Exhaled Volatile Organic Compounds Identify Allergic Patients Among Individuals With Chronic Rhinitis

Area of Science:

• Immunology
• Respiratory Medicine
• Biochemistry

Background:

• Allergic rhinitis (AR) and local allergic rhinitis (LAR) diagnosis relies on nasal allergen challenge (NAC), a method with limited clinical application.
• Investigating volatile organic compounds (VOCs) in exhaled breath offers a potential non-invasive method to identify allergic individuals among patients with chronic rhinitis.

Purpose of the Study:

• To determine if VOCs in exhaled breath can differentiate allergic patients (AR, LAR) from non-allergic rhinitis (NAR) and healthy controls (HC).
• To explore the association of specific VOCs with fractional exhaled nitric oxide (FeNO) and blood eosinophil counts.

Main Methods:

• Exhaled breath samples were collected from AR, LAR, NAR, and HC participants before and after NAC.
• Gas chromatography-mass spectrometry was used to analyze VOCs, focusing on saturated hydrocarbons.
• Associations between VOCs, FeNO, and blood eosinophils were assessed.

Main Results:

• A predictive model using decane and nonadecane distinguished allergic from non-allergic subjects with moderate performance (AUC 0.721-0.760).
• These VOCs also differentiated LAR from NAR patients (AUC 0.737).
• Elevated baseline decane and nonadecane were observed in LAR patients, and specific VOCs correlated with higher FeNO levels, suggesting T2 airway inflammation.

Conclusions:

• Exhaled decane and nonadecane show promise as non-invasive biomarkers for allergic inflammation in rhinitis.
• These VOCs may aid in identifying patients who could benefit from NAC.
• Further validation in larger studies is needed to confirm their diagnostic accuracy.