General characteristic of system of ABO.

The system of antigens of ABO is made by three antigens: A,B and O, which, except erythrocytes, are available in leucocytes, thrombocytes, fabric cells and plasma.

Two natural antibodies – agglutinins α (anti-A) and β belong to this antigenic system (anti-B). Agglutinin α connects only to an antigen A, and agglutinin β – only with B. Genetic's antigen 6 combinations of allelic antigens – 00, A0, AA, B0, BB, AB are possible.

As the hetero - and homozygous options of combinations of antigens (A0 and AA, B0 and BB) are included into one group, allocate four main blood types: Oαβ (I) – the first, Aβ (II) – the second, Bα (III) – the third and AB0(IV) – the fourth.

In our country and in the majority of other countries alphanumeric designation of blood types is accepted: O (I), A(II), B (III), AB (IV).

The antigen A is an independent weak antigen. It is taped only by special Serums and its practical value is small.

The antigen A is presented by several versions from A1 to. Absolute number of people of the II blood type have A1 antigen (approximately at 88%), A2 antigen meets (to 12%) less often.

In the presence of an agglutinogen of A1 it is designated as A, and the index is used only for A2. In transfuziology practice only antigens of A1 and A2 and according to it subgroups of a blood of A and A2, AB and A2B matter.

Persons with subgroups of a blood of A(II) can have seldom found α2 extraagglyutinina [A (II) bα2 and AB (IV) α2], and with subgroup of A2 – α1 [A2 (II)bα1 and A2B (IV) α1]. At a hemotransfusion, eritromassa are guided by the principle of transfusion only of an odnogruppny blood. However in an exclusive situation, so far as concerns conservation of life of the patient, transfusion of an inogruppny blood (at children of it it is impossible to do) is possible.

(The universal donor of O(I) Rh-negative) people can pour in the first blood type in emergency situation with other blood type if there is no one group blood or not time for definition of its group. The hemotransfusion of the universal donor is carried out only driply that agglutinins got divorced in a blood of the recipient.

In a critical situation people of AB (IV) of a blood type (the universal recipient) can pour in any other blood.

The other group blood is entered only for a hemorrhage restore of no more than 500 ml.

It corresponds to the direct rule of Ottenberg: at transfusion of small doses of a blood (to 500 ml) agglutinogens of the transfused blood since they are exposed to agglutination are considered.

At transfusion of high doses of a blood the poured agglutinogens and agglutinins (the return rule of Ottenberg) since the amount of agglutinins an and b will be sufficient not only for binding of water-soluble antigens A,B, but also for agglutination of own erythrocytes of the patient A, B, and AB are considered.

The universal donor, immunization on erythrocyte antigens, or the having congenital high caption of natural agglutinins, is considered the dangerous universal donor, and transfusion of such blood causes a hemolysis of erythrocytes of the recipient.

The universal recipient, immunization on any erythrocyte antigen, is considered the dangerous universal recipient and it can't transfuse an other group blood.

The "Bombay" type of a blood for the first time described at one of residents of Bombay is infrequent. In this case in erythrocytes there are no antigens A,B and O (true "zero"), and in Serums there are agglutinins a, b and the Anti-lake. Recipients with such group can transfuse only a blood of the "Bombay" type.

In transfusiology there is a rule: any "non-standard" blood of the donor for a hemotransfusion is unsuitable!

Дата добавления: 2015-10-29