Hemagglutination

Hemagglutination ( Gr. Heme (αἷμα) blood , lat. Agglutinare to attach ) means a visible clumping ( agglutination ) of erythrocytes . A distinction is made between hemagglutination based on a lectin or as an antigen-antibody reaction .

Hemagglutinins

Phytohemagglutinins

Phytohemagglutinin L (PHA-L)

Hemagglutination due to a PHA (phytohemagglutinin or phytoagglutinin). These are lectins of vegetable origin, which agglutinate erythrocytes. Important PHAs are the phasins or phaseolamines, which z. B. occur in bean or chickpea . Phasins are classified as "very toxic ", but are mostly detoxified by cooking.

Fungal hemagglutinins

Not only plants, but also fungi can contain hemagglutinins. So z. B. the Kahle Krempling , formerly a popular edible mushroom whose haemagglutinins can lead to severe digestive problems. Therefore, the Kahle Krempling is now counted among the poison mushrooms and may no longer be offered on markets.

Antigen-antibody reaction

When an antibody binds to two erythrocytes, cross-linking ( precipitation ) occurs between the red blood cells. This precipitate is visible.

Direct hemagglutination

Specific antibodies bind to certain molecules on the cell surface of the erythrocytes . The direct hemagglutination plays e.g. B. in the blood group intolerance a role. A person with blood group A has the corresponding molecule on their erythrocytes. Your body does not make antibodies against this antigen. However, a second person with blood group B has antibodies against this blood group characteristic A in their blood. If blood or serum from the person with blood group B is transferred to the person with blood group A, the antibodies bind to the corresponding antigens on the erythrocytes and it occurs to the formation of immune complexes in the blood vessels and thus to the transfusion incident . To avoid this, a bedside test is carried out before a blood transfusion (in addition to other examinations) , in which the blood of the recipient is examined with appropriate antibodies and the blood group is determined again directly before the transfusion based on the agglutination.

Hemagglutination inhibition test of different influenza samples, diluted from left to right

Clearly visible clumping in anti-A and anti-Rhesus-D, using the example of a blood transfusion obligate bedside tests

Indirect hemagglutination

First, antigens are bound to the surface of the erythrocytes. Antigen-homologous antibodies then bind to these. Indirect hemagglutination is used in serological examinations. On the one hand, certain pathogens can be indirectly detected if the erythrocytes are loaded with specific antigens (e.g. Vi antigen in typhoid fever , latex hemagglutination test in syphilis ).

Application in laboratory diagnostics

In the hemagglutination inhibition test , the inhibition of hemagglutination between antigen-laden erythrocytes and antiserum is measured using a sample. If this contains many of the antigens to be examined, the haemagglutination is weaker, as the antibodies bind more strongly to the free antigens in the sample and thus contribute less to the cross-linking of the erythrocytes. The test is also used to quantify antibodies against hemagglutinating viruses (especially influenza viruses). If erythrocytes are added to influenza viruses, complete hemagglutination occurs. However, if the serum to be examined contains antibodies against the influenza viruses, hemagglutination is prevented. Via dilution series, so-called titration , the amount of serum to be examined can be determined, which can just barely prevent hemagglutination by a given amount of virus. This is called the hemagglutination inhibitor .

literature

Pschyrembel Clinical Dictionary 258th edition De Gruyter Berlin 1998
Fritz H. Kaser et al. Medical microbiology 10th edition Georg Thieme Stuttgart 2001
Herbert Hof, Rüdiger Dörries Dual Series Medical Microbiology 3rd Edition Georg Thieme Verlag Stuttgart 2005
Volker Kiefel, Christian Müller-Eckhardt (ed.): Transfusion medicine and immunohematology: Basics - Therapy - Methodology. Springer, Berlin / Heidelberg / New York 2010, ISBN 3-6421-2764-9 , p. 79 f
Reinhold Eckstein, Robert Zimmermann: Immunohematology and clinical transfusion medicine: theory and practice compact paperback. Edition 7, Urban & Fischer Verlag / Elsevier, Munich 2015, ISBN 3-4373-1681-8 , p. 13

Individual evidence

↑ Michel Boivin, Bernard Flourie, Robert A. Rizza, Vay Liang W. Go, Eugene P. DiMagno: Gastrointestinal and metabolic effects of amylase inhibition in diabetics. In: Gastroenterology 94, No. 2, 1988, pp. 387-394 ( PDF ).
↑ Information center against poisoning, Botanical Garden of the Rheinische Friedrich-Wilhelms-Universität Bonn: common bean (Phaseolus vulgaris) .
↑ Rostyslav Antonyuk, Alexander Lutsyk, Volodymyr Antonyuk: Lectin purification from fruiting bodies of brown roll-rim fungus, Paxillus involutus (Fr.) Fr., and its application in histochemistry. In: Rom J Morphol Embryol 55, No. 3, 2014, pp. 787-796 ( PDF ).

[1] Michel Boivin, Bernard Flourie, Robert A. Rizza, Vay Liang W. Go, Eugene P. DiMagno: Gastrointestinal and metabolic effects of amylase inhibition in diabetics. In: Gastroenterology 94, No. 2, 1988, pp. 387-394 ( PDF ).

[2] Information center against poisoning, Botanical Garden of the Rheinische Friedrich-Wilhelms-Universität Bonn: common bean (Phaseolus vulgaris) .

[3] Rostyslav Antonyuk, Alexander Lutsyk, Volodymyr Antonyuk: Lectin purification from fruiting bodies of brown roll-rim fungus, Paxillus involutus (Fr.) Fr., and its application in histochemistry. In: Rom J Morphol Embryol 55, No. 3, 2014, pp. 787-796 ( PDF ).