Based on the type of antigen present on the surface of our red blood cells, we can determine the blood group to which each of our blood belongs.
There are numerous blood groups, although the most well-known and widespread are those that form the AB0 system: group A, group B, group 0 and group AB.
The letters A and B indicate the type of antigen present, that is a protein called agglutinogen which may be type A or type B, however, some subjects belong to the blood group AB, in this case they possess agglutinogens of both types.
The figure 0, on the other hand, indicates that in this blood group the red blood cells do not have any agglutinogen on the surface.
The discovery of blood groups was a revolutionary discovery by Karl Landsteiner in 1901, who later received the Nobel Prize.
This discovery has saved many lives thanks to the science of transfusions. When a transfusion is performed, it is necessary to check whether the blood groups of the donor (the one who gives blood) and the recipient (the one who receives) are compatible, because the blood that one person tolerates can be harmful to another, in fact, mixing incompatible blood groups can lead to very serious, often fatal consequences.
In the blood plasma it is possible to find the presence of proteins called agglutinins, we speak of antibodies anti A and antibodies anti B, with the task of destroying the red blood cells carrying the corresponding antigen, In fact, the agglutinin of the missing agglutinogen is always present.
If the blood groups of the donor and the recipient were incompatible, a molecule of agglutinin would bind to itself two or more red blood cells, giving rise to masses able to obstruct blood vessels, this phenomenon is called agglutination and there is a risk that it may endanger the life of the recipient.
When we talk about blood groups we must also refer to the factor Rhesus (Rh), discovered thanks to the studies done on the Rhesus Macaques, from which it takes name. The factor Rh is determined by the antigen D, also located on the surface of the red blood cells, moreover, depending on its presence the factor Rhesus is "positive" or "negative".
Now let’s see the compatible blood groups together:
an individual of group A+can donate blood to one of his group or to one of group AB+; an individual of group B+ can donate blood to one of his group or to one of group AB+; an individual of group 0+ may donate blood to all groups of the AB0 system, but may receive blood only from individuals of the same group and group 0-; an individual of group AB+ is called universal recipient, because it can only donate blood to individuals of its own group but it can receive blood from all others; an individual of group 0- can donate blood to all groups, in fact, is called universal donor, but can only receive it from individuals of its own group; an individual of group A- may donate blood to one of its own group or to one of group A-; an individual of group B- may donate blood to one of its own group, or to one of group B+, AB+, AB-; an individual of group AB- can donate blood to one of his own group or to one of group AB+.
Donating blood is a gesture of solidarity because in addition to helping those in need of blood for surgical operations, it also helps many people with blood diseases that need transfusions.
Mariacarla Frippa
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