Thrombin Generating Capacity and Phenotypic Association in ABO Blood Groups

Area of Science:

• Hematology
• Biochemistry
• Genetics

Background:

• Individuals with blood group O have a higher risk of bleeding compared to non-O blood groups.
• Lower levels of coagulation Factor VIII (FVIII) and von Willebrand Factor (VWF) are observed in individuals with blood group O.
• The precise mechanisms linking blood group O to altered hemostasis require further elucidation.

Purpose of the Study:

• To investigate the relationship between ABO blood groups, thrombin generation (TG), prothrombin activation, and thrombin inactivation.
• To determine how blood group O influences key hemostatic factors and their functional impact.

Main Methods:

• Measured plasma levels of VWF, FVIII, antithrombin, fibrinogen, prothrombin, and alpha-2-macroglobulin (α2M) in 217 healthy donors.
• Assessed TG in platelet-rich plasma (PRP) and platelet-poor plasma (PPP).
• Calculated prothrombin conversion efficiency and thrombin decay capacity.

Main Results:

• Blood group O individuals showed lower VWF (75%) and FVIII (78%) levels, and higher α2M levels (125%).
• TG was 10% lower in the O group in both PRP and PPP.
• Prothrombin conversion was reduced (86%) and thrombin decay capacity was lower in the O group, with α2M playing a more significant inhibitory role (126%).

Conclusions:

• Thrombin generation is diminished in individuals with blood group O, primarily due to reduced prothrombin conversion and enhanced thrombin inactivation by α2M.
• The observed differences in TG are independent of platelet function, as TG was similar in PRP and PPP.
• Lower FVIII levels in blood group O individuals contribute to the decreased prothrombin conversion and subsequent higher bleeding risk.