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Research
by La Jolla Pharmaceutical Company
(Extracted
from latest release), for full report visit: http://www.ljpc.com/product_research_thrombosis.html
Delay in Factor Va inactivation
Activated by thrombin, Factor Va (5a) plays a key role in blood coagulation.
Factor Va acts as a co-factor to accelerate clot formation, giving rise to the
nickname "accelerin." Factor Va has a strong procoagulant effect, prolonging the
duration of clot formation. The inactivation of Factor Va is fundamental in
controlling the clotting process. Factor Va helps accelerate clotting in the
event of an injury, but Factor Va then needs to be rapidly inactivated by the
body to prevent the clot from expanding. In normal individuals Factor Va
generation and inactivation is regulated by activated protein C. It has been
proposed that anticardiolipin antibodies impair the normal functioning of
protein C.
Work in La Jolla Pharmaceutical Company laboratories has confirmed the observations of Galli, et al. (*1) that anticardiolipin antibodies
from APS patients can delay the inactivation of Factor Va, leading to a
prolongation of the clotting process. ACA can be isolated from patients, added
to normal human serum and the levels of Factor Va monitored over time. While in
the absence of ACA the normal serum levels of Factor Va rapidly return to
baseline after clotting is initiated, the presence of ACA causes the Factor Va
levels to remain elevated. At 20 minutes ACA from a typical patient cause the
levels of Factor Va to be 50% higher than normal. We believe that these
significantly higher levels of the procoagulant Factor Va may lead to an
increased tendency to form blood clots. Removal of the ACA by our Tolerance
Technology may correct the delay in Factor Va seen in APS patients and prevent
the inappropriate blood clot formation seen with these patients.
- Galli, M., Ruggeri, L., Barbui, T., Differential Effects of Anti-b2-Glycoprotein
I and Antiprothrombin Antibodies on the Anticoagulant Activity of Activated
Protein C . Blood, 1998, 91: No 6, 19992004.
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