|Disease||Blood clotting disorders|
|Blood Group Link||Blood type influences one of the more important clotting factors, called Factor VIII. Studies dating back to the 1960s have repeatedly shown that a deficiency of this important clotting factor is linked to Blood Type O, while Blood Type A and Blood Type AB have higher than average amounts. Blood Type B has an average amount. As a result, the blood of Type A and Type AB will clot more readily than the blood of Type O or Type B.|
Unlike the other factors, Factor VIII is not an enzyme. Factor VIII normally circulates in the plasma bound to von Willebrand factor. When thrombin is activated by injury to the vessel wall, it chops Factor VIII free from von Willebrand factor, and activates it. Von Willebrand factor goes on to bind to the ruptured blood vessel surface, where it stimulates platelets to stick together. Active Factor VIII (now called Factor VIIIa) reacts with another factor (Factor IXa), and calcium to help localize the site of clot formation to the injured vessel.
High levels of Factor VIII have been linked to coronary artery disease, and this may in part explain why coronary artery disease shows a higher rate of occurrence in Type A and Type AB. For example, there is evidence that hemophiliacs experience less coronary artery disease than expected, so high Factor VIII levels may contribute to the incidence of coronary artery disease by increasing one∆s potential for developing blood clots.
ABH non-secretors are reported to have shorter bleeding times and a tendency towards higher factor VIII and vWf. This relationship appears to be another example of blood type synergy between ABO and Secretor/Non-secretor phenotypes. In fact, secretor genetics appear to interact with ABO genetics to influence as much as 60% of the variance of the plasma concentration of vWf, with secretors (Le (a- b+)) having the lowest vWf concentrations. (1,2)
Among persons belonging to blood group O (the blood type most likely to have problems with clotting), the lowest concentration of vWf:Ag and VIII:Ag is found in the group O secretors. While blood group O non-secretors will have a higher concentration of both vWf:Ag and factor VIII antigen (VIII:Ag), providing them with a better capability for clotting. (3)
Based upon this research, researchers have suggested that the Le (a-b-) phenotype (and blood groups A, B, and AB especially), by virtue of their association with raised levels of factor VIII and von Willebrand factor, might be at a higher risk for future thrombotic and heart disease. (4)
A study at St. Bartholomew's Hospital, London linked the relationship between blood type, Factor VIII activity, von Willebrand factor antigen and ischaemic heart disease in 1393 men aged between 40 and 64 years. The incidence of heart disease was significantly higher in those of blood group AB than in those of groups O, A or B, particularly for fatal events. In addition, they theorized that blood type AB may be a genetic marker of characteristics influencing other risks for heart disease such as short stature, as the type AB men studied were about 2 cm shorter than those of other groups. (5)
+ Measurements of von Willebrand factor antigen and Factor VIII in a group of 40 blood donors (20 type O, 20 type A) showed reduced levels of both clotting factors in the blood type O as compared with the other blod types. The data suggests an influence of blood group antigens on the interaction between von Willebrand's factor and platelets. (6)
+ A study looking at pairs of twins showed that the concentration of Factor VIII was lowest in type O individuals, higher in A2 individuals, and highest in A1 and B individuals. The authors concluded that "Thirty percent of the genetic variance of VIII was due to the effect of ABO blood type. The ABO locus is therefore a major locus for the determination of factor VIII concentration." (7)
+ Blood group ABO antigens are known to be carried by glycoproteins found on platelets. Besides these proteins, blood group A antigen was also expressed on other platelet proteins as well. (8,9) Thus it appears that the genetic expression of blood type in blood type A individuals has some intimate effect on the function of their platelets.
To investigate possible associations between ABO blood system and coagulability levels, fibrinolysis, total lipids, cholesterol, and triglycerides, the plasma and serum of 300 Rh-positive male blood donors were tested. The tests performed were: RT, PTT, K-PTT, PT, F.V, F.II, F.VII, Complex II, VII, and X, TGT, fibrinogen, HAE 0.2, HAE 0.5, ELT, LIP, Col.1, Col.2 and TRI. Analysis of the laboratory data shows a lower coagulability in O blood group individuals. This result was obtained in coagulation tests (RT, PTT, and K-PTT) specific for factor VIII level. In addition, a higher sensitivity to the in vitro heparin anticoagulant effect in O group individuals was confirmed. Nevertheless, these conclusions are specific for Negroids, the same effects not being observed in Caucasians. None of the other laboratory tests revealed any differences related to either blood group or race.
In white men with blood groups A, B, or AB, and the Le(a-b-) phenotype, significantly higher levels of factor VIII (p < 0.01) and von Willebrand factor (p < 0.03) were observed than in those with other Lewis phenotypes (Le[a+b-] or Le[a-b+]). Two-way analysis of variance indicated a significant interaction between blood group and Lewis phenotype (p = 0.0053) in terms of relationship to factor VIII. A similar trend was observed in black men with blood type A, B, or AB, and phenotype Le(a-b-) for factor VII/von Willebrand factor and in women with blood type A, B, or AB, and phenotype Le(a-b-) for factor VIII. Our data suggest that the Le(a-b-) phenotype and blood groups A, B, and AB, by virtue of their association with raised levels of factor VIII and von Willebrand factor, may be risk markers for future atherothrombotic disease. (9)
|Special Note||Blood type and rheology|
Rheology is the science of deformation and flow. One common factor between solids, liquids, and all materials whose behavior is intermediate between solids and liquid is that if we apply a stress or load on any of them they will deform or strain. For our purposes we will use the term to describe the dynamics between blood clotting (moving towards a solid state) or blood thinning (moving towards a liquid state). It might be tempting to substitute the word 'viscosity' for rheology when talking about blood types and clotting, but it does not cover the 'dynamics' of how, when and why blood can change texture; it only distinguishes one texture state form another. As we will see, your blood type has a very potent effect on the rheology of your blood.
As we will discover, there are profound differences between the blood types with regard to rheology of their clotting chemistries. These differences are very significant reasons why the blood types tend to polarize with regard to their tendencies, with more blood types A and AB having much more easily clotting blood, and type O and B having blood which does not clot as readily.
Differences between the blood types in blood thickness have been also reported in depression (66) high blood pressure, (67) stress, (68) diabetes, (69) heart attack and thyroid disease, (70) kidney failure (71) and malignant melanoma. (72)
|References||1. Wahlberg TB, Blomback M, Magnusson D. Influence of sex, blood group, secretor character, smoking habits, acetylsalicylic acid, oral contraceptives, fasting and general health state on blood coagulation variables in randomly selected young adults. Haemostasis 1984;14(4):312-9|
2. Orstavik KH. Genetics of plasma concentration of von Willebrand factor. Folia Haematol Int Mag Klin Morphol Blutforsch 1990;117(4):527-31
3. Orstavik KH, Kornstad L, Reisner H, Berg K. Possible effect of secretor locus on plasma concentration of factor VIII and von Willebrand factor. Blood 1989 Mar;73(4):990-3
4. Green D, Jarrett O, Ruth KJ, Folsom AR, Liu K. Relationship among Lewis phenotype, clotting factors, and other cardiovascular risk factors in young adults. J Lab Clin Med 1995 Mar;125(3):334-339
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14. Dintenfass L, et al Effect of fibrinogen on aggregation of red cells and on apparent viscosity of artificial thrombi in haemophilia, myocardial infarction, thyroid disease, cancer and control systems: effect of ABO blood groups. Microvasc Res. 1975 Jan;9(1):107-18.
15. Dintenfass L, et al . Formation, consistency and degradation of artificial thrombi in severe renal failure. Effect of ABO blood groups. Thromb Diath Haemorrh. 1968 Nov 15;20(1):267-84.
16. Dintenfass L. Some aspects of haemorrheology of metastasis in malignant melanoma. Haematologia (Budap). 1977;11(3-4):301-7.
17. Huraux C, Ankri A A, Eyraud D, Sevin O, Menegaux F, Coriat P, Samama CM. Hemostatic Changes in Patients Receiving Hydroxyethyl Starch: The Influence of ABO Blood Group. Anesth Analg. 2001 Jun;92(6):1396-1401.
18. Hum Genet 1979 Apr 27;48(2):221-230 Investigation of associations between ABO blood groups and coagulation, fibrinolysis, total lipids, cholesterol, and triglycerides. Colonia VJ, Roisenberg I
19. J Lab Clin Med 1995 Mar;125(3):334-339 Relationship among Lewis phenotype, clotting factors, and other cardiovascular risk factors in young adults. Green D, Jarrett O, Ruth KJ, Folsom AR, Liu K