Serum microRNA-223 as a potential biomarker for allergic rhinitis and its correlation to eosinophil-derived neurotoxin.

Allergic rhinitis (AR) is a global health problem. It is an inflammatory condition defined by a malfunction of the immune system's regulatory mechanism. MicroRNA-223 (miRNA-223) has been linked to the modulation of AR in the last few years. The goal of this study was to determine whether miR-223 can be utilized as a potential biomarker for diagnosis of AR, and whether it correlates with the total nasal symptom score (TNSS) along with serum interleukin-17 (IL-17), interleukin-4 levels (IL-4) and eosinophil-derived neurotoxin (EDN). This study included 76 adult participants, consisted of 38 AR patients and 38 apparently healthy controls. Serum levels of miR-223 were assayed using real-time PCR. The levels of EDN, IL-17 and IL-4 in the serum were determined using an enzyme-linked immunosorbent assay. The optimal cutoff value for the analyzed factors to diagnose AR was determined using a receiver operating characteristic curve analysis (ROC). The demographic features (age and gender) of the two study groups were matched. Patients with pollen-induced AR had significantly higher levels of miR-223 in their serum compared to the controls (median = 3.82; median = 1.03, respectively, p < 0.001). In AR cases, a significant positive association was observed between miR-223 expression level and TNSS (r = 0.492, p = 0.002), EDN serum level (r = 0.427, p = 0.008), IL-4 serum level (r = 0.341, p = 0.036) and IL-17 serum level (r = 0.324, p = 0.047). MiR-223, at a cutoff value of 1.18, had a sensitivity and specificity of 94.9 % and 92.5%, respectively. In conclusion, miR-223 expression is significantly greater in blood of AR patients. There is a significant association between miR-223 and clinical severity of AR, each of IL-17 and IL-4 as well as EDN. Therefore, miR-223 may be employed as an effective biomarker for AR diagnosis.