclusion Our findings show a unique role of omalizumab in reducing co-stimulator molecules expression on eosinophil and serum eotaxin-1 levels in allergic asthmatics with comorbidities.