Diagnosis and management of nonallergic rhinitis with eosinophilia syndrome using cystatin SN together with symptoms

BACKGROUND: The diagnosis and treatment of nonallergic rhinitis with eosinophilia syndrome (NARES) remain controversial. The aim of this study was to evaluate whether Cystatin SN together with symptoms can be used to diagnose NARES and to measure the efficiency of medical treatment. METHODS: Seventy-five patients with chronic rhinitis (CR) and 18 control subjects were enrolled. Their clinical characteristics were reviewed and laboratory parameters were evaluated. The concentration of Cystatin SN in nasal secretions was determined using the enzyme-linked immunosorbent assay. The histological assessment of Cystatin SN in the nasal mucosa was conducted by hematoxylin and eosin staining. The logistic regression and receiver operating characteristic curves were used to assess the predictive value of parameters for NARES. RESULTS: Nasal obstruction, sneezing, loss of smell, and total visual analogue scale (VAS) score were significantly different among the patients with CR. In particular, olfaction score was higher in patients with NARES than in those without NARES (AR, LAR, or IR). Similarly, the Cystatin SN level was significantly different between the control subjects and patients with CR. After treatment for 2 weeks, the Cystatin SN level and VAS score were significantly decreased in the NARES group. The accuracy of Cystatin SN together with local sIgE and loss of smell to diagnose NARES was up to 0.987 (sensitivity, 100%; specificity, 93.1%). CONCLUSIONS: Cystatin SN with local sIgE and loss of smell may serve as one of the reliable and alternative biomarkers for the diagnosis of NARES and be used to evaluate disease severity and NARES treatment efficacy.