Leukotrienes (LTs) C4 and B4 are potent proinflammatory mediators with a wide variety of biologic activities, including smooth muscle contraction, mucus hypersecretion, and leukocyte activation, which may be of particular relevance to the pathology of
asthma and other
respiratory diseases. We measured the concentrations of
LTC4 and
LTB4 in bronchoalveolar lavage fluid from 16 atopic subjects with
asthma (eight symptomatic and eight asymptomatic) and from 14 control subjects without
asthma (six with
hay fever and eight nonatopic). The amounts detected in symptomatic subjects with
asthma were significantly higher than in control subjects (
LTB4, 0.58 +/- 0.06 versus 0.36 +/- 0.05 pmol/ml, p less than 0.05;
LTC4, 0.36 +/- 0.1 versus 0.12 +/- 0.02 pmol/ml, p less than 0.01).
LTC4 and
LTB4 were also measured in 17 patients: nine with
interstitial lung disease of varying etiology (
cryptogenic fibrosing alveolitis [CFA] or
idiopathic pulmonary fibrosis), three with
sarcoidosis, one with
extrinsic allergic alveolitis, one with sulphonamide-induced
pneumonia, and one patient with
eosinophilic granuloma. The concentrations of
LTB4 (but not
LTC4) were significantly greater in patients with CFA compared with normal control subjects (0.69 +/- 0.3 versus 0.36 +/- 0.05 pmol/ml, p less than 0.01). There was a significant correlation (p less than 0.05) between the percentage of neutrophils and the concentration of
LTB4 in the bronchoalveolar lavage fluid) of the group with
interstitial lung disease as a whole. This study provides evidence for a role for LTs in the airways of subjects with day-to-day
asthma and suggests that
LTB4 may also be involved in the recruitment of granulocytes into the lung in patients with CFA.