Autoanti-Factor VIII Inhibitor and Acquired Hemophilia - Disseminated Intravascular Coagulation Flashcards
Specifically inhibit factors II (pro-thrombin), V, VIII, IX, and XIII and VWF have been described in nonhemophilic patients
Acquired autoantibodies
The most common auto-antifactor which is a diagnostic of acquired hemophilia
Factor VIII
Ocasionally associated with rheumatoid arthritis, inflammatory bowel disease, systemic lupus erythematosus, or lymphoproliferative disease
Acquired hemophilia
Lab result in Acquire Hemophilia:
PTT:
PT and TT:
PTT: Prolonged
PT and TT: Normal
This test confirm the presence of the inhibitor.
Clot-based mixing studies
The return of prolongation after incubation occurs because factor VIII autoantibodies are often of what immunoglobulin isotype?
G4 isotype
This inhibitors may immediately prolong the mixture’s PTT; in this case an incubated mixing study is unnecessary
High avidity inhibitors
Develop in 30% of patients with severe hemophilia in response to factor VIII concentrate therapy, exhibit type I kinetics.
Alloantibodies to Factor VIII
There is linear in vitro neutralization of factor VIII activity over 2 hours, which results in complete inactivation
Type 1 kinetics
T/F: Type II kinetics, the titration of inhibitor activity is semiquantitative
TRUE
Quantitation of autoanti-VIII inhibitor is accomplished using the __ which is ordinarily employed to measure inhibitors in hemophilic patients with alloantibodies to factor VIII
Nijmegen-Bethesda assay
Are used to follow the response to immunosuppressive therapy but are not needed for management of the bleeding symptoms
Repeat titers
Antibodies that prolong the PT
Antiprothrombin (Factor II) antibodies
Autoantibodies to factor V may arise spontaneously in auto-immune disorders and after exposure to
Bovine thrombin fibrin glue
Deficiency in amyloidosis may be caused by what seems to be an absorptive mechanism
Autoanti-factor X