Differential expression of periostin in the nasal polyp may represent distinct histological features of chronic rhinosinusitis.

OBJECTIVE:Chronic rhinosinusitis (CRS) is thought to be a multifactorial disease, and it is classified into a number of subtypes according to clinicohistological features. Periostin, a 90-kDa secreted protein, was reported to exist in nasal polyps (NPs) associated with CRS. We compared the expression of periostin with the degree of eosinophilic infiltration as well as tissue remodeling. MATERIALS AND METHODS:Tissue samples were collected from 28 patients of CRS with NPs, and clinicohistological features were evaluated. The pattern of periostin expression was assessed immunohistochemically. RESULT:Two patterns of periostin expression was observed in nasal polyps: "diffuse type", in which periostin was expressed throughout the lamina propria starting just below the basement membrane, and "superficial type", in which the protein was detected only in the subepithelial layers between the basement membrane and the nasal gland. The average infiltrated eosinophil count in the diffuse type was significantly higher than that in the superficial type (diffuse type 360.5±393.0 vs. superficial type 8.46±13.81, p=0.001). Tissue remodeling was observed in 17 (85.0%) of the 20 diffuse-type nasal polyps, but only in one (12.5%) of the eight superficial-type nasal polyps (p<0.001). CONCLUSION:At least two distinct patterns of periostin expression were observed in the nasal polyps associated with CRS in accordance with the heterogeneous mechanisms underlying the pathogenesis of CRS with NPs.