RT Journal Article SR Electronic T1 The distribution of myeloperoxidase, eosinophil cationic protein, albumin and urea in sequential bronchoalveolar lavage JF European Respiratory Journal JO Eur Respir J FD European Respiratory Society SP 517 OP 523 DO 10.1183/09031936.93.04050517 VO 4 IS 5 A1 B Schmekel A1 P Venge YR 1991 UL http://erj.ersjournals.com/content/4/5/517.abstract AB The distribution of myeloperoxidase (MPO) and eosinophil cationic protein (ECP), secreted from activated neutrophils and eosinophils, was estimated in bronchoalveolar lavage fluid in a sequential lavage study performed on 12 healthy subjects. Four 50 ml aliquots were sequentially injected into the right middle lobe and immediately aspirated. Recent studies, using radiological methods, have revealed proximal airway distribution of the first infused lavage aliquot, and more peripheral distribution of the following ones. We found significantly higher concentrations of MPO (p less than 0.001) and ECP (p less than 0.001) in the first aspirated aliquots as compared to the following three. These findings are compatible with the concept that these substances are, to a substantial part, distributed to the surface of the proximal airways. In contrast, the sequential recovery of albumin and urea showed a homogeneous recovery pattern. The findings were compatible with those of a small series of sixteen 10 ml lavage aliquots, sequentially infused and aspirated, also indicating a continuous diffusion of these small molecules through the lung membranes into the lavage fluid during the lavage process. We conclude that the difference in recovery pattern and distribution on the bronchial surface makes albumin and urea unsuitable as denominators in ratios to MPO and ECP, for the estimation of quantitative local concentration in epithelial lining fluid.