Background: The interaction between epithelial cells and immune cells plays an important role in the pathogenesis of chronic rhinosinusitis with nasal polyps (CRSwNP); however, the mechanism or mechanisms underlying T H-biased inflammation in this process are largely unknown. Profiling protein expression in patients with CRSwNP by using shotgun proteomics suggested that cystatin SN (CST1), a type 2 cysteine protease inhibitor, might play a role because this was expressed with the greatest difference in patients with eosinophilic chronic rhinosinusitis with nasal polyps (ECRSwNP) and those with noneosinophilic chronic rhinosinusitis with nasal polyps (nonECRSwNP). Objectives: We sought to investigate the expression and role of CST1 in modulating eosinophilic inflammation in patients with CRSwNP. Methods: Sinonasal tissues were collected from 192 patients with ECRSwNP, 52 patients with nonECRSwNP, and 40 control subjects. CST1 mRNA expression, localization, and concentration in the tissues were measured by using real-time PCR, in situ hybridization, immunohistochemistry, and an ELISA. Recombinant CST1 was used to further explore the function of the molecule in dispersed nasal polyp cells and eosinophils extracted from polyp tissues and peripheral blood. Results: CST1 was mainly expressed by epithelial cells and significantly increased in patients with ECRSwNP but decreased in patients with nonECRSwNP compared with that in control subjects. CST1 expression was further increased in patients with ECRSwNP and comorbid asthma and correlated with eosinophil percentages in tissue samples. CST1 was induced by IL-4 and IL-13 in tissue from both patients with ECRSwNP and those with nonECRSwNP and repressed by IL-17A in patients with nonECRSwNP in the presence of neutrophils. CST1 enhanced eosinophil activation and recruitment through induction of IL-5. Conclusion: Epithelium-derived CST1 modulates eosinophil activation and recruitment, expression of which could be regulated by T H 2 and T H 17 cytokines.

Background: Tissue eosinophils have been shown to be associated with polyp recurrence in chronic rhinosinusitis with nasal polyps (CRSwNP). We addressed whether the mRNA levels of Charcot-Leyden Crystal (CLC) in nasal brushing samples, a molecule mainly released from activated eosinophils, could serve as an effective non-invasive biomarker to predict polyp recurrence.Methods: A total of 51 patients with CRSwNP completing the postoperative follow-up over a period of 12-18 months were enrolled. Baseline CLC mRNA levels of the nasal brushings collected prior to endoscopic sinus surgery were quantified by quantitative real-time polymerase chain reaction (qRT-PCR). Polyp specimens were collected during surgery and were evaluated for inflammatory cells by histopathologic staining. The patients' baseline characteristics were reviewed and analyzed for associations with recurrence. Logistic regression analysis was performed to determine the predictive factors for polyp recurrence, and receiver operating characteristic (ROC) curves were performed to determine their predictive values.Results: Overall, 25/51(49.02%) patients experienced polyp recurrence during the 12-18 months follow-up. The baseline relative CLC mRNA level in nasal brushing samples was significantly increased in patients with recurrence compared to those without recurrence (p<0.001). ROC curves demonstrated that a cut-off value of -6.419 for the relative CLC mRNA level normalized to GAPDH in nasal brushings predicted the recurrence with 92.00% sensitivities and 88.46% specificities (AUC=0.932, p<0.001). Conclusions:The relative CLC mRNA levels in nasal brushings may serve as a reliable non-invasive biomarker to predict CRSwNP recurrence.

Background Eosinophilic chronic rhinosinusitis with nasal polyps (ECRSwNP) is a distinct phenotype of chronic rhinosinusitis with nasal polyps (CRSwNP), with many significantly different clinical features from non-eosinophilic chronic rhinosinusitis with nasal polyps (non-ECRSwNP). Thus, identification of subtypes is crucial for precise treatment. Immunohistology is a reliable way to present the subtypes; however, the results mainly depend on the observation of pathologist, and the method with automatic readout and the corresponding biomarkers is lacking. Objective The purpose of our research was to explore the predictive value of quantitative reverse transcription polymerase chain reaction (qRT-PCR) as an alternative method and messenger RNA (mRNA) expression of Charcot–Leyden crystals (CLC) as a corresponding target for ECRSwNP, which may benefit the automatized judgment. Method CLC mRNA levels in tissue samples from 48 CRSwNP patients and 10 controls were evaluated by quantitative real-time PCR. Hematoxylin and eosin staining was performed for histological assessment of CRSwNP and subtyping as ECRSwNP and non-ECRSwNP. Factors associated with ECRSwNP were determined with logistic regression analysis, the predictive value was presented by a receiver operating characteristic (ROC) curve, and optimal cutoff points of the predictors were identified as the Youden index. Results mRNA level of CLC in ECRSwNP was significantly elevated compared to either non-ECRSwNP group or control group, with no significant difference between non-ECRSwNP patients and controls. CLC mRNA levels were positively correlated with percentages of tissue eosinophil and peripheral blood eosinophil ( P < .001, r = .683; P = .003, r = .420, respectively). Logistic regression analysis revealed CLC mRNA level and blood eosinophil percentages were prediagnosis factors ( P = .007, P = .045, respectively) for ECRSwNP. ROC curves analysis indicated the area under the curve (AUC) of CLC mRNA level was 0.948 which was superior to the blood eosinophil percentage (AUC = 0.797; P = .044) as an optimal biomarker to predict ECRSwNP. Conclusions CLC mRNA levels based on the qRT-PCR may serve as a reliable and alternative method for the identification of ECRSwNP.