Correlation between nasal nitric oxide and its metabolites, RANTES, IL-5 in allergic rhinitis and chronic rhinosinusitis with nasal polyp

Abstract

Background and Objectives Nasal nitric oxide (nNO) varies according to the patency of the ostiomeatal unit of paranasal sinuses and the inflammatory state of the nasal cavity. There have been two measurement methods for nNO: direct measurement of nNO and indirect measurement of NO metabolites or the NO synthase enzyme. The aim of this study is to investigate the difference in nNO between allergic rhinitis (AR) and chronic rhinosinusitis with nasal polyp (CRSwNP) patients and the correlation of the direct measurement of nNO and indirect measurement of nNO metabolites (nNOx-), RANTES, and IL-5 in each group.

Subjects and Methods Fifteen patients with AR, 15 patients with CRSwNP, and 15 patients with septal deviation as a control group were enrolled. We measured the nNO level using a chemiluminescence analyzer and the amount of NO metabolites, RANTES, and IL-5 in nasal lavage fluid using the ELISA method.

Results Nasal NO levels were significantly higher in AR than the control (195.7±39.6 vs 159.4±25.8 ppb, p=0.027) and in the control compared to CRSwNP (159.4±25.8 vs 45.6±29.5 ppb, p=0.001). NO metabolites and IL-5 levels were higher in AR, but there was no statistically significant difference. The RANTES levels were significantly higher in AR than CRSwNP (117.4±159.2 vs 6.2±6.4 pg/mL, p=0.003) and in the control compared to CRSwNP (42.1±28.3 vs 6.2±6.4 pg/mL, p=0.003). There was no significant correlation between nNO and nNOx-, RANTES, IL-5, and clinical parameters except for the olfactory test score in AR. There was a negative correlation between nNO and the olfactory test score in AR (r=-0.590, p=0.034).

Conclusion Nasal NO concentration increased in AR and decreased in CRSwNP. However, nNO metabolites and IL-5 in nasal secretion did not show any difference or correlation with nNO. RANTES increased in AR but showed no correlation with nNO. Direct measurement of nNO could be a potentially useful biomarker of AR and CRSwNP compared to indirect measurement of NO metabolites, cytokines, and chemokine in nasal secretion.