Cigarette smoke aggravates asthma by inducing memory-like type 3 innate lymphoid cells

Area of Science:

• Immunology
• Respiratory Medicine

Background:

• Cigarette smoking is a known asthma exacerbator, yet few studies focus on smokers.
• Asthma severity is linked to specific immune cell profiles.

Purpose of the Study:

• To investigate the impact of smoking on immune cell populations in asthma.
• To elucidate the role of innate lymphoid cells (ILC3) in smoking-related asthma exacerbation.

Main Methods:

• Comparison of sputum and blood samples from smoking and non-smoking asthma patients.
• In vitro exposure of innate lymphoid cells (ILCs) to cigarette smoke extract.
• Analysis of ILC3 frequencies, CD45RO expression, neutrophil counts, M1 alveolar macrophages, and airway epithelial barrier function.

Main Results:

• Smoking associated with higher frequencies of pro-inflammatory ILC3s in sputum and memory-like ILC3s in blood.
• ILC3 frequencies correlated with neutrophil counts and M1 alveolar macrophages, not eosinophils.
• Cigarette smoke extract induced CD45RO expression on ILC3s and impaired airway epithelial barrier function, increasing IL-1β production.

Conclusions:

• Cigarette smoking increases local and circulating activated ILC3 frequencies.
• Smoking contributes to ILC3 activation, exacerbating non-allergic asthma inflammation and severity.