A substantial neutrophilic inflammation as regular part of severe type 2 chronic rhinosinusitis with nasal polyps.
BACKGROUND
Chronic rhinosinusitis with nasal polyps (CRSwNP) is generally associated with severe type 2 immune reactions in the white population. However, recent findings suggest an additional role for neutrophils in severe type 2 inflammation.


OBJECTIVE
This study aimed to characterize the neutrophilic inflammation in CRSwNP and its relation to eosinophilic inflammation in severe type 2 immune reactions.


METHODS
The presence and activation of neutrophils and eosinophils was analyzed in CRS without NP and CRSwNP by measuring cell and activation markers via immunohistochemistry, immunofluorescence, Luminex assay, ELISA, UniCAP, fluorescence-activated cell sorting, and PCR. Differential neutrophil migration was assessed via Boyden-chamber assay and neutrophil survival was analyzed via flow cytometry.


RESULTS
Both CRS without NP and CRSwNP displayed variable degrees of eosinophilic and neutrophilic inflammation, with a profound neutrophilic infiltration and activation in type 2 CRSwNP, associated with eosinophil extracellular traps cell death and Charcot-Leyden crystals, but independent of IL-17. Neutrophil extracellular traps cell death in CRSwNP was associated with bacterial colonization, however, neutrophils were less prone to undergo neutrophil extracellular traps cell death in the tissue of patients with severe type 2 CRSwNP. Neutrophils did not show increased migration nor survival in the CRSwNP environment in vitro.


CONCLUSIONS
This study demonstrated a severe neutrophilic inflammation associated with severe eosinophilic type 2 inflammatory CRSwNP, the role of which needs further study.
['Delemarre|Tim|T|', 'Holtappels|Gabriele|G|', 'De Ruyck|Natalie|N|', 'Zhang|Nan|N|', 'Nauwynck|Hans|H|', 'Bachert|Claus|C|', 'Gevaert|Elien|E|']
D000293:Adolescent D000328:Adult D000368:Aged D000369:Aged, 80 and over D002908:Chronic Disease D005260:Female D006801:Humans D007249:Inflammation D008297:Male D008875:Middle Aged D009298:Nasal Polyps D009504:Neutrophils D012220:Rhinitis D012720:Severity of Illness Index D012852:Sinusitis
neutrophils CRSwNP type 2 inflammation Charcot-Leyden crystals IL-17 CRSsNP NETosis