Airway inflammation in thunderstorm asthma.

Area of Science:

• Allergy and Immunology
• Respiratory Medicine
• Environmental Health

Background:

• Epidemic thunderstorm asthma events occur globally, but the underlying airway inflammation remains poorly understood.
• Characterizing airway inflammation is crucial for understanding and managing these acute asthma exacerbations.

Purpose of the Study:

• To characterize airway inflammation in patients experiencing thunderstorm-induced asthma.
• To compare airway inflammation markers between thunderstorm asthma cases and control groups.

Main Methods:

• Recruited 6 patients with acute asthma post-thunderstorm, comparing them to 12 atopic asthmatics and 6 corticosteroid-naive asthmatics.
• Conducted spirometry, sputum induction, and allergy skin tests acutely and at 4-week follow-up.
• Analyzed sputum for eosinophil counts, eosinophil cationic protein (ECP), and interleukin-5 (IL-5) positive cells.

Main Results:

• Thunderstorm asthma cases showed significantly higher sputum eosinophils (14.8%) and ECP levels compared to controls.
• Elevated IL-5 positive cells (30%) were observed in thunderstorm asthma cases, indicating an inflammatory response.
• Adjusted analysis revealed a 2.4-fold increased risk of elevated sputum eosinophils in thunderstorm asthma cases, even considering inhaled corticosteroid (ICS) use.

Conclusions:

• Thunderstorm asthma is characterized by significant airway inflammation, specifically IL-5-mediated sputum eosinophilia and eosinophil degranulation.
• Findings support allergen exposure, likely from a grass pollen deluge during thunderstorms, as the primary cause of these epidemic asthma events.
• The study provides insights into the inflammatory mechanisms driving severe asthma exacerbations triggered by environmental factors.