부산대학교 도서관

We developed an assay for activated factor XI-α1antitrypsin complex (F. XIa-α1AT) in plasma. Purified F. XI was activated with β-XIIa and treated with α1AT. Thus we prepared the standard F. XIa-α1AT. Assay for F. XIa-α1AT was carried out essentially according to the method of Harpel. F. XIa-α1AT in sample plasma (10-fold dilution, 200μl) was adsorbed on anti-F. XI monoclonal antibody beads and developed with peroxidase-labeled anti-α1AT Fab'.To eliminate the effect of plasma on this assay, standard F. XIa-α1AT was diluted with 10% F. XI-deficient plasma which did not contain the complex. The absorbance of the standard complex containing F. XI (0.016-0.12μg/assay, i. e. 20-150%) was a little lower than that of the complex alone, because F. XI compete the binding of F. XIa-α1AT to the beads. Either F. XI or α1AT alone did not increase the color development. Therefore we diluted the standard F. XIa-α1AT with 10% F. XI-deficient plasma containing F. XI (0.08μg/assay, i. e. 100%). Recovery of added F. XIa-α1AT was satisfactory (over 90%).25 normal individuals had low level of F. XIa-α1AT (below 0.18ng/assay), whereas 30 patients with disseminated intravascular coagulation (DIC) demonstrated high level of this complex (0.18-4.2ng/assay). These data indicated that this assay was useful to the diagnosis of DIC.