Nasal cytology can predict clinical efficacy of subcutaneous immunotherapy in intermittent allergic rhinitis

Introduction
Allergen immunotherapy (AIT) is the only disease-modifying treatment option available for patients with IgE-mediated allergic rhinitis. The identification of specific biomarkers, which may predict response to AIT, is currently an active field of research in the aspect of recommended personalization of medicine.

Aim
To assess the changes in rhinological parameters in intermittent allergic rhinitis (IAR) patients resulting from subcutaneous immunotherapy (SCIT).

Material and methods
Forty-two patients (female: 19; 45%) with IAR qualified for subcutaneous immunotherapy were enrolled in this study. Fourteen (33.3%) patients were desensitized with grass pollen allergen extracts, 12 (28.6%) with tree pollen allergen extracts, and 16 (38.1%) with grass and tree pollen allergen extracts. The patients were evaluated before AIT during the pollen season and in the next pollen season after introduction of subcutaneous immunotherapy. On both occasions, determination of total nasal symptom score (TNSS), rhinomanometry and nasal cytology were performed.

Results
All examined parameters significantly improved after one course of allergen immunotherapy: the percentage of eosinophils in nasal mucosa, TNSS and nasal resistance decreased, whereas the nasal flow rate increased. The decrease in percentage of nasal eosinophils significantly correlated with improvement in TNSS (rs = 0.39, p < 0.05) and was the highest in the subgroup sensitive to grass pollen (44.5 (40–52)).

Conclusions
The rhinological assessment confirmed high effectiveness of SCIT in intermittent allergic rhinitis. A high percentage of eosinophils in nasal cytology before subcutaneous immunotherapy can predict its clinical efficacy for intermittent allergic rhinitis, especially in grass pollen allergy.