Lect 2

• Who discovered the ABO Blood Group System and in what year?

  Karl Landsteiner discovered the ABO Blood Group System in 1901.
• What was the significance of the dog-dog transfusion in 1665?


  It demonstrated the feasibility of blood transfusion.
• What did Denis's animal-human transfusion in 1667 result in?


  It led to the banning of experimentation with animal-human transfusions.
• What did Blundell contribute to the field of transfusion in 1818?


  He developed techniques and rational indications for human-human transfusion.
• What was the search for a blood substitute in the 1800s aimed at?


  It was aimed at addressing frequent severe reactions during transfusions.
• What is Landsteiner's Rule regarding antibodies and antigens?

  If an antigen is present on a patient's red blood cells, the corresponding antibody will NOT be present in the patient's plasma under normal conditions.
• What are the two principles regarding naturally occurring antibodies in the ABO blood group?

  1. Almost all normal healthy individuals above 3-6 months of age have naturally occurring antibodies to the ABO antigens they lack. 2. These antibodies are mostly of the IgM class.
• Why are naturally occurring antibodies termed as such?

  They were thought to arise without antigenic stimulation.
• What determines a blood group?

  The antigens on the red cell surface.
• What is the significance of red cell antigens during transfusion?

  They are crucial for compatibility during blood transfusions.
• What are the four blood types in the ABO system?


  Type A, Type B, Type AB, and Type O.
• How are the A and B antigens formed from the H antigen?

  By adding N-acetylgalactosamine to make A antigen and adding galactose to make B antigen.
• What is the relationship between genotype and blood type in the ABO system?

  • AA or AO → Type A
  • BB or BO → Type B
  • AB → Type AB
  • OO → Type O
• What is the percentage of the population for each blood type: A, B, AB, and O?

  1. 40%, B: 12%, AB: 6%, O: 42%.
• What happens to type A red cells when anti-A antibodies are present?

  They are lysed by the anti-A antibodies.
• What is the significance of forward blood grouping?

  It identifies the presence of antigens on red blood cells using anti-sera.
• What is the process of forward and reverse ABO blood grouping?

  • Forward grouping: Tests patient red cells with anti-sera to identify antigens.
  • Reverse grouping: Tests patient serum with reagent red blood cells to identify antibodies.
• What does a positive reaction in reverse grouping indicate?

  It indicates the presence of antibodies to the corresponding antigens in the serum.
• What blood types can a type O recipient receive?

  Type O only.
• What is the universal donor blood type?

  Type O is the universal donor.
• What blood types can a type AB recipient receive?

  Type AB, A, B, or O.
• What is the interpretation of a patient testing positive for both anti-A and anti-B antibodies?

  It indicates that the patient is blood type O.
• What does the presence of anti-A antibodies in a type A blood sample indicate?

  It indicates that the sample is not type A blood.
• What is the role of anti-B antibodies in blood typing?

  They lyse type B red cells.