Hemagglutination

HEMAGGLUTINATION, agglutination (clumping) of red blood cells when mixed with homologous sera. If human red blood cells are mixed with the serum of the same individual, then upon shaking a uniform suspension will result. If red blood cells of one individual are mixed with the serum of another, then in some cases they will also be distributed uniformly, while in others the red blood cells will agglutinate, i.e., gather in clumps. This phenomenon is also called isoagglutination, since here the red blood cells agglutinate under the influence of serum of the same species. The first observations on isoagglutination were made in 1899-1900 (Schattock, Landsteiner, Grunbaum), and Landsteiner showed that the ability for isoagglutination is a property of normal sera. In different individuals, isoagglutination properties are different, and all humanity is divided in this respect into four groups, which were established independently by Jansky in 1907 and Moss in 1910. Characteristics of blood groups according to Jansky: 1. Red blood cells of individuals of group I are not agglutinated by any sera. Serum of individuals of group I agglutinates red blood cells of all other groups. 2. Red blood cells of individuals of group II are agglutinated by sera of individuals of groups I and III. Serum of individuals of group II agglutinates red blood cells of groups III and IV. 3. Red blood cells of group III are agglutinated by sera of individuals of groups I and II. Serum of individuals of group III agglutinates red blood cells of groups II and IV. 4. Red blood cells of group IV are agglutinated by sera of all other groups. Serum of individuals of group IV does not agglutinate any red blood cells. Moss's group I corresponds to Jansky's group IV, Moss's group IV corresponds to Jansky's group I. All these relationships are presented in Table 1. The Congress of American Immunologists and Bacteriologists in 1921 recognized it as necessary to use only Jansky's classification due to its priority and greater logic, since the groups are distributed in it in decreasing order. Groups I and II are most common (only Jansky's classification is given hereinafter). On average, 80% of all people belong to them (approximately 40% for each), about 15% fall on group III and about 5% on group IV. To explain the hemagglutination properties of the four blood groups, it has been assumed (Landsteiner, Dungern and Hirszfeld) that in red blood cells there are two different properties, two different agglutinable substances, or two agglutinogens—A and B. They can occur together or separately, and can also be simultaneously absent; absence is denoted by 0. Thus, there are four possibilities: 1) the property of red blood cells 0 corresponds to group I, 2) A—II, 3) B—III, 4) AB—IV group. Accordingly, in the sera there are hemagglutinins directed against A, denoted as anti-A or a, and directed against B, denoted as anti-B or β. In the blood, together with a certain agglutinogen of red blood cells, only those hemagglutinins that can physiologically exist simultaneously with these agglutinogens are present (Landsteiner's rule). Thus, in group I, which has neither A nor B, both agglutinins a and β are present; in group II with agglutinogen A, agglutinin β is present; in III together with B—agglutinin a; and finally in IV, which has both A and B, there are no agglutinins at all, which is denoted by a small 0. All these relationships are given in Table 2, where the properties of blood of each group are denoted by a formula. Table 2. Relationship of blood groups and agglutinins. Groups Red blood cells contain agglutinable substance Red blood cells are agglutinated by serum of following groups Serum contains agglutinins Formula I 0 I, II, III a and β 0 II A I, III β A III B I, II a β IV AB I, II, III 0 AB In contrast to bacterial agglutinins, which accumulate in the blood as a result of immunization, isoagglutinins are a property of normal sera and relate to constitutional features of the organism. Determination of blood groups is carried out by various methods: 1. Unknown red blood cells are determined using known (test) sera of groups II and III. Table 3. Determination of groups using known sera of groups II and III. Agglutination of unknown blood corpuscles. Serum of group II (A) Serum of group III (B) Group Formula + + I 0 + + II A + + III B + + IV AB 2. Unknown sera are determined using known red blood cells of groups II and III. Table 4. Determination of groups by two types of known red blood cells of groups II and III. Agglutination using unknown sera. Known red blood cells II (A) Known red blood cells III (B) Group Formula + + I 0 + + II A + + III B + + IV AB 3. Determination can be carried out using only one known blood of group II or III, using both red blood cells and serum of the test blood and known blood. Table 5. Determination of blood groups using red blood cells and serum of group II (A). Known serum II (A), unknown blood corpuscles Known red blood cells II (A), unknown serum Group Formula + + I 0 + + II A + + III B + + IV AB Table 6. Determination of blood groups using red blood cells and serum of group III (B). Known serum III (B), unknown red blood cells Known red blood cells III (B), unknown serum Group Formula + + I 0 + + II A + + III B + + IV AB As can be seen from the tables presented, in all these cases there are 4 combinations, which correspond to the four groups. The determination of the group each time is made according to the group formulas (see Table 2). Technique of H. Technically, the determination of groups is carried out by mixing known sera or red blood cells of groups II and III with red blood cells or serum of the test individual. The reaction is usually performed macroscopically in agglutination tubes or on slides. Many methods of performing the reaction have been proposed. One of the simplest methods of research consists of the following. An emulsion of the test red blood cells is prepared: for 1 cubic cm of 0.5% solution of Natrii citrici, prepared on physiological solution, 2 drops of the test blood are taken. 2 drops of this emulsion are mixed with 1 drop of test serum of group II (at one end of the slide) and group III (at the other end of the same slide). The reaction occurs very quickly and can be checked under a microscope. A control with red blood cells of group I is recommended. Lejtmann indicates a method of H., which apparently allows not only to determine the group, but also the titer of the agglutinogens and agglutinins being studied. The hemagglutination titer of different sera is different. Weak sera are unsuitable, as they often serve as a source of errors in determining groups. A serum is suitable for determination if when diluted four times the reaction occurs immediately and if its agglutinating ability does not disappear when diluted 16 times (Rubashkin). Agglutinogens of red blood cells are fully expressed already in newborns and even in the fetus. Hemagglutinins, however, begin to develop in the serum only in the first months of life. "Serological maturation" (Hirszfeld) ends by two years. At present, it is considered established that the group characteristic is constant for each person and does not change throughout life. Existing indications of changes in groups in various diseases require careful verification. From an anthropological point of view, differences in the frequency and distribution of groups in different races have been established. These differences mainly concern groups II and III. The characteristic for European peoples predominance of group II over group III—property A over property B—decreases in the direction of Asia and Africa, where the percentage of their distribution equalizes. L. and G. Hirszfeld the relationship between A and B called the biochemical index of the race (J). Its general formula (including here also group IV) is: J = (II + IV)/(III + IV) (in letters the percentage of corresponding groups is expressed). Example: among Germans, group I (0)—40%, group II (A)—43%, group III (B)—12% and group IV (AB)—5%. The true indicator for structure A will be group II + group IV (A is also included in the formula of group IV), i.e., 43 + 5 = 48, and for structure B—group III + group IV, i.e., 12 + 5 = 17; 48:17 = 2.8. Consequently, for Germans the biochemical index = 2.8. For Europeans J ranges from 2.0 to 4.0, for intermediate peoples—from 1.0 to 2.0, for Asian and African it is less than 1.0. In practice, isoagglutination is applied: 1. In blood transfusion, which at present cannot

This should be done without the most preliminary and thorough determination of the hemagglutinating properties of the donor's and recipient's blood. 2. In forensic medicine, a) In determining paternity. The group characteristics are inherited according to Mendel's rules, with traits A and ii being dominant. Dungern and Hirszfeld showed that a specific agglutinogen A or B never appears in children if it was not present in one of the parents, on the other hand, it may be absent in the child even if present in the parents. This forms the basis of the inheritance patterns and forensic-medical application of blood groups, mainly for establishing paternity or clarifying the origin of a child. Here it is important that based on group characteristics, in some cases paternity can be excluded. Example: a mother belonging to group I (0) and having a child of group II (A) names a subject of group I as the father. It is clear that this subject, as well as a subject of group III (B), cannot be the father of the child; the father must be a person with A in the group characteristic, i.e. belonging to group II or IV. But there are many people of groups II and IV; therefore, with this combination, a positive conclusion cannot be reached, and the examination can only answer presumptively, for example, N based on his blood group characteristic could be the father of this child. b) When examining blood (and dried) stains. Establishing a specific group here makes it possible to exclude that the blood in the stains belongs to persons with other groups; however, in relation to subjects with the same blood group, the answer, as in determining paternity, can only be presumptive.