Pre- and postoperative blood neutrophil-to-lymphocyte and eosinophil-to-lymphocyte ratios in patients with sinonasal polyps: A preliminary investigation

Background: Identifying specific endotypes within the broad picture of chronic rhinosinusitis with nasal polyps (CRSwNP), by using biomarkers for instance, remains a challenge. The prognostic role of the neutrophil-to-lymphocyte ratio (NLR) and the eosinophil-to-lymphocyte ratio (ELR) as potential markers of inflammation has already been discussed. Objective: The aim of the present study was to compare NLR and ELR before and after endoscopic sinus surgery (ESS) and nasal mometasone furoate for CRSwNP by stratifying patients by their clinical and histologic features. Methods: The study included 115 consecutive patients with CRSwNP treated with ESS and nasal mometasone furoate, with a postoperative follow-up of >12 months. Eosinophilic-type CRSwNP was histopathologically defined after hematoxylin and eosin tissue staining. Results: In the subcohort of patients with an histologic diagnosis of eosinophilic-type CRSwNP, the mean +/- standard deviation ELR significantly decreased after surgery (0.22 +/- 0.16 versus 0.18 +/- 0.12; p +/- 0.04), whereas, among patients with a histologic diagnosis of noneosinophilic-type CRSwNP, the mean NLR significantly decreased after surgery (1.98 +/- 0.98 versus 1.90 +/- 0.90; p = 0.04). Conclusion: Different CRSwNP endotypes are characterized by different biohumoral patterns. It is reasonable to assume that surgery enables clearance of the polyps and polypoid mucosa, which reduces the load of antigens that triggers the inflammation. Consistent with the above-mentioned biologic mechanism, ESS could correspond to a reduction in blood ELR values and eosinophil count in eosinophilic-type CRSwNP. Analysis of the data did not demonstrate an added value of measuring pre-versus postoperative ELR compared with measuring the blood eosinophil count. When used after ESS, topical corticosteroids also had more significant anti-inflammatory effects. As for the subcohort of patients with noneosinophilic CRSwNP, the fact that the mean NLR dropped significantly after surgery was definitely an original finding. Unlike eosinophilic inflammation, the inflammatory patterns seen in noneosinophilic CRSwNP are still poorly understood.