Pilot Study of the Ex Vivo Blood Leukocytes’ Proteomic Response to Prednisone Stimulation in Corticosteroid-responsive Asthma

Background: Leukocytes are key cellular effectors of inflammation in asthma and understanding their function in this disease is of crucial importance. Blood leukocytes reflect the actions of their counterparts in the lungs and they can be obtained through minimal invasive procedures as part of the peripheral blood. Objective: The aim of the study was to identify proteins in blood leukocyte proteomes that respond to ex vivo treatment by prednisone in order to pinpoint candidates for predictive biomarkers in corticosteroid- responsive asthma. Methods: The study included five children diagnosed with asthma and five healthy children. After the ex vivo treatment of blood samples with prednisone, lysis of erythrocytes was performed and proteins were extracted from the remaining leukocytes by ultrasonic disintegration. Protein extracts were analyzed by reversed phase nano-liquidchromatography–tandem mass spectrometry (LC–MS/MS). Results: The stimulation of asthmatics' leukocytes with prednisone has led to an increase in the levels of FYB (fold change 3.4) and LYZ (fold change 2.2) with a statistical significance of p<0.005. The two proteins with expressions significantly altered upon the prednisone treatment should be further explored as tools to evaluate the patient's response before therapy administration, especially when lung function measurements are not possible, as is the case with young pediatric patients. Conclusion: The approach that entails ex vivo response of blood leukocytes to therapeutics can facilitate asthma management and help overcome the need for therapeutic adjustments in a clinical setting.