You should know what blood types are!
Blood system antigens
The antigenic structure of the human body is incredibly complex. Only in the blood, modern science has discovered about five hundred antigens, combined into 40 antigenic systems: MNSs, AB0, Kell, Duffi, Luteran, Lewis and others.
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, it is cellular antigens (erythro-, thrombo- and leukocyte) that are of greater importance, since they are immunogenic (the ability to evoke an immune response), and therefore, when transfusing blood that is incompatible with respect to cellular antigens, there is a risk of developing hematogenous shock or DIC with lethal outcome. Blood antigens consist of two main parts: an antigenic determinant that determines immunogenicity, and a hapten that "weights" the antigen and determines serological activity.
The first partis highly specific for each antigen, and therefore distinguishes them from each other. Thus, in the AB0 system, antigen 0 is distinguished by fucose, antigen A by N-phcetylglucosamine, and antigen B by galactose. These determinants are joined by antibodies during the development of the immune response. These antigens are taken into account during blood transfusion, as well as when calculating the possible inheritance of a blood group.
AB0 system and its inheritance
Back in 1901, substances capable of sticking red blood cells together were found in human blood, which were called agglutinins (plasma agglutination factors - α and β) and agglutinogens (erythrocyte bonding factors - A and B).
According to this system, scientists J. Jansky 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 group I, but the plasma contains both agglutinins. Their blood is designated αβ or 0. People with blood type 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 type IV is distinguished by the presence of erythrocytes of both agglutinogens A and B (AB), while agglutinins are absent. 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 blood group proceeds equally. The blood type of the unborn child can always be assumed fromwith a probability of 100, 50 or 25% with different combinations of blood types of parents. Thus, knowing their antigens, the inheritance of the blood type of children can be traced according to 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 the knowledge of the Rh factor, since it is also important for the compatibility of blood types during transfusion. So, Rh-positive blood (Rh +) can be transfused to a patient with Rh-negative (Rh-) blood only once in a lifetime and as a last resort, since the first transfusion will produce Rh antibodies that are activated during the second transfusion (and the recipient risks dying from transfusion shock). The same applies to Rh-conflict when a fetus is conceived with Rh-positive blood in Rh + mother and Rh- father, so it is important to calculate the inheritance of the blood type of the unborn child.
