Background
Microparticles (MPs) are submicron sized shed membrane vesicles released from activated or injured cells and are detectable by flow cytometry. MP levels have been utilized as biomarkers to evaluate cell injury or activation in patients with pathological conditions.
Objective
To compare MP types and levels in nasal lavage fluids (NLFs) from controls and patients with chronic rhinosinusitis without nasal polyps (CRSsNP), CRS with NP (CRSwNP) and aspirin exacerbated respiratory disease (AERD).
Methods
We collected NLFs from CRSsNP (n=33), CRSwNP (n=45), AERD (n=31), and control (n=24) subjects. Standardized flow cytometry methods were used to characterize the following MP types; endothelial MPs, epithelial MPs (EpCAM(+)MPs, E-cadherin(+)MPs), platelet MPs (CD31(+)CD41(+)MPs), eosinophil MPs (EMR1(+)MPs), mast cell MPs (FcεRI(+)c-kit(+)MPs) and basophil MPs (CD203c(+)c-kit(−)MPs). Basophil activation was evaluated by the MFI of CD203c (CD203cMFI) on basophil MPs.
Results
Activated mast cell MPs (CD137(+)FcεRI(+)c-kit(+)MPs) were significantly increased in NLFs compared to controls in CRSsNP (2.3-fold, p<0.02), CRSwNP (2.3-fold, p<0.03) and in AERD (7.4-fold, p<0.0001). Platelet MPs (3.5-fold, p<0.01) and basophil MPs (2.5-fold, p<0.05) were increased only in AERD. CD203cMFI on MPs was increased in CRSwNP (p<0.002) and AERD (p<0.0001), but not CRSsNP. EpCAM(+)epithelial MPs in CRSwNP were no different from control (p= 0.91) and lower than those in CRSsNP (p<0.02) and AERD (p<0.002).
Conclusion
Based on released MPs, mast cells, platelets, and basophils were more highly activated in AERD than in CRS. Epithelial injury was lower in CRSwNP than in CRSsNP and AERD. MP analysis may help identify phenotypes of CRS, and in distinguishing AERD from CRSwNP.