BLOOD GROUPS

1. BLOOD GROUPS

2. First Blood Transfusions Harvey Discovered Circulation of Blood 1628 Wilkins & Lower Transfusions from dog to dog 1665-’66 1667 Jean-Baptiste Denis Performed first recorded blood transfusions from animals to humans

3. 19th Century Transfusions 1818 James Blundell, Obstetrician First transfusion of human to human

4. Early transfusion: Paris, France

5. 20th Century Transfusions 1901 Karl Landsteiner Discovers A, B, O Blood Groups Nobel in 1930

6. 20th Century Transfusions 1902 AB Group discovered Importance of crossmatching blood between donor & recipient 1907 Sodium Citrate proposed as anticoagulant 1914 1936 First Blood Bank: Barcelona, Spanish Civil War Levine & Landsteiner, Rhesus blood Group System 1940

7. Human Blood Groups • RBC membranes have glycoprotein antigens on their external surfaces • These antigens are: • Unique to the individual • Recognized as foreign if transfused into another individual • Promoters of agglutination and are referred to as agglutinogens • Presence or absence of these antigens is used to classify blood groups

8. Blood Groups • Humans have 30 varieties of naturally occurring RBC antigens • The antigens of the ABO and Rh blood groups cause vigorous transfusion reactions when they are improperly transfused • Other blood groups (M, N, Dufy, Kell, and Lewis) are mainly used for legalities

9. Blood Grouping • Determined by antigens (agglutinogens) on surface of RBCs • Antibodies (agglutinins) can bind to RBC antigens, resulting in agglutination (clumping) or hemolysis (rupture) of RBCs • Groups • ABO and Rh

10. ABO Blood Groups • The ABO blood groups consists of: • Two antigens (A and B) on the surface of the RBCs • Two antibodies in the plasma (anti-A and anti-B) • An individual with ABO blood may have various types of antigens and spontaneously preformed antibodies • Agglutinogens and their corresponding antibodies cannot be mixed without serious hemolytic reactions

11. Genetic Determination of the Agglutinogens • Two genes, one on each of two paired chromosomes, determine the O-A-B blood type. • These genes can be any one of three types but only one type on each of the two chromosomes: type O, type A, or type B. • The type O gene is either functionless or almost functionless, so that it causes no significant type O agglutinogen on the cells. • Conversely, the type A and type B genes do cause strong agglutinogens on the cells.

12. Relative Frequencies of the Different Blood Types

13. ABO Blood Groups

15. Agglutinins • Group A - anti-B agglutinin, • Group B – agglutinin • Group O – both anti-B and anti-A agglutinins • AB Group – no agglutinin

16. Origin of Agglutinins in the Plasma • The agglutinins are gamma globulins, as are almost all antibodies • Most of them are IgM and IgG immunoglobulin molecules. • But why are these agglutinins produced in people who do not have the respective agglutinogens in their red blood cells? • Small amounts of type A and B antigens enter the body in food, in bacteria, and in other ways, and these substances initiate the development of the anti-A and anti-B agglutinins

17. Blood Typing

18. ABO Blood Groups

19. Figure.Average titers of anti-A and anti-B agglutinins in the plasma of people with different blood types.

20. Rh antigen Rh+RBC Rh- RBC Rhesus Grouping • The other major blood group system is determined by the presence of the Rhesus protein antigen on RBC. • Blood with the Rhesus antigen on RBC’s is termed rhesus positive (Rh+) while the absence of the rhesus antigen makes the blood rhesus negative (Rh-).

21. Rh Factor • Agglutinins do not occur naturally, they are produced after being exposed to the antigen • CcDdEe genes determine the antigen type • The most important and common antigen is D • Its antibodies are called anti-D

22. Rh Blood Groups • There are six different Rh agglutinogens, three of which (C, D, and E) are common • Presence of the Rh agglutinogens on RBCs is indicated as Rh+ • Anti-Rh antibodies are not spontaneously formed in Rh– individuals • However, if an Rh– individual receives Rh+ blood, anti-Rh antibodies form • A second exposure to Rh+ blood will result in a typical transfusion reaction

23. Rh Blood Group • First studied in rhesus monkeys • Types • Rh positive: Have these antigens present on surface of RBCs • Rh negative: Do not have these antigens present • Hemolytic disease of the newborn (HDN) • Mother produces anti-Rh antibodies that cross placenta and cause agglutination and hemolysis of fetal RBCs

24. Rh Mismatch & Reaction Father Rh (+) Mother Rh (-) Newborn Rh (+) • Hemolytic disease of the newborn(eritroblastosis fetalis) • Kernicterus

25. Hemolytic Disease of the Newborn • Hemolytic disease of the newborn – Rh+ antibodies of a sensitized Rh– mother cross the placenta and attack and destroy the RBCs of an Rh+ baby • Rh– mother becomes sensitized when Rh+ blood (from a previous pregnancy of an Rh+ baby or a Rh+ transfusion) causes her body to synthesis Rh+ antibodies • The drug RhoGAM can prevent the Rh– mother from becoming sensitized • The new born is anemic and hypoxic • Treatment of hemolytic disease of the newborn involves pre-birth transfusions and exchange transfusions after birth

27. It is a solution of IgG anti-D (anti-Rh) • It binds and destroys fetal Rh D positive erythrocytes that have passed through the placenta from the fetus to the maternal circulation. • This prevents maternal B-cell activation and memory cell formation. • With the widespread use Rho(D) Immune Globulin Rh disease of the fetus and newborn has almost disappeared.

28. Blood Transfusions Transfusion of wrong blood type can cause 2 problems e.g. transfuse type A blood into type B recipient: 1) Donor B antibodies attack recipients RBC’s which have B antigen (in practice diluted to such an extent - negligible) 2) Recipients A antibodies attack donor RBC’s which have A antigen Type AB - no antibodies therefore universal recipients Type O - no antigens therefore universal donors

29. Blood Transfusions • Whole blood transfusions are used: • When blood loss is substantial • In treating thrombocytopenia • Packed red cells (cells with plasma removed) are used to treat anemia

30. DID YOU KNOW? • When someone donates a pint of blood, that blood is separated into red cells, plasma and platelets.

31. Transfusion Reactions • Transfusion reactions occur when mismatched blood is infused • Donor’s cells are attacked by the recipient’s plasma agglutinins causing: • Diminished oxygen-carrying capacity • Clumped cells that impede blood flow • Ruptured RBCs that release free hemoglobin into the bloodstream • Circulating hemoglobin precipitates in the kidneys and causes renal failure

32. Agglutination Reaction

33. Plasma Volume Expanders • When shock is imminent from low blood volume, volume must be replaced • Plasma or plasma expanders can be administered

34. Plasma Volume Expanders • Plasma expanders • Have osmotic properties that directly increase fluid volume • Are used when plasma is not available • Examples: purified human serum albumin, plasminate, and dextran • Isotonic saline can also be used to replace lost blood volume

35. Transplantation of Tissues and Organs • Autografts • Isografts • Allografts • Xsenografts

36. Tissue Typing – The HLA Complex of Antigens • HLA antigen complex • There are about 150 different antigens to choose from • Six of these antigens are present on the tissue cell membranes of each person • The HLA antigens occur on the white blood cells as well as on the tissue cells.

37. Suppression of immune system • Importance of T lymphocytes • Glucocorticoid hormones • Drugs with toxic effects on the lymphoid tissue (such as Azathioprine) • Cyclosporine has a specific inhibitory effect on T-helper cells (T-cell mediated rejection)