See also: Calculate blood type and blood group diet
The practice of blood transfusions was already in vogue in the old Europe of the seventeenth century. The first results, however, were disappointing, given that the transfusion was very often a real lethal poison for the patient. For this reason, before the end of the seventeenth century, this practice was banned from France and England.
In 1901 the studies of the Austrian Karl Landsteiner led him to discover the blood groups. This discovery, which earned him the Nobel Prize for medicine and physiology in 1930, revolutionized the belief that was at that time that blood was an identical tissue in all individuals.
In particular Landsteiner identified the presence of four different blood groups, which he named A, B, AB and 0. The reason for this differentiation was discovered later when the existence of the so-called erythrocyte antigens was noted.
What is a blood group?
When the organism is attacked by a pathogen (viruses, bacteria, etc.), it triggers a defense mechanism that attacks and neutralizes these antigens thanks to the presence of plasma proteins called antibodies.
On the surface of the red blood cells two different antigens can be distinguished: the antigen A and the antigen B. In the same way in the plasma anti-A antibodies and anti-B antibodies can exist. Both neutralize and kill red blood cells carrying the corresponding antigen. Based on this information:
anti-A antibodies and anti-B antibodies cannot coexist in an individual.
in an individual, erythrocyte type A antigens and anti-A antibodies cannot coexist
in an individual, type B erythrocyte antigens and anti-B antibodies cannot coexist
Each blood group is therefore characterized by the presence of specific antigens and the corresponding antibodies:
Group A contains A antigens and anti-B antibodies
group B contains B antigens and anti-A antibodies
the AB group contains antigens A, antigens B and none of the corresponding plasma antibodies
group 0 is antigen free but contains both anti-A and anti-B antibodies
Consequently:
the carrier of the AB blood group is the most fortunate given that, being devoid of specific antibodies, it can receive blood either from donors of type A, B, AB and 0 (universal receiver)
contrary speech for those with type 0 blood that can only receive similar blood (universal donor)
the individual of group A can instead receive blood from groups A and 0; while type B blood is compatible only with groups B and groups 0
If these combinations are not respected the antibodies present in the plasma (agglutinins) attack the red blood cells of the transfused blood, neutralizing them (agglutination reaction) and forming small lumps that occlude the blood vessels causing very serious damage to the body.
The blood group to which they belong is inherited from the parents and is immutable from birth to death. The frequency of these groups varies according to the ethnicity of the population: in England about 40% of individuals are in group A and only 10% are in group B; in India group A is present in 27% of cases and group B in 50%. Blood group AB is the rarest in Europe. |
The Rh factor ยป
