Microvesicle-associated tissue factor and Trousseau's syndrome

Abstract

Background: Trousseau's syndrome is a prothrombotic state associated with malignancy that is poorly understood pathophysiologically.

Methods and results: Here we report studies on the blood of a 55-year-old man with giant-cell lung carcinoma who developed a severe form of Trousseau's syndrome. His clinical course was dominated by an extremely hypercoagulable state. Despite receiving potent antithrombotic therapy, he suffered eleven major arterial and venous thrombotic events over a 5 month period. We examined the patient's blood for tissue factor (TF), the major initiator of coagulation, and found its concentration in his plasma to be forty-one-fold higher than the mean concentration derived from testing of 16 normal individuals.

Conclusion: Almost all of the TF in the patient's plasma was associated with cell-derived microvesicles, likely shed by the cancer cells.

Fig. 1

Tissue factor (TF) levels in plasma. Using enzyme-linked immunoassay, we measured TF antigen in the cell-free plasma of 16 healthy men and in that of the patient. Panel A shows the plasma level of TF in healthy subjects and in the patient. The horizontal bar indicates the mean value for the normal group. Panel B shows the distribution of TF in the patient’s plasma. The plasma was centrifuged (200 000 g × 5 h), and the TF levels were measured in the upper and lower halves of the supernatant (Sup), and in the microvesicle (MV) pellet at the bottom of the tube. Almost all of the TF localized to the MV fraction. The flow cytometry dot plot in Panel C shows the MV counts in the control and patient’s plasma, each dot representing a single annexin-V-positive microvesicle. The plasmas were diluted 1:5 in buffer, and the number of microvesicles was counted over 150 s.

Fig. 2

Tissue factor (TF)-VIIa activity and tissue factor pathway inhibitor (TFPI) levels in plasma. Panel A shows the TF-VIIa activity in the plasma of controls and of the patient, measured using a chromogenic assay. Whereas treatment of the patient’s plasma with a control IgG had no effect on the TF-VII activity, an anti-TF monoclonal antibody markedly decreased it. The addition of anti-TF antibody to normal plasma had no significant effect on its TF-VIIa activity. Panel B shows the plasma levels of TF pathway inhibitor antigen in controls and in the patient. The horizontal bar indicates the mean value.

Fig. 3

Tissue factor (TF) in a mediastinal lymph node with metastasis. During the autopsy of the patient, a mediastinal lymph node with a metastasic tumor was obtained. Panel A shows metastatic giant-cell lung carcinoma cells stained with hematoxylin and eosin. Panel B shows that the cancerous cells immunostained intensely (seen as a brownish color) with an anti-TF rabbit polyclonal antibody. As shown in panel C, the TF signal observed was specific because non-immune rabbit IgG gave very little background staining.