Procoagulant activity of purified protein derivative-stimulated pleural effusion mononuclear cells in tuberculous pleurisy.

Mononuclear cells (MNC) generate cell-bound procoagulant activity (PCA) which shortens recalcification time after incubation with an antigen to which the donor has been sensitized. PCA has been demonstrated in various lung diseases, including exudative pleural effusions. To determine the value of measuring cell-bound PCA in the diagnosis of tuberculous pleural effusions we examined pleural effusion MNC of patients with tuberculosis (n = 19), congestive heart failure (n = 7), and carcinoma (n = 7). MNC were isolated, incubated in 0 or 10 micrograms/ml purified protein derivative (PPD) for 15 min and for 20 h, and recalcification time determined. Incubation with thromboplastin was used as control. The recalcification times in serum incubated for 15 min varied within a wide range, the mean values were longest for tuberculous effusion MNC, incubation for 20 h increased variation. Incubation of cells for 15 min with thromboplastin led to a decrease of mean recalcification time in tuberculous (p < 0.001) and heart failure (p < 0.05), and with no significance in carcinomatous effusions. Incubation with PPD led to decrease of recalcification time which was not significant. Comparisons of the mean relative recalcification times after PPD incubation showed that tuberculosis differed from lung cancer (p < 0.001), lung cancer from heart failure (p < 0.05), but not heart failure from tuberculosis. We conclude from our study that pleural effusion MNC express spontaneous PCA in vitro which is strongest in carcinomatous pleural effusions. Incubation of MNC with thromboplastin and less discernable with PPD leads to an increase in PCA which is more pronounced in tuberculous pleural effusions. However, due to substantial intersubject variability and overlap between the study groups, this test does not allow reliable differentiation of tuberculous from other MNC rich pleural effusions.