increased L1134 metabolites and PGD2 in BAL fluid after methacholine challenge in asth-

ABSTRACT: The bronchoconstrictor potency of inhaled methacholine is widely used to assess airway responsiveness. However, evidence has accumulated that methacholine inhalation challenge may lead to an inflammatory response in the lower respiratory tract. We therefore compared cellular, leukotriene and prostanoid profiles in bronchoalveolar lavages (BAL) obtained five hours after methacholine challenge to control lavages without prior challenge. Eight subjects with asymptomatic to mild bronchial asthma and nine nonatopic healthy controls were enrolled in the study. Without prior challenge, the percentage of BAL eosinophils was higher in the asth-matic subjects ((mean±so), 1.1±0.9%) than in the control subjects (0.1±0.1 %. Leukotriene 8 4 (LT84), and its omega-oxidation products (20-0H-LTB4 and 20-COOH-LTB4) were the only leukotricnes detectable in the baseline BAL fluids in five of the eight a~thmatic patients. After methacholine challenge, no change in BAL cell profile occurred, but in the asthmatic patients, the total amounts of LTB4 and its omega-oxidation products rose from 0.52±0.50 ng·mi· • (pre-challenge) to 1.55±1.3