There are more than 300 blood group systems, and only one of them - AB0 - is the one that everyone knows about. There is also rhesus, "+" or "-". They are guided by them in everyday practice.
In boring language, the blood type is the antigenic profile of erythrocytes, and the blood type is the antigenic profile of plasma. What is "antigenic"? This word means association with the human immune system, i.e. an antigenic profile is an identification matrix, the "face" of something for immunity. It depends on whether this object will be perceived as foreign or not. If not, then everything is ok. If it is foreign, then it is destroyed (red blood cells stick together, clogging up blood vessels).
So, you cannot transfuse blood if the donor and recipient have different groups. That is, "B +" - only to "B +". Despite the fact that the blood may not coincide in the other ~ 300 systems (and this is practically unattainable), complications usually do not arise. If this main rule is violated, a person can die within a few minutes.
Human blood is a unique biomaterial, and the blood type remains the same throughout human life, just as eye color or fingerprints cannot change. Blood type is a sign that allows you to identify the identity of a person who is inherited by a child from his parents. The blood group is more ancient than the race, since the difference between the people of the planet is not at all in ethnicity, but in the composition of the blood. Knowing your own blood type is important because this information can save both your own life and the life of another. There are four blood groups. Since blood type determination has become ubiquitous, scientists have found that in the United States, 73% of residents have blood group 2, and Indians have 1 group. Residents of the center of Asia are mainly owners of 3 blood groups. Differences between groups and Rh factors The difference between blood groups lies in the presence on the membrane of erythrocytes of a special antigen - agglutinogen, whose function is to connect erythrocytes. Moreover, two types of antigens are distinguished and designated as A and B. According to the AB0 system, blood groups are designated depending on the presence of a particular antigen:
the first group is designated as 0, since there are no agglutinogens in it;
type A antigens are in the blood of the second group, therefore it is designated as A;
the third group contains type B agglutinogens, it is also labeled - B;
the fourth blood group has antigens of two types at once and is designated as AB.
Blood groups are distinguished by the presence in its composition of a special protein agglutinin. It also comes in two types - a and b:
the first group contains both types of agglutinin (a and b);
the second contains exclusively agglutinin b;
in the third is agglutinin a;
in the fourth group, both types of agglutinin are absent. In 1940, scientists Landsteiner and Wiener established that human blood may contain a protein (antigen), which was called the Rh factor. The Rh factor can be positive or negative. If the protein is present in erythrocytes, then the blood will be considered Rh positive and denoted Rh +. If the protein is absent, then the blood will be called Rh factor negative and marked as Rh-. The vast majority of people who have a positive Rh. Rhesus positive carriers are 85% of people on the planet, the remaining 15% are Rh negative. All these group differences play a significant role in blood transfusion. The ideal solution would be to transfuse the receiving person with blood of the same group and Rh factor. But even in this case, the possibility of incompatibility and complications is not excluded. It is forbidden to transfuse blood of different Rh factors, since there will be a Rh conflict. As for emergency cases, transfusion of the first group with a negative rhesus factor is allowedrum to people with other groups.