Antiphospholipid antibodies and the protein C pathway.
Haemostasis is a delicate balance between procoagulant and anticoagulant processes. In the human body usually anticoagulant mechanisms prevail over procoagulant mechanisms, thereby preventing a prothrombotic state. The antiphospholipid syndrome is an example in which this balance is shifted to a more prothrombotic state due to the presence of antiphospholipid antibodies. One of the most extensively proposed pathogenic mechanisms within the antiphospholipid syndrome is the inhibition of protein C by antiphospholipid antibodies. Antiphospholipid antibodies have been described to have different actions on the protein C pathway, for example decreasing protein C and/or S plasma levels, inducing increased resistance against activated protein C and lowering thrombin levels (resulting in an impaired protein C activation). This review briefly discusses the actions of protein C in human body but mainly focuses on the effects of antiphospholipid antibodies on the protein C pathway that have been described in literature.
Urbanus
R T
RT
Department of Clinical Chemistry and Haematology, University Medical Center Utrecht, The Netherlands.
de Laat
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B
D017152:Antibodies, Antiphospholipid / Q000276:immunology*; D016736:Antiphospholipid Syndrome / Q000276:immunology / Q000503:physiopathology*; D001777:Blood Coagulation / Q000276:immunology; D006487:Hemostasis / Q000276:immunology; D006801:Humans; D011486:Protein C / Q000037:antagonists & inhibitors* / Q000276:immunology; D017293:Protein S / Q000276:immunology / Q000378:metabolism; D013917:Thrombin / Q000276:immunology / Q000378:metabolism
D017152:Antibodies, Antiphospholipid; D011486:Protein C; D017293:Protein S; D013917:Thrombin