Published on November 16, 2018
Blood Grouping: Blood Grouping DR QAZI IMTIAZ RASOOL : OBJECTIVES After completing this experiment, you should be able to: 1. Defne the terms blood “ groups” and “blood types”, and name the various blood group systems . 2. Describe the physiological basis of blood grouping and its clinical signifcance . 3. Describe the Landsteiner’s law and explain its basis 4. Describe the Rh factor and how it was discovered? What is its signifcance ? . OBJECTIVES Introduction : Introduction Over 200 blood antigens exist! Unfortunately, we only get to review the most relevant antigens Of all the blood group systems the ABO system is by far the most important It is the only one of the system where if you lack an antigen, you always have the corresponding antibody Anti-A and anti-B are potent hemolysins capable of causing intravascular hemolysis by bind complement to C9 SIGNIFICANCE OF BLOOD GROUP DETERMINATION : SIGNIFICANCE OF BLOOD GROUP DETERMINATION To avoid mismatched blood transfusion. To prevent Hemolytic disease of Newborn. Paternity test ( identify father --disputed paternity) For Research in anthropological & racial studies. To establish the identity of person(Medico – Legal importance) To study correlation between blood group & disease 4 Major Blood Group Systems at least 30-40 : Major Blood Group Systems at least 30-40 MAJOR BLOOD GROUP SYSTEM – Based on presence of Aglutinogens which are widely prevalent in the population 1.ABO blood group system 2.Rh blood group system 2. MINOR BLOOD GROUP SYSTEM - Based on presence of Aglutinogens which are found only in small portion of the population 1.MNS blood group system 2. P Blood group system 3. FAMILIAL BLOOD GROUP SYSTEM - Based on presence of Aglutinogens which are found only in few families 1.Lewis blood group system 2. Duffy blood group system 3.KELL blood group system 4. Bombay blood group system 5 Karl Landsteiner in Vienna in 1901: Karl Landsteiner in Vienna in 1901 Rule : . 1.If the particular antigen is present on RBCs membrane, the corresponding antibodies must be absent in plasma. 2 . If the particular antigen is absent on RBCs membrane , the corresponding antibodies must be present in plasma Nobel Prize in Physiology or Medicine in 1930. Also Landsteiner and Winner discovered Rh- 1940 Slide 7: Blood transfusion is a life-saving procedure in life-threatening i.e anemias ,blood loss antigen = or agglutinogens antibodies = agglutinins Procedure Blood Grouping: Forward and reverse typing Cross matching Recipient’s serum is combined donor’s RBC (a “major” cross-match ), 2. Recipient’s RBC combined with donor’s serum (a “minor ” cross-match), Inappropriate Physiological Applications ABH Ag—Tissue distribution : ABH Ag—Tissue distribution Gene expression is not restricted to RBC they code for the particular enzymes that catalyze formation of the carbohydrates but occurs universally in most epithelial and endothelial cells red cells white cells (in a weakened form) platelets (in a weakened form) body tissue lungs,pancreas,salivary glands body fluids (if a secretor) secretor refers to secretion of Ags in saliva, sweat, tears, semen, and serum 80% of people are secretors have Se genes ( SeSe or Sese )， 20% are nS . Monoclonal antibodies: Monoclonal antibodies igM m – Mu 900,000 Half-life: 5 to 10 days % of Ig in serum : 10% Serum level (mgml -1 ): 0.25 - 3.1 Complement activation : ++++ by classical pathway Interactions with cells: Phagocytes via C3b rceptors Transplacental transfer: No IgG 150,000 21 days 75% 10-16mg /ml same yes Slide 12: ABO genotype and phenotypes I A and I B are codominant Both I A and I B are dominant to I O A phenotype consists of only those traits or antigens that can be directly typed, whereas a genotype is the sum of all genes a person has inherited within a blood group system . (1 maternal and 1 paternal in origin) Phenotype Possible Genotype A 21 % AA or AO B 39 % BB or BO AB 9 % AB O 31 % OO Slide 14: "A “ and "B" antigens are also produced by some other plants and microorganisms. Thus, individuals who do not recognize 1 or more of these antigens as "self" will produce antibodies against the plant or microbial antigen s. NOTE; - are absent in a newborn ; start appearing in the plasma by the age of 3–4 months due to cross reactivity of ABO antigens present in naturally occurring bacteria, viruses , pollen, a blood transfusion or a tissue graft. Why do individuals produce antibodies to antigens they do not have? Slide 15: G ene is autosomal (the gene is not on either sex chromosomes) on the chromosome 9. A and B blood groups are dominant over the O blood group Frequency: A 1 = 80% and A 2 = 20 % . ABO antibodies are immune and will result in destroying incompatible cells which may result in the death of the recipient. NO IMMUNITY AGAINST THEM ABO inheritance and genetics Slide 16: A1 and A2. Difference between these two, is said to be quantitative: each A1 red cell has about 1 million copies of A antigen, A2 red cell has about 250,000 antigen molecules. Subgroups of A and B blood groups Slide 17: Common (C, D , and E c. d e ) 45 different types of Rh agglutinogens Note The antibodies against Rh factor do not occur naturally Rh Factor Example of Determining Genotype: Example of Determining Genotype Mom’s phenotype is group A, genotype AO Dad’s phenotype is group B, genotype BO B O A AB 25% AO 25% (Group A) O BO 25% (Group B) OO 25% (Group O) Mom Dad Offspring Blood Group AA BB 100% AB BO OO 50% each of B or O OO OO 100% O OO AO 50% each of A or O Slide 19: Why is an Rh incompatibility so dangerous when ABO incompatibility is not during pregnancy? Most anti-A or anti-B antibodies are of the IgM class (large molecules) and these do not cross the placenta. In fact, an Rh − / type O mother carrying an Rh + / type A, B, or AB foetus is resistant to sensitisation to the Rh antigen. Her anti-A and anti-B antibodies destroy any foetal cells that enter her blood before they can elicit anti-Rh antibodies in her. group AB are called "universal receivers." : Figure 19–6a group AB are called " universal receivers ." Antigens = agglutinogens Antibodies = agglutinins Blood transfusions – who can receive blood from whom ? People with blood group O are called "universal donors" and people with blood Methods for determination of ABO group of RBCs : Methods for determination of ABO group of RBCs Slide Method – Forward Typing: Slide Method – Forward Typing Principle: When red cells are mixed with various reagent antiseras (soluble antibody), agglutination will occur on the slides containing cells positive for (possessing the antigen) the corresponding antigen. No agglutination will occur when the red cells do not contain the corresponding antigen. Slide 23: Slide Blood Typing Rudimentary method CANNOT be used for transfusion purposes as “false positive” is when agglutination occurs not because the antigen is present, but cells may already be clumpled . “false negative” is 1 in which the cells are not clumped because there are too many cells or not enough reagent. Procedure: : Procedure: On the section of slide labeled anti-A place 1 drop of antibody A. On the section of slide labeled anti-B place 1 drop of antibody B. On the section of slide labeled anti-AB place 1 drop of antibody AB. On new slide labeled anti-D place 1 drop of antibody D. Place 1 drop of cells in each antibody containing circle. Carefully mix each solution with a separate applicator stick. Tilt slowly for 1 minute, then observe for the agglutination . Interpretation of the results:: Interpretation of the results: Strong agglutination constitutes a positive result. A smooth suspension of RBCs a fter 2 minutes is a negative result. Samples that give weak or doubtful reactions should be retested by Tube test ABO grouping Grading System for Reactions: Grading System for Reactions Grading of Agglutination Reaction: Grading of Agglutination Rea ction . A gglutination reaction may be graded A single large agglutinate (4+), A number of large (3 +), M edium or small masses with no free red cells (2+), M any small aggregates in the background of free red cells (1+) Tube Methods - Forward Typing : Tube Methods - Forward Typing - Prepare 2-5% cell suspension - Label Test tubes - Add 2 drops of Anti sera A, B , and D Slide 29: - Add 1 drop of 2-5% Patient Red Blood Cell suspension. - Mix the contents of the tubes gently and centrifuge for 15-30 seconds at approx. 900-1000 x g - Gently resuspend the RBCs buttons and examine for agglutination If the Rh test is negative, add a second drop of anti-D and incubate 15 minutes at 37 o C, then centrifuge and read again. Other methods for blood grouping: Other methods for blood grouping Gel Cards Gel Cards containing Anti-A, Anti-B, and Anti-A,B are used to test patient or donor red blood cells for the presence or absence of the A and/or B antigens. reverse (serum) grouping, the specific antibody (Anti-A, Anti-B, or Anti-D) is incorporated into the gel. This gel has been pre-filled into the microtubes of the plastic card. As the red blood cells pass through the gel, they come in contact with the antibody. Red blood cells with the specific antigen will agglutinate when combined with the corresponding antibody in the gel during the centrifugation step. Microplate Technique: Microplate Technique Microplate techniques can be used to test for antigens on red cells and for antibodies in serum. A microplate can be considered as a matrix of 96 “short” test tubes; the principles that apply to hemagglutination in tube tests also apply to tests in microplate . Add reagent and patient sample( red cells/ serum) Incubation, Centrifugation Red cell resuspension , Interpretation of results What is blood doping? When is it employed? : What is blood doping? When is it employed? Blood doping is the procedure in which some athletes used to get a unit or two of their own blood (or red cells ) removed and stored for a few weeks. It was then reinjected in 2–3 sessions a few days before an event . Summary: Summary Blood Group Antigens on cell Antibodies in plasma Transfuse with group A A Anti-B A or O B B Anti-A B or O AB A and B n1 AB, A, B or O O N1 Anti-A & B O Type O blood : Type O blood have the thinnest blood, strongest immune systems, strongest stomach acids, and live the longest of all the blood types. Type Os are however, prone to digestive disorders, more susceptible to arthritis, and thyroid disease due to an overactive immune system . you secrete different scents. Studies have shown that mosquitoes are most attracted to Type O blood and least attracted to Type A.