Elevated levels of thrombin-heparin cofactor II complex in plasma from patients with disseminated intravascular coagulation

An ELISA assay for quantitation of the thrombin-heparin cofactor II complex (T-HC II) in plasma was developed. Plasma was incubated with immobilized, specific antibodies to human thrombin. The second, biotinylated antibody was directed against human HC II. The assay was insensitive to thrombin-antithrombin complex (TAT) and to uncomplexed HC II. In plasma samples from 31 normal individuals (aged 21 - 68, mean 43.3 years), the T-HC II ranged 0.3 - 6.1 ng/ml; median 1.5, mean 2.0, and SD 1.6 ng/ml. In plasma samples from 13 patients with disseminated intravascular coagulation (DIC), T-HC II ranged 0.4 - 30.0 (median 13.5) ng/ml. In plasma samples from 6 patients in which the clinical suspicion of DIC was not verified, T-HC II complex ranged 1.4 - 14.3 (median 3.6) ng/ml. In plasma samples with elevated T-HC II levels, TAT was usually elevated, and on the average more than was T-HC II. These results indicate that HC II contributes significantly to the inactivation of in vivo generated thrombin.