RT Journal Article
SR Electronic
T1 Procoagulant (thromboplastin) activity in human bronchoalveolar lavage fluids is derived from alveolar macrophages
JF European Respiratory Journal
JO Eur Respir J
FD European Respiratory Society
SP 61
OP 67
DO 10.1183/09031936.93.03010061
VO 3
IS 1
A1 T Lyberg
A1 B Nakstad
A1 O Hetland
A1 NP Boye
YR 1990
UL http://erj.ersjournals.com/content/3/1/61.abstract
AB Fibrin deposition in the alveolar space and the lung interstitium is a prominent feature of many types of inflammatory pulmonary diseases. Cells of the monocyte/macrophage line are the primary cells supplying procoagulant activity in inflammatory lesions. In the present study we found that both lung alveolar macrophages (LAM) and bronchoalveolar lavage fluids (BALF) from humans contained procoagulant activities. The procoagulant in BALF was associated with membrane vesicles which sedimented at 100,000 g for 1 h. By electron microscopy the BALF ultrasediment was seen to consist almost exclusively of membrane material and this was confirmed by monitoring the content of different marker enzymes for specific subcellular structures. Using macrophage membrane markers, at least part of the BALF-ultrasediment was shown to be derived from LAM. On the basis of phospholipase C sensitivity, antibody neutralization and the site of action of the procoagulant in the sequential activation of coagulation factors, both the LAM-associated and the BALF-associated procoagulant activity was identified as thromboplastin (tissue factor) or thromboplastin-factor VII complexes. This suggests that alveolar macrophages and the LAM-derived thromboplastin-containing microvesicles may contribute to intraalveolar and interstitial fibrin deposition in vivo and probably also have consequences for the development of pulmonary fibrosis.