Thorax 1988;43:684-692 Number and activity of inflammatory cells in bronchoalveolar lavage fluid in asthma and their relation

Bronchial responsiveness to inhaled methacholine was measured four to six days before fibreoptic bronchoscopy in 22 asthmatic patients (10 smokers) and 20 control subjects (12 smokers). The asthmatic patients had a baseline FEV, greater than 60% predicted and a PD20FEV, (provocative dose of methacholine causing a 20% fall in FEV,) of 0 006-3-7 mg. The 20 control subjects had normal pulmonary function and a PD20FEV, above the maximum cumulative dose of methacholine of 6-4 mg. Bronchoalveolar lavage ofa middle lobe segment (lingula in four subjects) was performed with three sequential 60 ml aliquots of sterile saline. Cellular metabolic activity was stimulated with latex in aliquots of resuspended cells, and measured by means of luminol enhanced chemiluminescence to assess neutrophil activity and lucigenin enhanced chemiluminescence to assess macrophage activity. Mean absolute total cell counts were similar in the asthmatic and control groups but there were differences in differential cell counts, with a significant increase in eosinophil (p < 0 05) and lymphocyte (p < 0 05) counts in asthma. PD20FEV, was negatively correlated with percentage neutrophil counts (p < 0005). Luminol enhanced chemiluminescence/1000 neutrophils was increased about twofold in asthmatic subjects (p < 0 001), but was not correlated with PD20FEV1. Lucigenin enhanced chemiluminescence/1000 macrophages was increased nearly fourfold in asthmatic patients (p < 0-001) and showed a negative correlation with PD20FEV, (p < 0-01). The macrophage count was increased twofold in current smokers in both groups, but other cell numbers were not altered significantly. Smoking did not affect cellular metabolic activity in either group. This study supports the idea that an inflammatory process is present in the airways of those with asthma, and suggests a relation between bronchial responsiveness and both neutrophil numbers and macrophage activity.