1. BLOOD GROUPS AGGLUTINOGENS (Antigens) Complex oligosaccharide substances on the surface of the RBC membrane AGGLUTININS Antibodies against agglutinogens Present in plasma of individuals after birth

2. Two major blood group systems : ABO system - 4 blood groups Rh system- Rh + and Rh - A B AB O

3. ABO system Blood groupAgglutinogensAgglutinins (on RBC) (in plasma) AA Anti-B BB Anti-A AB A, B None O NoneAnti-A, Anti-B

4. Inheritance of blood group antigens : A & B - Mendelian dominant O - recessive Phenotype Genotype AAA - homozygous AO - heterozygous B BB or BO AB AB O OO

5. F G C G G FF G G GG G GG G CC H antigen A antigen B antigen C Ceramide G GG G Glucose F Fucose G Galactose G N-acetylgalactosamine Ganong – Fig.27-21

6. Rh system Present only on RBCs 3 main types of antigens - C, D (most antigenic), E If a person has antigen D D +ve or Rh +ve antigen D is absent D -ve or Rh -ve Unlike ABO antibodies, Anti-D antibodies do not develop without exposure of a D -ve individual to D +ve RBC - by transfusion or during pregnancy

7. Blood grouping This is performed by mixing an individual’s red blood cells with different types of antisera on a glass slide and seeing whether agglutination occurs.

8. Antisera are commercially available

9. Clumping or Agglutination of RBCs Blood group - A +

10. What is the blood group ?

14. Donor’s RBCsRecipient’s plasma Blood samples to beSerum containing typed is added to the Anti-A Anti-B drops of serum antibodies antibodies Group A Group B Group AB Group O Agglutination or clumping of RBCs Cross Matching

15. Possible complications of blood transfusions 1. Incompatibility reactions Antigens on donor’s RBCs+ Antibodies in recipient’s plasma RBC Agglutination Clumps I/V haemolysisrelease of Hb may block Haemoglobinaemia blood vessels and JaundiceRenal failure ‘DEATH’

16. 2. Fever - due to the presence of antibodies against transfused WBCs and platelets 3. Allergic reactions - asthma 4. Circulatory overload 5. Iron overload 6. Air embolism - air can go into the circulation 7. Transmission of diseases - Malaria, hepatitis B, AIDS, Syphilis To avoid these complications “ Autologous transfusion” can be done.

17. Haemolytic disease of the newborn (HDN) * ABO Incompatibility – common but mild * Rh Incompatibility

18. Haemolytic disease of the newborn (HDN) - Rh incompatibility - When mother is Rh -ve and baby is Rh +ve fetal blood can leak into maternal circulation at the time of the delivery mother is sensitized formation of Anti-D antibodies in mother’s circulation

19. These antibodies can cross the placenta in subsequent pregnancies Haemolysis of fetal RBCs ‘Haemolytic disease of the new born’ (Erythroblastosis fetalis)

20. Complications- 1. If haemolysis is severe death of the fetus in the uterus 2. Severe anaemia 3. Severe jaundice 4. Oedema (hydrops fetalis) 5. Destruction of neuronal cells due to deposition of bilirubin nervous signs (Kernicterus) ‘Rh immune globulin (Rhogam) - anti-Rh antibodies’ injection prevents sensitization of mother’s immune system with Rh + antigen.