OBJECTIVETo evaluate the expressions of interleukin (IL) 13 and its receptor IL-13Rα2 in eosinophilic chronic rhinosinusitis with nasal polyps (ECRSwNP) and non-ECRSwNP and their clinicopathological implications.

METHODSA total of 60 consecutive patients with CRSwNP who underwent endoscopic sinus surgery (ESS) were divided into two groups of ECRSwNP (n = 27) and non-ECRSwNP (n = 33) based on tissue eosinophil count (more than five cells per high power field) with postoperative pathological examination. Before ESS,the severities of symptoms, nasal polyps, and sinonasal diseases on CT were scored, peripheral blood eosinophil count and percentage, and total serum. IgE level were measured. IL-13 and IL-13Rα2 expressions in polyp tissues were examined with immunohistochemistry. SPSS 16.0 software was used to analyze the data.

RESULTSThere was no significant differences between ECRSwNP and non-ECRSwNP groups in the mean symptom scores (t = 0.102, P > 0.05), but ECRSwNP, compared to non- ECRSwNP, demonstrated a higher incidence of bilateral polyps (χ2 = 15.879, P < 0.01), a higher mean score of nasal polyps (3.6 ± 1.1 vs 2.1 ± 0.8, t = 4.009, P < 0.01) or diseases on CT (t = 4.428, P < 0.01). And also a significant difference existed between two groups in mean blood eosinophil count (t = 3.148, P < 0.01) or percentage (t =3.038, P < 0.01), but no significant difference in total serum levels of IgE (t = 0.659, P > 0.05). There was a closed correlation between tissue eosinophil count and blood eosinophil count (r = 0.683, P < 0.01) or percentage (r = 0.631, P < 0.01) in ECRSwNP, but not in non-ECRSwNP. The expressions of both IL-13 and IL-13Rα2 increased significantly in ECRSwNP compared to non-ECRSwNP ( scores 8.1 ± 1.6 vs. 5.4 ± 1.6; 8.8 ± 1.4 vs. 4.8 ± 1.6, t value was 4.749, 8.010, P < 0.01).

CONCLUSIONSIL-13 and IL-13Rα2 are associated closely with pathogenesis o ECRSwNP. Subtyping CRSwNP and studying underly mechanism can be helpful to make treatment strategy for CRSwNP.