Optimizing Protein Harvest From Nasal Brushings for Determining Local Allergy Responses

Abstract

Background Rhinitis is a highly prevalent yet often misdiagnosed condition. Patients who have local allergic rhinitis are regularly mislabeled as having a nonallergic etiology. Thus, a highly accurate, reproducible, and noninvasive assessment, which can be performed quickly and with minimal discomfort to the patient, is required. Objective The aim of this research was to identify the efficiency of various nasal brushes as tools for harvest and collection of epithelial proteins and its suitability for identification of rhinitis. Methods Nasal epithelial mucosa samples were taken from patients undergoing turbinate surgery using a cytology brush, a dental brush, and a nasal curette in random order. After washing in phosphate-buffered saline, the suspended cells were sonicated. Total protein content was assessed for all samples by bicinchoninic acid assay measured using a Nanodrop machine. Identification of nasal-specific immunoglobulin E (spIgE) was then assessed using immunoassay and compared to the patient's allergic status from epicutaneous and serum testing. The lower threshold limit for the spIgE in nasal brushings was determined using the results of serum spIgE tests as the reference. The diagnostic accuracy of this new established cutoff value was determined. Results The cytology brush was found to be the optimal tool for maximal nasal mucosa protein collection followed by dental brush and nasal curette (0.75 ± 0.45 mg/mL vs 0.43 ± 0.24 mg/mL vs 0.071 ± 0.55 mg/mL, respectively; P < .01). The optimal cutoff value of nasal spIgE from the cytology nasal brushings was 0.14 kUA/L to predict allergic status from serum testing. This gave a sensitivity of 75%, specificity of 86%, positive predictive value of 74%, likelihood ration positive of 5.40, and diagnostic odds ratio of 18.62. Conclusion The cytology brush is the optimal tool for protein collection. This is an easy and direct method to sample the nasal mucosa for assessment of nasal allergy or future biomarkers.

International consensus statement on allergy and rhinology: Allergic rhinitis – 2023

“…Cut‐off values for nasal sIgE levels that indicate a diagnosis of AR are debated and consensus has yet to be established. It is generally accepted that levels of nasal sIgE will be lower than levels of serum sIgE in patients with AR 1357,1361,1362 (Table X.C.3).…”

Estado actual del conocimiento en rinitis alérgica local

“…42 Hatem et al realizaron un estudio prospectivo multicéntrico, en el cual incluyeron 1230 pacientes con rinitis crónica; encontraron que la prueba de provocación nasal puede identificar RAL en 84.6 % de los pacientes que tenían prueba de punción cutánea negativa y que previamente fueron considerados con RNA. 43 Las principales limitaciones dentro de este enfoque diagnóstico incluyen la baja sensibilidad de la prueba para la medición de IgEs en el lavado nasal (22 a 40 %) 42,44,45,46,47 y la reproducibilidad de los resultados. 37,48 La prueba de activación de basófilos parece ser otra opción para evaluar la presencia de IgEs; Gómez et al 34 informaron que con esta prueba se pudo diagnosticar al menos 50 % de los casos de RAL por Dermatophagoides pteronyssinus, con valores predictivos positivos de 89 %, es decir, con mayor sensibilidad que la detección de IgE específica nasal.…”

Frontier Knowledge and Novel Therapeutic Modalities for Rhinologic Disease

“…They envisage this to be especially helpful in determining local IgEmediated allergic responses in individuals where systemic markers of atopy are absent. 6 In pursuit of early diagnosis for eosinophilic CRS (eCRS), Ho et al delve into a number of potential systemic biomarkers. 7 eCRS is associated with worse clinical prognosis to non-eCRS patients.…”