Shortened endotoxin-activated clotting times in patients with carcinoma

Isolated human monocytes generate tissue factor when stimulated with endotoxins. This tissue factor generation provides a convenient marker of monocyte activation. Furthermore, the only circulating blood cell capable of generating large quantities of tissue factor is the monocyte. Therefore, the addition of endotoxin to citrated blood, and the determination of the recalcification times after incubation, yields a measure of monocyte activation. In order to determine whether monocyte activation as measured by this technique varies between patients with carcinoma and healthy volunteers, recalcification times were evaluated. The recalcification time and range for 19 healthy volunteers (controls) was 6.55 min (5.3-8.5) for the saline incubated sample and 5.69 min (4.6-7.2) for the endotoxin-activated sample. The results for 13 patients with carcinoma are 4.81 min (3.3-6.3) for the former and 3.17 min (2.0-4.3) for the latter. These results show that the longest recalcification time with endotoxin incubation for patients with carcinoma was lower than the lowest recalcification time in the control group. Whether this simple test can be of use in the diagnosis and monitoring of patients with carcinomas is currently being investigated.