Basophil Activation Test useful Alternative to Nasal Allergen Challenge Test for Allergic Rhinitis, suggests study

Allergic rhinitis (AR) is an inflammatory condition of the nasal mucosa associated with increased morbidity and reduced quality of life. Skin prick test (SPT) and serum allergen-specific (sIgE) are some of the tests for AR after a thorough clinical examination. nasal allergen challenge (NAC) is advised to individuals whose clinical history is not sufficiently clarifying regarding the relevance of the sensitizations detected. Some individuals have negative SPT tests but positive NAC which is called local allergic rhinitis (LAR). Some may have a combination of allergies with and without SPT positivity called dual allergic rhinitis (DAR). Research shows that BAT can be used as a standard test for AR. Research shows that BAT can be an alternative to NAC for allergic patients with an IgE-dependent endotype. Hence, researchers conducted a study to investigate the diagnostic performance of BAT for allergic phenotypes of rhinitis.

A prospective study included patients ≥18 years with chronic rhinitis for ≥2 years. They were subjected to NAC with the allergens from Dermatophagoides pteronyssinus (DP), Alternaria alternata (AA), Grass pollen (GP), and Olea europaea pollen (OP). Rhinitis subjects underwent a skin prick test (SPT) with relevant allergens. Patients were classified into allergic rhinitis (AR, positive NAC and SPT), local allergic rhinitis (LAR, positive NAC, and negative SPT), dual allergic rhinitis (DAR, de-fined as AR for ≥1 allergen and LAR for ≥1 allergen), and non-allergic rhinitis (NAR, negative NAC and SPT) phenotypes. BAT was used to measure allergic reactions in various samples. Shapiro-Wilk tests were used to assess data normality, ROC curves were used to assess the diagnostic accuracy of BAT.

Results:

• A total of 47 AR, 31 DAR, 26 LAR, 12 NAR, and 21 control subjects were recruited.
• The best positivity cut-offs of BAT for DP-, AA-, GP- and OP-driven allergy (all phenotypes) were a %CD63 cells of 8.650, 14.250, 26.200, and 12.780, respectively (AUC 0.851, 0.701, 0.887, and 0.921, respectively).
• Sensitivity, specificity, negative, and positive predictive values of BAT (all phenotypes) ranged from 43.5%(AA)-83.3%(OP), 88.9%(GP)-100%(AA), 87%(GP)-100%(AA), and61.1%(DP)-80.0%(pollens), respectively.
• BAT identified 79%–100% of SPT-positive allergies (AR and DAR), and 25%–75% of SPT-negative allergies (LAR and DAR), while ≤10%of NAR/HC subjects tested positive.
• BAT positivity correlated with rhinitis severity in LAR patients (p = 0.018) and was associated with conjunctivitis (p = 0.015) in allergic subjects.

Thus, the study concluded that BAT can be effectively used for various rhinitis phenotypes. This comes after BAT positivity was linked to severe rhinitis in LAR and conjunctivitis in allergic individuals. As BAT can widely discriminate between allergic and non-allergic rhinitis with high sensitivity and specificity this can be used for early diagnosis and a tailored treatment plan.

Further reading: Testera-Montes A, Ariza A, Sola-Martinez RA, et al. Investigation of the diagnostic accuracy of basophil activation test for allergic phenotypes of rhinitis. Allergy. Published online November 5, 2024. doi:10.1111/all.16390