What blood groups are, you should know!
Blood system antigens
The antigenic structure of the human body is incredibly complex. In the blood alone, modern science has discovered about five hundred antigens combined into 40 antigenic systems: MNSs, AB0, Kell, Duffi, Luteran, Lewis, etc.
Each of the antigens of these systems is genetically encoded and inherited by allelic genes. For simplicity, they are all divided into plasma and cellular. For hematology and transfusiology, cellular antigens (erythro-, thrombotic, and leukocyte) antigens are of greater importance, since they have immunogenicity (the ability to provoke an immune response), and therefore, when transfusion is incompatible with cellular antigens of the blood, there is a risk of developing hematogenous shock or DIC fatal. Blood antigens consist of two main parts: an antigenic determinant that determines immunogenicity, and a hapten, which “aggravates” the antigen and determines serological activity.
The first part is highly specific for each antigen, and therefore distinguishes them from each other. So, in the AB0 system, antigen 0 is distinguished by fucose, antigen A by N-acetylglucosamine, and antigen B by galactose. Antibodies are added to these determinants during the development of the immune response. These antigens are taken into account during blood transfusion, as well as when the possible inheritance of a blood group is calculated.
System AB0 and its inheritance
Back in 1901, substances capable of gluing red blood cells together were discovered in human blood, which were called agglutinins (plasma agglutination factors - α and β) and agglutinogens (erythrocyte adhesion factors - A and B).
According to this system, scientists Y. Yansky and K. Landsteiner divided all people into 4 groups, they also calculated the inheritance of blood groups in humans. So, people who have no agglutinogens in their blood have blood type I, but plasma contains both agglutinins. Their blood is designated αβ or 0. People with
blood group II have agglutinogen A and agglutinin β (Aβ or A0), people with group III, on the contrary, have agglutinogen B and agglutinin α (Bα or B0), and blood group IV is distinguished by erythrocytes of both agglutinogens A and B (AB), with no agglutinins. They are determined by a simple laboratory method using special standard sera. Since both agglutinogens are dominant, the inheritance of one of the antigens, i.e. inheritance of a blood group proceeds equally. The blood group of the unborn child can always be assumed with a probability of 100, 50 or 25% with different combinations of blood groups of the parents. Thus, knowing their antigens, the inheritance
of the blood type of children can be traced in the following table.
| Blood type | Father |
| Mothers | I (00) | II (A0) | II (AA) | III (B0) | III (BB) | IV (AB) |
| I (00) | 00 - 100% | 00 - 50%
A0 - 50% | A0 - 100% | 00 - 50%
B0 - 50% | B0 - 100% | A0 - 50%
B0 - 50% |
| II (A0) | 00 - 50%
A0 - 50% | 00 - 25%
A0 - 50%
AA - 25% | AA - 50%
A0 - 50% | 00 - 25%
A0 - 25%
B0 - 25%
AB - 25% | AB - 50%
B0 - 50% | AA - 25%
A0 - 25%
B0 - 25%
AB - 25% |
| II (AA) | A0 - 100% | AA - 50%
A0 - 50% | AA - 100% | AB - 50%
A0 - 50% | AB - 100% | AA - 50%
AB - 50% |
| III (B0) | 00 - 50%
B0 - 50% | 00 - 25%
A0 - 25%
B0 - 25%
AB - 25% | AB - 50%
A0 - 50% | 00 - 25%
B0 - 50%
BB - 25% | BB - 50%
B0 - 50% | A0 - 25%
B0 - 25%
BB - 25%
AB - 25% |
| III (BB) | B0 - 100% | AB - 50%
B0 - 50% | AB - 100% | BB - 50%
B0 - 50% | BB - 100% | AB - 50%
BB - 50% |
| IV (AB) | A0 - 50%
B0 - 50% | AA - 25%
A0 - 25%
B0 - 25%
AB - 25% | AA - 50%
AB - 50% | A0 - 25%
B0 - 25%
BB - 25%
AB - 25% | AB - 50%
BB - 50% | AA - 25%
BB - 25%
AB - 50% |
No less important is knowledge of the Rh factor, since it is also important for the compatibility of blood groups during transfusion. So, Rh-positive blood (Rh +) can be transfused to a patient with Rh-negative (Rh-) blood only once in a lifetime, and in the worst case, since the first transfusion will produce Rh antibodies that are activated during the second transfusion (and the recipient risks dying from blood transfusion shock). The same applies to the Rh conflict during the conception of a fetus with Rh positive blood in the Rh + mother and Rh-father, therefore it is so important to calculate the inheritance of the blood group of the unborn child.