Methods: Blood and nasal lavage fluid (NLF) was collected from subjects with chronic rhinosinusitis with nasal polyps (CRSwNP) and aspirin exacerbated respiratory disease (AERD) or normal controls. Heparin-anticoagulated blood was centrifuged to obtain platelet-free plasma. Basophil MPs (BasoMPs:CD203c(+)c-kit(-)MPs) in plasma (plasma-BasoMPs) and in NLF (NLF-BasoMPs) were detected by flow cytometry. Basophil activation was evaluated by analyzing the mean fluorescence intensity of CD203c (CD203cMFI) on BasoMPs.
Results: Blood samples were collected from 9 control, 10 CRSwNP, and 9 AERD subjects. NLF was collected from 22 control, 22 CRSwNP with aspirin tolerant asthma (CRSwNP+ATA) and 29 AERD subjects. When compared with control, plasma-BasoMPs were not increased in CRSwNP (p=0.93) or AERD (p=0.23). CD203c MFI on plasma-BasoMPs was not increased in these two groups (CRSwNP:p=0.74, AERD:p=0.35). NLF-BasoMPs were increased compared to controls but only in AERD (2.5-fold, p<0.03), not in CRSwNP+ATA (p=0.59). CD203cMFI on NLF-BasoMPs was increased in CRSwNP+ATA (p<0.04) and AERD (p<0.0001) compared to controls.
Conclusions : Based on plasma-BasoMP levels, the degree of basophil activation in the circulation of CRSwNP and AERD was the same as in control. Based on NLF-BasoMP levels, basophils were more highly activated in nasal tissues of AERD compared to CRSwNP+ATA or controls. Basophil MPs are potential biomarkers for basophil activation in vivo in patients.