Table 1.

Alterations in the coagulation system in humans with SCD

Biochemical evidence of coagulation activationIncreased levelsDecreased levelsSteady stateAcute crisisReference
FXa generation
 Tissue factor pathway+++18, 68
 Intrinsic pathway (FXII, HMWK, prekallikrein)31, 32
Thrombin/fibrin generation
 Prothrombin fragment F1.2+++70
 Fibrinopeptide A+71
 Thrombin antithrombin complexes+++68
Changes in anticoagulant protein levels
 Protein C and S72, 73
 ATIII and heparin cofactor II74, 75
Changes in fibrinolytic protein levels
 Plasminogen activator inhibitor 1+++76, 77
Other plasmatic factors
Cellular factors contributing to coagulation
 Platelet number and size++*22
 Platelet activation and function+++80
 Red blood cell activation (PS exposure and adhesion)++81
 Leukocyte activation (TF exposure)+++20
 Endothelial activation (TF exposure and adhesion)+++17
 Cell-derived microparticles+++21
  • +, increased compared with controls; −, decreased compared with controls; ATIII, antithrombin III; FVIII, factor VIII; FXa, factor Xa; FXII, factor XII; HMWK, high-molecular-weight kininogen; PS, phosphatidylserine; TF, tissue factor; VWF, von Willebrand factor.

  • * Variable findings.