All blood types contain the same basic components: red blood cells, white blood cells, platelets, and plasma ; However, proteins appear on the surface of red blood cells, markers called antigens that are grouped into eight basic blood types: A, B, AB, and O, with their corresponding “positive” or “negative” . Among them, the AB blood type is quite unique; in fact, it is the rarest blood group of all that exist.
“We inherit our blood groups in genes. The blood group gene encodes a protein that is expressed on the surface of red blood cells and is what is detected in the laboratory. Thus, what is expressed on the surface of the cell determines the blood type and if it is compatible with that of the patient “, comments Leslie Silberstein, from the American Society of Hematology.
Thanks to the German pathologist Karl Landsteiner (in the year 1900), who began to mix blood from different people, discovering that some mixtures were compatible and others were not, he marked a great milestone in medicine by identifying and typing the different blood groups, something that It earned him the Nobel Prize in Medicine and Physiology in 1930.
But why is it so difficult to find people with this blood type?
Basically because the red blood cells of this group have the two types of antigens: A and B; but the plasma does not have any antibodies. In blood group A we find the Anti-B antibody; in blood group B its plasma has Anti-A antibodies and in group 0 the red blood cells do not have antigens, but the plasma has Anti-A and Anti-B antibodies. The exception of group AB is therefore that its plasma does not have any antibodies.
Percentages
According to the Stanford School of Medicine (USA) the proportions among the general population would be as follows:
O-positive: 37.4%
Or negative: 6.6%
A positive: 35.7%
A negative: 6.3%
B-positive: 8.5%
B-negative: 1.5%
AB-positive: 3.4%
AB-negative: 0.6%
Curiosities of the blood
Blood group B is more common in Asians than Caucasians.
Group O is more common in Hispanics.
People with AB blood inherit an A gene from one parent and a B gene from the other parent. So the odds of that particular combination occurring are simply lower than any other possibility.
