The Bronchial challenge with D. pteronyssinus enhanced pro-proliferative properties of inflammatory eosinophils subtype in allergic asthma patients

Abstract

Introduction: Allergic asthma (AA) exacerbation is associated with increased eosinophilic airway inflammation. Two eosinophils subtypes were identified: lung-resident eosinophils (rEOS) and inflammatory eosinophils (iEOS), which differ in their biological features. Aim: To investigate the effect of bronchial allergen challenge (BAC) with D. pteronyssinus on rEOS and iEOS pro-proliferative properties in AA patients. Methods: We studied 13 AA patients before and 24h after BAC with D. pteronyssinus. Peripheral blood eosinophils were isolated by high-density centrifugation and magnetic separation, subtyping – with antibodies against adhesion molecule CD62L. An individual co-culture of eosinophils and immortalized ASM cells was prepared. Eosinophil subtypes effect on ASM cell proliferation was measured after 72 h of incubation by Alamar Blue assay. Results: At baseline, rEOS from AA patients had a more pronounced effect on ASM cell proliferation – ASM cell number increased by 21.2±4.5% in co-culture with rEOS, while with iEOS – by 7.0±3.4%, compared with control ASM cells without incubation with eosinophils (p<0.001). After BAC, rEOS pro-proliferative properties remain similar – rEOS increased ASM cell proliferation by 29.8±6.2%. However, BAC significantly enhanced the iEOS effect on ASM cell proliferation – ASM cell number increased by 18.1±3.8% (p<0.005). Conclusions: BAC with D. pteronyssinus significantly enhanced iEOS pro-proliferative properties without an effect on rEOS in AA patients.