Pulmonary Innate Lymphoid Cell Responses during Rhinovirus-induced Asthma Exacerbations In Vivo: A Clinical Trial

Area of Science:

• Immunology
• Respiratory Medicine
• Cell Biology

Background:

• Type 2 innate lymphoid cells (ILC2s) produce cytokines involved in asthma pathogenesis.
• The specific role of ILC2s in virus-induced asthma exacerbations remains unclear.

Purpose of the Study:

• To investigate pulmonary innate lymphoid cell (ILC) responses after experimental rhinovirus challenge in moderate asthma patients and healthy individuals.
• To compare ILC1 and ILC2 populations and their ratio in asthma patients versus healthy controls following rhinovirus infection.

Main Methods:

• Moderate asthma patients and healthy subjects were inoculated with rhinovirus-16.
• Bronchoscopy was performed at baseline, Day 3, and Day 8 post-inoculation.
• Pulmonary ILC1 and ILC2 cells in bronchoalveolar lavage fluid were quantified using flow cytometry.

Main Results:

• Asthma patients exhibited higher baseline ILC2 levels compared to healthy subjects.
• Both groups showed increased ILC2s by Day 8, with significantly higher levels in asthma patients.
• Asthma patients had a higher ILC2:ILC1 ratio, correlating with exacerbation severity and type 2 cytokines.

Conclusions:

• An ILC2-predominant inflammatory profile in asthma patients is linked to more severe and prolonged rhinovirus infections.
• These findings support a role for ILC2s in the pathogenesis of virus-induced asthma exacerbations.
• Targeting ILC2s may offer a therapeutic strategy for managing virus-induced asthma exacerbations.