Methods: Nasal polyp tissues from adult patients with CRS with eosinophilic polyps (ECRS; n=13, tissue eosinophil count >70 HPF) and CRS with non-eosinophilic polyps (NECRS; n=10, tissue eosinophil count <70 HPF) were diagnosed on the basis of the JESREC Study (Allergy. 2015 Aug; 70(8):995-1003.). Those and nasal mucosa biopsy specimens from age-matched control subjects (n=7) were analyzed by a microarray system to determine their comprehensive gene expression profiles.
Results: Expression of type 2- and eosinophil-related genes (IL13, IL5, IL1RL1, CLC, CCL26 and CCL23) was increased in ECRS compared with the controls, and the results were comparable to those for CRSwNP in Western countries. In contrast, expression of type 1- and neutrophil-related genes (CSF3, CXCL10, IL8, IFNG and IL1B) was increased in NECRS. A primary component analysis revealed three distinct clusters, reflecting ECRS, NECRS and controls. However, expression of monocyte/macrophage- and lymphocyte-related genes (CCL18, MARCO, F13A1, CD209 and IL2RA) was increased in both ECRS and NECRS.
Conclusions: The characteristic gene expression profiles indicated the existence of at least two separate CRSwNP endotypes in Japanese patients. Their shared gene expression profiles may help understand the pathogenesis of nasal polyps.