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Airways inflammation in nocturnal asthma.
R J Martin1, L C Cicutto, H R Smith
1Department of Medicine, National Jewish Center for Immunology and Respiratory Medicine, Denver, CO 80206.
The American Review of Respiratory Disease
|February 1, 1991
Summary
Nocturnal asthma involves increased airway inflammation overnight, particularly with neutrophils and eosinophils. This cellular response correlates with worsening lung function, suggesting a key role in nocturnal asthma development.
Area of Science:
- Pulmonary Medicine
- Immunology
- Respiratory Physiology
Background:
- Nocturnal asthma is a common and disruptive condition.
- The underlying mechanisms driving nighttime asthma exacerbations remain poorly understood.
- Airway inflammation is a hallmark of asthma, but its temporal relationship with nocturnal symptoms is unclear.
Purpose of the Study:
- To investigate the presence and nature of airway inflammation during the night in patients with nocturnal asthma.
- To compare inflammatory markers in bronchoalveolar lavage fluid between asthmatic patients with and without nocturnal symptoms.
- To explore the correlation between changes in cellular components and overnight decline in lung function.
Main Methods:
- Bronchoalveolar lavage (BAL) was performed on two groups of asthmatic patients (n=7 each): those with and without nocturnal asthma.
- BAL fluid was analyzed at two time points: 1600 h (4 PM) and 0400 h (4 AM).
- Cellular counts, including leukocytes, neutrophils, eosinophils, lymphocytes, and epithelial cells, were quantified. Peak expiratory flow rates (PEFR) were also measured overnight.
Main Results:
- Patients with nocturnal asthma showed a significant increase in total leukocytes, neutrophils, and eosinophils from evening to early morning.
- The non-nocturnal asthma group did not exhibit significant changes in cellular components overnight.
- At 0400 h, the nocturnal asthma group had significantly higher counts of leukocytes, neutrophils, eosinophils, lymphocytes, and epithelial cells compared to the non-nocturnal group.
- The overnight decrease in PEFR was positively correlated with increases in neutrophils (r=0.54) and eosinophils (r=0.77).
Conclusions:
- Nocturnal worsening of asthma is associated with a distinct cellular inflammatory response in the airways.
- This overnight inflammatory process, potentially involving epithelial damage, appears crucial in the pathophysiology of nocturnal asthma.
- The findings highlight the importance of addressing nighttime airway inflammation for managing nocturnal asthma effectively.