Relationship of factor VIII to ristocetin-induced platelet aggregation; effect of heterologous and acquired factor VIII antibodies

• Published in: Thrombosis research Vol. 3; no. 4; pp. 363 - 373
• Main Authors: Thomson, C., Forbes, C.D., Prentice, C.R.M.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 1973
• ISSN: 0049-3848; 1879-2472
• DOI: 10.1016/0049-3848(73)90031-5

Platelet aggregation by ristocetin provides a means by which platelets from normal subjects and patients with von Willebrand's disease may be distinguished. We have measured ristocetin-induced platelet aggregation in von Willebrand's disease patients after infusion of cryo-precipitate and have found that improvement in platelet aggregation corresponded to levels of factor VIII-related antigen rather than factor VIII procoagulant activity. The normal response of platelets to ristocetin was lost when normal platelet rich plasma was incubated with either heterologous factor VIII antiserum or plasma from patients with acquired factor VIII inhibitors in high titre. The findings suggest that the acquired factor VIII inhibitors modify factor VIII-related antigen so that it no longer mediates platelet aggregation by ristocetin.