Blood groups

Synonyms

Blood, blood group, blood types English: blood group

Definition

The term “blood groups” describes different compositions of glycolipids or proteins on the surface of the red blood cells (erythrocytes). These surface proteins act as antigens. For this reason, non-compatible foreign blood is recognized as foreign during transfusions and leads to the formation of so-called antigen-antibody complexes.

These clump together (agglutinate) and can thus lead to dangerous vascular occlusion. The composition of these surface components is hereditary and can therefore be used to clarify the relationship between the two. The ISBT (International Society for Blood Transfusion) distinguishes 29 different blood group systems. The most important are the AB0- and the Rhesus- system.

AB0 system

General The AB0 system of blood groups is the most important blood group system and comprises four groups: This system was established in 1901 by Karl Landsteiner. In 1930 he received the Nobel Prize for the discovery of the AB0 system. – A

  • B
  • AB and
  • 0

Function of the AB0 systemThe individual blood group types form different antigens on the surface of the red blood cells (erythrocytes).

This means that people with blood group A carry type A antigens, while blood group B carries type B antigens on the surface of the erythrocytes. People with blood group 0 do not carry antigens on the surface of the red blood cells, while blood group AB carries both antigen types. At the same time the body forms antibodies against the other surface components.

Thus, people with blood group A have antibodies against type B, while people with blood group B have antibodies against type A. People with blood group AB do not carry antibodies, whereas blood group 0 has both antibody types A and B. The reason for the formation of antibodies is bacteria that invade our body during the first year of life.

These carry similar surface structures to the erythrocytes and thus lead to the formation of antibodies when they are recognised as “foreign”. Blood groups A and B are inherited dominantly over group 0. Among each other, types A and B are codominant.

Type 0, on the other hand, is inherited recessively to A and B. Through this type of inheritance, blood group affiliation can be used to determine family relationships. Since blood groups A and B can carry genotypes AA and BB, respectively, as well as A0 and B0, respectively, it is more likely to carry one of these blood groups.

In contrast, persons with blood group 0 can only carry genotype 00 and persons with blood group AB can only carry genotype AB. ComplicationsThe formation of different antigens depending on the predominant blood group can lead to blood group incompatibility during blood transfusions. The reason for this is the formed antibodies against the “foreign” surface components of the erythrocytes.

Consequently, persons with blood group A must never receive blood from persons with blood group B, as this would lead to agglutination and thus blockage of all vessels. Furthermore, it can lead to the destruction of all erythrocytes, which can end in death. Since blood group AB does not produce any antigens, these persons can receive blood transfusions of all other blood groups.

Whereas people with blood group 0 can always be donors, but can only receive group 0 blood. FrequencyBlood groups A and 0 are the most common blood groups in the population. This applies not only to Germany, but also worldwide.

With 11% in Germany and 14% in Europe, blood group B is a rather rare blood group. However, by far the rarest group is AB. These carry only about 5% of the population in Germany, in Europe it is about 6.5%.