The American review of respiratory disease
-
Am. Rev. Respir. Dis. · Jun 1988
Regulation of the procoagulant activity within the bronchoalveolar compartment of normal human lung.
The nature of the procoagulant activity of normal bronchoalveolar fluid was examined both qualitatively and quantitatively. Unconcentrated, cell-free lavage freshly obtained from normal volunteers clotted normal plasma in a mean of 84 +/- 20 s. The procoagulant activity was initiated by Factor VII-tissue factor complexes as judged by differential activity in various plasmas genetically deficient in single clotting factors, by neutralization of the procoagulant activity with antibodies to either Factor VII or tissue factor, and by a Factor X activation assay. ⋯ When lavage and diluted plasma were adjusted to yield equivalent amidolytic activities, the average ratio of the Factor VII-clotting activity of the alveolar fluid relative to plasma Factor VII was 19 +/- 7, suggesting the presence of Factor VIIa in lavage. In contrast to previous reports with serum or activated plasma, immunoblots of concentrated lavage revealed only single-chain Factor VII, and 125I-Factor VII added to the fluid was not converted to 125I-Factor VIIa, suggesting a unique control mechanism in the lung compartment which differs from plasma. When equivalent Factor VII amidolytic activities in diluted plasma and cell-free lavage were compared, the rates of Factor Xa formation were very similar.(ABSTRACT TRUNCATED AT 250 WORDS)