Tissue Eosinophils Threshold and its Association with Adult-Onset Asthma in Chronic Rhinosinusitis.

Introduction: Tissue eosinophil counts (TEC) might serve as a biomarker linking chronic rhinosinusitis (CRS) and the presence of adult-onset asthma. This study aimed to determine if TEC in sinus mucosa/polyps in CRS patients is an independent indicator of asthma and to identify its optimal cut-off point.

Methods: This cross-sectional study was conducted on primary CRS patients scheduled for surgery. All patients were assessed by a pulmonologist for asthma diagnosis. Tissues were collected during surgery and evaluated for TEC. Logistic regression and receiver operating characteristic analysis were used to determine significant factors and the optimal cut-off points of TEC associated with asthma.

Results: A total of 103 CRS patients were included. Ten patients (9.7%) had underlying asthma, while 13 (12.6%) were first diagnosed by the pulmonologist. TEC ≥40 cells per high-powered field (HPF) exhibited a significant correlation with asthma (area under the curve = 0.71, p < 0.001). The sensitivity of this cut-off point was 0.70 (95% confidence interval [CI] = 0.47-0.87), and specificity was 0.66 (95% CI = 0.55-0.76). Positive predictive value and negative predictive value were 0.37 and 0.88, respectively. The cut-off point significantly associated with the presence of asthma, with an adjusted odds ratio of 3.13 (95% CI = 1.05-9.35, p = 0.04), controlling for polyps, allergic rhinitis, and computerized tomography (CT) score.

Conclusion: TEC in CRS patients can help determine the presence of adult-onset asthma, with an optimal threshold of ≥40 cells/HPF. This threshold is significantly associated with asthma independent of polyps, allergy, and CT score.