Effective omalizumab treatment influenced eosinophil function in severe allergic asthmatics

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 explore the influence of effective omalizumab treatment on circulating eosinophils.

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. For eosinophil functional evaluation, peripheral blood eosinophils were separated; and examined the expression of human leukocyte antigen (HLA)-DR and co-stimulatory molecules cluster of differentiation (CD) 80, CD86 and CD40 by Flow Cytometry and serum were to measure the concentration of eotaxin-1 before and after 16 weeks of omalizumab treatment.

Totally 32 allergic asthma patients who responded positively to omalizumab treatment were included. Omalizumab responders showed a significant decline in the 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 forced expiratory volume in the first second (FEV1)/forced vital capacity (FVC)% predicted and maximal expiratory flow (MEF) 25% after omalizumab treatment. Omalizumab improved FEV1/FVC% predicted (3.88, P=0.033), fractional exhaled nitric oxide (FeNO, -22.24, P=0.028), asthma control test (ACT, 4.22, P<0.001), mini asthma quality of life questionnaire (mini-AQLQ, -14.44, P=0.019), Leicester cough questionnaire (LCQ, 3.03, P=0.009) and visual analogue scale (VAS) for allergic symptoms (-13.00, P=0.001) in patients with severe allergic asthma statistically; reduced mini rhino-conjunctivitis quality of life questionnaire (mini-RQLQ, -8.50, P=0.047), and self-rating anxiety scale (SAS, -5.08, P=0.040) in allergic asthmatics with concomitant allergic rhinitis (AR) or anxiety, respectively.

Our findings show a unique role of omalizumab in reducing co-stimulatory molecules expression on eosinophil and serum eotaxin-1 levels in severe allergic asthmatics accompanied by improvement of multiple clinical parameters of allergic diseases.