TISSUE FACTOR ANTIGEN LEVELS IN VARIOUS BIOLOGICAL-FLUIDS

Tissue factor (TF), a transmembrane surface protein, is known to initi ate thrombogenesis through plasmatic and cellular activation processes . Besides complexing with factor VII, eventually leading to fibrin gen eration via the extrinsic pathway, TF can also activate factor IX, res ulting in the intrinsic activation of coagulation. Other functions of TF are currently unknown, although various cells are believed to have TF receptors. Many of the post-surgical and post-interventional thromb otic events are due to the release of TF. Increased levels of TF are a ssociated with several pathologic conditions such as cancer, sepsis an d inflammation. Cellular necrosis also results in an increase of TF as the cells in the traumatized area lyse and release endogenous cell su rface-bound TF. An ELISA method (American Diagnostica, Greenwich, CT) has been developed to assay TF antigen levels in various biological fl uids. This ELISA employs a murine monoclonal antibody raised against n ative human TF for antigen capture. In this study, cerebrospinal fluid , peritoneal fluid, pleural effusion and urine from patients were assa yed for their TF content using this ELISA method. Normal individual se rum and plasma were also assayed as controls against which the levels of TF in the patients' body fluids could be compared. The amount of TF antigen in normal human plasma and serum was 165 +/- 139 pg/ml and 16 5 +/- 110 pg/ml, respectively. Concentrations of TF antigen in other f luids were: cerebrospinal fluid 868 +/- 721 pg/ml, peritoneal fluid 12 4 +/- 247 pg/ml, pleural effusion 385 +/- 569 pg/ml synovial fluid 97 +/- 23 pg/ml, seminal plasma 11485 +/- 875 pg/ml and urine 86 +/- 57 p g/ml. These results show that this ELISA-based assay is capable of qua ntitating levels of TF in various biological fluids. This method can a lso be used to detect the presence of TF in cell cultures, organ washe s, tissue exudates and extracts. Needle biopsies and body secretions m ay provide an additional diagnostic parameter in the assessment of var ious pathophysiologic disorders.