To investigate the mechanism of OK-432 induced pleurodesis in carcinomatous pleuritis, we studied procoagulant activity (PCA) of mononuclear cells in pleural fluids. Five patients with primary lung cancer and carcinomatous pleuritis were studied. Before intrapleral administration of OK-432, pleural fluids and peripheral blood were taken and separated into mononuclear cells using Ficoll-Paque Method. Monouclear cells were incubated with several concentrations of OK-432 for twenty hours. PCA was measured using a one-stage coagulation assay. Mononuclear cells both in pleural fluids and in peripheral blood showed markedly increased PCA in a dose dependent manner. In two of five patients, PCA of mononuclear cells in pleural fluids after intrapleural administration of OK-432 was measured. Compared with PCA before intrapleural administration of OK-432, PCA after treatment was clearly augmented.
It was shown that OK-432 could augment PCA of mononuclear cells in pleural fluids both in vitro and in vivo. It was suspected that augmented PCA of mononuclear cells in pleural fluid might lead to fibrosis and adhesion of pleura.
