Blood Groups & Blood Transfusion HMIM BLOCK 224 Dr. Shaikh Mujeeb Ahmed Assistant Professor AlMaarefa College

Objectives Different types of Blood groups blood group system Explain blood typing and how it is used to avoid adverse reactions following blood transfusions. Describe how blood reactions may occur between fetal and maternal tissues.

Blood Groups and Transfusions In the year 1900, identification of the ABO blood antigen gene explained the observed blood type incompatibilities by Karl Landsteiner Today there are 31 different genes known to contribute to the surface features of RBCs determining compatibility between blood types

Blood Group Systems Major systems Minor ABO Rhesus system(Rh) MN P Familial blood groups

Importance of Blood Groups Transfusion of blood Association with disease Duodenal ulcers are more common in group O than in A or B Tumors of salivary glands, stomach and pancreas are more common in group A than in group O individuals.

Antigens and Antibodies Terms to become familiar with: Agglutination – clumping of red blood cells in response to a reaction between an antibody and an antigen Antigens – a chemical that stimulates cells to produce antibodies Antibodies – a protein that reacts against a specific antigen

Type A blood Type B blood Type AB blood Type O blood Red blood cell Anti-B antibody Red blood cell Anti-A antibody Antigen A Antigen B Type A blood Type B blood Red blood cell Anti-A antibody Anti-B antibody Antigen A Antigen B Red blood cell Type AB blood Type O blood

Agglutinated red blood cells Red blood cell Antigen A Anti-B antibody Anti-A antibody (a) (b) (c) (d)

ABO Blood Group Based on the presence or absence of two major antigens on red blood cell membranes Antigen A Antigen B

Antigens and antibodies of the ABO blood group Blood Type Antigen Antibody A Anti B B Anti A AB A and B Neither Anti A nor Anti B O Neither A nor B Both Anti A and Anti B

Genotype of ABO blood groups Possible Genotype(s) A AA, AO B BB, BO AB O OO

Landsteiner’s law. If an agglutinogen (antigen) is present on the RBCs the corresponding agglutinin (anti body) must be absent in the plasma If an agglutinogen (antigen) is absent on the RBCs the corresponding agglutinin (anti body) must be present in the plasma The first law is applicable to all blood groups. But the second part is not necessary always, its true for ABO blood groups.

Rh Blood Group The Rh blood group was named for the rhesus monkey The group includes several Rh antigens or factors (Cc, Dd & Ee) Rh positive – presence of antigen D or other Rh antigens on the red blood cell membranes Rh negative – lack of these antigens The seriousness of the Rh blood group is evident in a fetus that develops the condition erythroblastosis fetalis or hemolytic disease of the newborn

Erythroblstosis Fetalis + – Rh-negative woman with Rh-positive fetus Cells from fetus enter woman’s bloodstream In the next pregnancy, maternal antibodies attack fetal red blood cells Woman becomes sensitized— antibodies ( + ) form to fight

Erythroblastosis Fetalis (Hemolytic disease of the newborn-HDN) Clinical Features Edema (Hydrops) Jaundice Anemia Enlarged Liver & Spleen

Erythroblastosis Fetalis (Hemolytic disease of the newborn-HDN) Treatment Exchange blood transfusion Prevention Rh immune globulin (RhIG) injections to the Rh –negative mother during pregnancy

Blood groups in local population Percentage of Population O + 48 % A + 24 % B + 17 % AB + 4 % Rh Positive are about 93% (90-95%) O- A- 2% B- 1 % AB- 0.23% Rh negative are about 7% (5-10%)

Blood transfusion Autologus blood transfusion Blood grouping and cross matching Donor’s RBCs + Recipient’s plasma (major cross matching) Recipients RBCs + Donor’s plasma (minor cross matching)

Proffered And Permissible Blood Types For Transfusion Blood Type of Recipient Preferred Blood Type of The Donor Permissible Blood Type of The Donor (In Extreme Emergency) A O B AB A B A,B, O No alternate type

Complications of Blood Transfusion Fatal hemolytic reactions in mismatched reactions. Rapid hemolysis Jaundice Renal tubular damage Circulatory overload – if rapid transfusion Hemosiderosis – repeated blood transfusion Electrolyte disturbances Transmission of disease Hepatitis – B or C AIDS