ABO blood group system roles in cell membrane integrity, cell adhesion, membrane transportation of molecules, and acting as receptors for extracellular ligands, and enzymes. ABO antigens are found having similar roles on epithelial cells as well as red blood cells. The ABO antigen is also expressed on the von Willebrand factor (vWF) glycoprotein, which participates in hemostasis (control of bleeding). In fact, having type O blood predisposes to bleeding, as 30% of the total genetic variation observed in plasma vWF is explained by the effect of the ABO blood group, and individuals with group O blood normally have significantly lower plasma levels of vWF
Human blood group systems three types of cells: The most common type of grouping is the ABO blood group system. The varieties of glycoprotein and glycolipid coating on red blood cells divides blood into four groups: Another antigen, the Rh factor, plays an important part in the grouping of blood. If this is present, the particular blood type is called Rh-positive. If it is absent, it is called Rh-negative. In addition to the ABO and Rh blood group systems, there are more than two hundred minor blood groups that can complicate blood transfusions. These are known as rare blood types. Whereas common blood types