Abstract
Factor XIa (F. XIa) is inactivated with either α1 antitrypsin (α1AT) or antithrombin III (AT III). To assess the contribution of α1 AT and AT III to the inactivation of F. XIa, we assayed F. XIa-α1AT complex and F. XIa-AT III complex in normal serum and in plasma of the patients with disseminated intravascular coagulation (DIC), in which F. XIa and plasma protease inhibitors were coexisting.
In serum, we could detect more F. XIa-AT III complex than F. XIa-α1AT complex. Next, we measured the levels of both complexes in the patients with DIC originated from various triggers. F. XIa-α1AT complex level was always higher than F. XIa-AT III complex level in each patient, irrespective of the administration of heparin and the levels of F. XI, α1AT and AT III.
These results indicated that the contribution of α1AT to the inactivation of F. XIa was greater than that of AT III in vivo.
