Blood Groups and Blood Transfusion (PDF)

Blood group and Blood Transfusion Dr.Rasha Eldeeb Associate Professor of Physiology www.gmu.ac.ae COLLEGE OF HEALTH SCIENCES  Blood Group and Blood Transfusion Learning Objectives: Describe Multiplicity of Antigens in...

Blood group and Blood Transfusion Dr.Rasha Eldeeb Associate Professor of Physiology www.gmu.ac.ae COLLEGE OF HEALTH SCIENCES  Blood Group and Blood Transfusion Learning Objectives: Describe Multiplicity of Antigens in the Blood Cells Describe the O-A-B Blood Types Describe the Rh Blood Types Enumerate the Importance of knowing the Blood groups Describe the indication of blood transfusion. Describe the effect of incompatible blood transfusion. Describe Hemolytic Disease of the Newborn (Erythroblastosis fetalis) To Start with … What is Blood Group?  Blood Group There are at least 30 commonly occurring antigens and hundreds of other rare antigens. Most of the antigens are weak but the two particular types of antigens that are much more likely than the others to cause blood transfusion reactions are the O-A-B system of antigens and the Rh system  O –A-B Blood Groups Two antigens—type A and type B—occur on the surfaces of the red blood cells in a large proportion of human beings. These antigens (also called agglutinogens because they often cause blood cell agglutination) that cause most blood transfusion reactions. Blood is normally classified into four major O-A-B blood types, depending on the presence or absence of the two agglutinogens, the A and B agglutinogens oWhen neither A nor B agglutinogen is present, the blood is group O (Universal Donner). oWhen only type A agglutinogen is present, the blood is group A. o When only type B agglutinogen is present, the blood is group B. oWhen both A and B agglutinogens are present, the blood is group AB (Universal Recipient)  Agglutinins (antibody) When type A agglutinogen (Antigen) is not present in a person’s red blood cells, antibodies known as anti-A agglutinins develop in the plasma. Also, when type B agglutinogen is not present in the red blood cells, antibodies known as anti-B agglutinins develop in the plasma Note that type O blood, although containing no agglutinogens, does contain both anti-A and anti-B agglutinins Type A blood contains type A agglutinogens and anti-B agglutinins; type B blood contains type B agglutinogens and anti-A agglutinins Finally, type AB blood contains both A and B agglutinogens but no agglutinins  Titer of the Agglutinins at Different Ages Immediately after birth, the quantity of agglutinins in the plasma is almost zero. 2 to 8 months after birth, an infant begins to produce agglutinins—anti-A agglutinins when type A agglutinogens are not present in the cells, and anti-B agglutinins when type B agglutinogens are not in the cell A maximum titer is usually reached at 8 to 10 years of age, and this gradually declines throughout the remaining years of life The O-A-B Blood Types With Their Genotypes and Their Constituent Agglutinogen and Agglutinin (Antibody) Relative Frequencies of Different O-A-B Blood Types 9  Rh Blood Group There are 6 common types of Rh antigens, each of which is called an Rh factor. These types are designated C,D, E, c, d, and e. Anyone who has this type of antigen is said to be Rh positive, whereas a person who does not have type D antigen is said to be Rh negative. Rh agglutinins (Rh antibodies) are not naturally present in plasma, but these antibodies are formed only in plasma of Rh –ve persons being sensitized by transfusion of the Rh +ve blood or by the presence of Rh +ve fetus in Rh –ve mother (after labour or abortion) About 85 % of all people are Rh positive and 15 % Rh negative.  Differences between anti Rh agglutinins & ABO agglutinins ABO agglutinins Anti Rh agglutinins Naturally occurring in the plasma Not naturally occurring but they are & are formed spontaneously formed in plasma of Rh –ve persons after transfusion with Rh +ve blood Transfusion reactions with ABO agglutinins are immediate Transfusion reactions with Rh agglutinins occur only after previously exposure to ABO agglutinins are large in size Rh blood (IgM), so they can not cross the placenta Rh agglutinins are small in size (IgG), so they can cross the placenta Now… What Is The Importance Of Blood Groups?  The Importance of Blood Groups When & Why we do blood grouping? In blood transfusion (to avoid incompatibility reactions) http://t3.gstatic.com/images?q=tbn:pRVPq_xdAbMWUM:http://www.theodora.com/drugs/images/176.jpg In marriage (to avoid erythroblastosis fetalis) Medicolegal importance; in cases of disputed paternity, blood grouping tests http://t3.gstatic.com/images?q=tbn:r2uj8Zw7-n9r3M:http://divorcelawyers.co.za/wp-content/uploads/2010/08/paternity-test.jpg http://t3.gstatic.com/images?q=tbn:v7g7G9AtShMfnM:http://www.labworksfla.com/dna%2520strand.jpg can only exclude paternity but can not prove it Now… What Are the Indications of Blood Transfusion?  Indications of Blood Transfusion Severe hemorrhage (to restore blood volume). Severe anemia (to provide patient with the deficient Hb & RBCs). Erythroblastosis fetalis (Exchange blood transfusion). Hemophilia (to supply the missing clotting factor). Purpura (to increase platelet count). Leuopenia (to increased WBC’s). Hypoproteinemia (to increase plasma proteins).  Precautions before blood transfusion Blood should be taken from healthy donors with the following characters: o Age: 20 – 60 years. o Weight: not less than 55 Kg. o Blood pressure: should be within normal. o Hb: should not be less than 13 g %. Transfused blood must be stored at 4 oC & for a period not exceeding 21 days. Blood grouping & double cross matching tests should be done to avoid incompatible blood transfusion reactions. What is the Effect of Incompatible Blood Transfusion?  Effects of incompatible blood transfusion Agglutination of donor’s RBCs leads to obstruction of small blood vessels and capillaries causing tingling, pain sensation, chest pain, dyspenea, tachycardia, hypotension and even death. Hemolytic jaundice: due to excessive bilirubin formation from Hb released from hemolysed RBCs. Severe hypotension: due to release of K+ and histamine from hemolysed RBCs causing generalized vasodilation (V.D.). Oliguria (or anuria): due to: o Hypotension o Precipitation of Hb in renal tubules in the form of acid hematin → blocking or renal tubules → acute renal failure.  Prevention of Incompatible Blood transfusion Blood Typing Before giving a transfusion to a person, it is necessary to determine the blood type of the recipient’s blood and the blood type of the donor blood so that the bloods can be appropriately matched. This is called blood typing and blood matching They are performed in the following way: The red blood cells are first separated from the plasma and diluted with saline One portion is then mixed with anti-A agglutinin and another portion with anti-B agglutinin. After several minutes, the mixtures are observed under a microscope If the red blood cells have become clumped— that is, “agglutinated”—one knows that an antibody antigen reaction has resulted Now… What Is Erythroblastosis Fetalis?  Erythroblastosis Fetalis (Hemolytic Disease of the Newborn) Erythroblastosis fetalis is a disease of the fetus and newborn child characterized by agglutination and phagocytosis of the fetus’s red blood cells In most instances of erythroblastosis fetalis, the mother is Rh negative and the father Rh positive. The baby has inherited the Rh-positive antigen from the father, There is usually no problem with the first baby The mother develops anti-Rh agglutinins from exposure to the fetus’s Rh antigen during the delivery process So, during the second pregnancy, the mother’s agglutinins diffuse through the placenta into the fetus and cause red blood cell agglutination Erythroblastosis fetalis occurs in the first baby of a mother previously sensitized by Rh antigen from previous( Rh +ve) blood transfusion or previous pregnancy or abortion. Now… How to Treat and Prevent Erythroblastosis Fetalis?  Treatment of the Erythroblastosis Neonate One treatment for erythroblastosis fetalis is to replace the neonate’s blood with O Rh-negative blood About 400 milliliters of Rh-negative blood is infused over a period of 1.5 or more hours while the neonate’s own Rh- positive blood is being removed This procedure may be repeated several times during the first few weeks of life, mainly to keep the bilirubin level low and thereby prevent kernicterus By the time these transfused Rh-negative cells are replaced with the infant’s own Rh-positive cells, a process that requires 6 or more weeks, the anti- Rh agglutinins that had come from the mother will have been destroyed  Prevention of Erythroblastosis Fetalis In the 1970’s, a dramatic reduction in the incidence of erythroblastosis fetalis was achieved with the development of Rh immunoglobulin globin, an anti-D antibody that is administered to the expectant mother starting at 28 to 30 weeks of gestation http://t0.gstatic.com/images?q=tbn:LvQQGXbrP4d2gM:http://2.bp.blogspot.com/_TqZsR17bc7k/SfZDaCvdt7I/AAAAAAAABcE/5o0vY_N2yww/s400/doctorneedle.png The anti-D antibody is also administered to Rh-negative women who deliver Rh- positive babies to prevent sensitization of the mothers to the D antigen at the time of delivery or up to 72 hours after delivery Learning Resources: 1. Marieb EN. Human Anatomy and Physiology, 9th Edition, Pearson International Edition; 2014. ISBN-13: 978-1-2920-2649-7 2. Guyton, Arthur C. Textbook of medical physiology / Arthur C. Guyton, John E. Hall.—11th ed. 3. Ganong's Review of Medical Physiology/Kim E. Barrett, Susan M. Barman, Scott Boitano and Heddwen L.Brooks,23rd ed. 4. Instructional Web site 5. Lectures PDF on Moodle 6. https://www.clinicalkey.com/#!/content/book/3-s2.0-B9780702031144000026  DISCLAMER The contents of this presentation, can be used only for the purpose of a Lecture, Scientific meeting or Research presentation at Gulf Medical University, Ajman. www.gmu.ac.ae