An Antitihaemophilic Globulin (Factor VIII) Inhibitor: Purification, Characterization and Reaction Kinetics

The Immunologic Character of Acquired Inhibitors of Antihemophilic Globulin (Factor VIII) and the Kinetics of Their Interaction with Factor VIII*

“…Temperature dependence of the present inhibitors is similar to that reported by others (9,12,13) although even at 7°C the rate of Factor VIII inactivation was appreciable. Leitner and his colleagues (13) remarked on the unusually great effect of temperature on the inhibitor Factor VIII reaction.…”

“…The nature of these inhibitors has not been clearly defined. Kinetic studies have led some investigators to conclude that Factor VIII is destroyed enzymatically (9), whereas others interpret their results to indicate stoichiometric inactivation (12,13). Chemical studies are consistent with the assumption that Factor VIII in-hibitors are antibodies (2,3,13), but, with one exception (14), direct evidence for their identification as immunoglobulins is lacking.…”

“…Inhibitory activity generally has been found in y-globulin-rich fractions isolated by ammonium sulfate precipitation (1, 13), alcohol fractionation (3,8,9), and electrophoresis (1,13,31,32) ; however, one patient has been reported in whom the electrophoretic y-globulin fraction was devoid of activity (10). A sedimentation constant of 7 S has been estimated by density gradient centrifugation in a single case (13), and a similar, or smaller, size can be inferred from the report of transplacental transfer of a circulating anticoagulant (33).…”

A circulating anticoagulant in gamma-1A-multiple myeloma: its modification by penicillin.

“…In a large number of subjects no basic disorder can be detected (1 hibitors differ in several respects from those seen in our patient. They are found chiefly in the /,-globulin fraction of the plasma (42)(43)(44). Incubation of normal and pathologic plasmas together accentuates the defect as incubation is prolonged (1,30).…”

Le rôle des inhibiteurs faibles du facteur VIII

“…L'unité d'inhibiteur du facteur VII sera, selon Bicgs et al [2,15], la quantité capable de neutraliser 75% du facteur V III contenu dans un ml de plasma.…”