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Laryngoscope. 2017 Jan;127(1):E1-E4. doi: 10.1002/lary.26249. Epub 2016 Aug 31.

Secreted P-glycoprotein is a noninvasive biomarker of chronic rhinosinusitis.

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Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts, U.S.A.
Department of Pathology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, U.S.A.
Department of Biomedical Engineering, Boston University, Boston, Massachusetts, U.S.A.



The discovery of noninvasive biomarkers of chronic rhinosinusitis (CRS) is critical to enable our ability to provide prognostic information and targeted medical therapy. Epithelial P-glycoprotein (P-gp) is overexpressed in CRS and exists in an extracellular, secreted form. The objective of this study was to determine whether secreted P-gp concentrations are elevated in CRS and can be used to predict disease severity.


Institutional review board-approved study examining mucus concentrations of P-gp in 36 patients (10 control, 16 CRS without nasal polyps [CRSsNP], and 10 CRS with nasal polyps [CRSwNP]). P-gp concentrations were determined by enzyme-linked immunosorbent assay and normalized to total protein (TP). Clinical indices of disease severity, including the Sino-Nasal Outcomes Test (SNOT-22) and Lund-Mackay score, were collected for all patients.


Secreted P-gp concentration was significantly higher in CRS versus control patients (mean ± standard deviation; 247.8 ± 224.8 vs. 102.4 ± 81.7 pcg P-gp/μg TP, P = 0.022). A threshold value of 250 pcg/μg TP was used to differentiate low versus high secretors. High P-gp secretors with CRS (sNP and wNP, n = 9) demonstrated significantly higher SNOT-22 and Lund-Mackay scores (57.1 ± 7.9 and 13.9 ± 7.3) versus low secretors (38.3 ± 23.9 and 6.8 ± 7.3; P = 0.030 and P = 0.013, respectively) and had a significantly higher proportion of CRSwNP (66.7%) versus the low secretors (23.5%, n = 17, P = 0.046).


P-gp secretion levels are significantly elevated in patients with CRS. High P-gp secretion is associated with a higher incidence of CRSwNP and confers worse subjective and objective measures of disease severity. The presence of elevated P-gp secretion may therefore represent a novel noninvasive biomarker of CRS and could be used to predict patients who may benefit from P-gp inhibitory therapeutic strategies.


NA Laryngoscope, 127:E1-E4, 2017.


P-glycoprotein; biomarker; chronic rhinosinusitis; chronic rhinosinusitis with nasal polyps; secreted P-gp

[Indexed for MEDLINE]

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