INFLAMMATORY CELL NUMBER AND MEDIATORS IN BRONCHOALVEOLAR LAVAGE FLUID AND PERIPHERAL-BLOOD IN SUBJECTS WITH ASTHMA WITH INCREASED NOCTURNAL AIRWAYS NARROWING

Background: Increased nocturnal airways narrowing (NAN) in asthma is t hought to occur as the result of intensification of inflammatory proce sses in the airways. In this study we investigated the presence of inf lammatory cells and mediators in bronchoalveolar lavage (BAL) fluid an d peripheral blood (PB) and assessed their relationship with the occur rence of increased NAN. Methods: BAL fluid and PB samples were assesse d at 16:00 and 04:00 hours, separated by 7 days or more, in eight nona topic healthy subjects (group 1) and 17 atopic subjects with asthma wh o were using inhaled bronchodilators only. The fatter subjects were pr ospectively assigned to groups with and without NAN, as defined by a m ean circadian peak expiratory flow variation of less than 15% (group 2 ) and 15% or more (group 3), respectively. Results: Significantly high er eosinophil numbers and inflammatory activation products (eosinophil cationic protein, eosinophil-derived neurotoxin, histamine) were foun d in BAL fluid and PB from subjects with asthma in comparison with con trol subjects. However; increased NAN was not generally associated wit h a circadian fluctuation in cell number and inflammatory mediators in BAL fluid and PB. No differences in inflammatory cell numbers existed that distinguished between groups 2 and 3. However, in group 3 signif icantly higher BAL prostaglandin D-2 levels (70 vs 24 pg/ml; range 28 to 102 vs 11 to 90 pg/ml; p = 0.04) and serum eosinophil cationic prot ein levels (17.6 vs 16.1 ng/ml; range, 6.3 to 17.5 vs 6.3 to 60.3 ng/m l; p = 0.03) at 16:00 hours were detected compared with group 2. Concl usions: Our findings suggest that increased NAN is more likely to occu r in subjects with asthma with ongoing increased cellular activation d uring the day.