Summary
Platelet functions have been studied in relation to hemostasis in two patients with
congenital afibrinogenemia.
Neither in the plasma nor in the aqueous platelet extracts of these patients was fibrinogen
detectable by immunoelectrophoresis or with the aid of the Ouchterlony technique.
ADP-induced platelet aggregation, adhesion to connective tissue particles, viscous
metamorphosis under the influence of thrombin, clot retraction activity of the platelets,
as well as their factor 3 activity were all found normal. Abnormal was the behaviour
of the patient’s platelets on glass surfaces : they were unable to adhere to glass
and the typical spreading on such surfaces was equally missing. This defect was normalized
in vitro by the addition of small amounts of fibrinogen and correspondingly the patients
platelets showed normal adhesiveness after fibrinogen transfusions. Normal platelets,
suspended in afibrinogénémie plasma lost their adhesiveness toward glass surfaces.
After transfusion of Cohn fraction I the prolonged bleeding time of the patients was
normal and the clinical improvement presisted for a period of about 3 weeks, this
inspite of the fact, that no fibrinogen was detectable by the usual methods 10 days
after the transfusion.
The significance of these results as well as their implications for the role of fibrinogen
in hemostasis are discussed.
