Establishing Urinary Leukotriene E₄ as a Diagnostic Biomarker for Chronic Rhinosinusitis with Comorbid Asthma and Atopy.

Abstract

While urinary leukotriene E₄ (uLTE₄) is a validated biomarker for the cysteinyl leukotriene pathway, which is central to the pathophysiology of asthma, atopy, and chronic rhinosinusitis (CRS), the contributions of comorbid asthma and atopy to uLTE₄ levels in various CRS subtypes have not been previously characterized. We sought to (1) identify reference values for uLTE₄ in subjects with and without CRS and (2) determine how the presence of comorbid atopy and asthma affects uLTE₄ levels in CRS. Tertiary referral medical center. A prospective case-control study was conducted to compare uLTE₄ levels between patients with CRS and healthy controls. Urinary LTE₄ levels were measured by enzyme immunoassay and were adjusted for urinary creatinine concentrations (pg/mg Cr). Patients with CRS were stratified by the clinical comorbidities to determine normative uLTE₄ values for patients with CRS with and without comorbid asthma or atopy. A total of 153 patients (mean age, 47.3; 47.1% female) were included in the study. Patients with CRS demonstrated significantly higher concentrations of uLTE₄ than healthy controls (1652 vs 1065 pg/mg Cr, <i>P</i> = .032). Within the group of patients with CRS, comorbid asthma also individually correlated with elevated uLTE₄ levels (1597 pg/mg Cr, <i>P</i> = .0098). Patients with CRS who did not have comorbid allergy and asthma, in contrast, did not have statistically higher uLTE₄ levels than healthy controls (1142 pg/mg Cr, <i>P</i> = .61). Urinary LTE₄ serves as a noninvasive measure of the inflammatory state in CRS. Comorbid asthma and atopy contribute to elevated uLTE₄ levels in CRS.