Blood Group Systems By Oluwadare Ogunlade PDF

BLOOD PHYSIOLOGY: BLOOD GROUP SYSTEMS Oluwadare Ogunlade 1 15 January 2025  Learning Objectives The students should be able to; 1. Classify Blood Groups 2. State the clinical significance of blood groups  Introduction  All people have blood as a common a...

BLOOD PHYSIOLOGY: BLOOD GROUP SYSTEMS Oluwadare Ogunlade 1 15 January 2025  Learning Objectives The students should be able to; 1. Classify Blood Groups 2. State the clinical significance of blood groups  Introduction  All people have blood as a common attribute.  Blood of all people is made up of the same basic components; red blood cells, white blood cells, platelets, and plasma.  Blood of all people has the same function but with genetically linked variation in structure.  Blood is divided into types defined by the presence or absence of certain proteins on the cell membranes of red blood cells.  Common blood group types are ABO and Rhesus Systems. Red Cells Membrane Proteins  Blood Group Categories  Blood groups are classified based on the type of antigen on the cell membrane of red blood cells.  Two common types commonly determined in clinical practice are;  ABO blood group: A, B, AB and O  Rhesus factor; Rh + or Rh –  All together, 8 common types exist; 5 15 January 2025  ABO Blood Group System  The ABO blood group system was discovered by the Austrian Scientist Karl Landsteiner in in 1901.  The types of ABO blood group are defined based on the nature of genetically determined antigen(agglutinogen) on the surface of the red blood cell membrane.  The four common types of ABO blood group include: A,B,AB, and O 6 15 January 2025  Nature of ABO antigens  H substance is the precursor oligosaccharide on the cell membrane upon which A and B antigen are formed.  A antigen is created by the addition of N-acetylgalactosamine to H substance on the cell membrane.  B antigen is created by the addition of galactose to the H substance  The genes that determine the A and B phenotypes are found on chromosome 9p.  The gene products are glycosyl transferases, which confer the enzymatic capability of attaching the specific antigenic carbohydrate. 7 15 January 2025  H substance, A & B Antigen 8 15 January 2025  ABO Blood Group Importance  ABO blood group is clinically important because an individual produces natural antibodies to the ABH carbohydrate which is absent.  These naturally occurring antibodies are called isoagglutinins.  An individual’s serum automatically contains genetically determined non-complementary antibodies to their red cell antigens.  This implies that type A individual makes anti-B antibody while type B individual produces anti-A antibody 9 15 January 2025  ABO Blood Groups Blood Antigen Antibodies in Group serum A A Anti B(β) B B Anti A (α) AB AB None O No antigen Anti A and Anti B 10 15 January 2025  Blood Group A  A person with blood group A will have A antigen on the surface of the red blood cells but the serum will contain antibodies against B antigen.  A person with blood group A can donate blood to someone with blood group A or AB.  A person with blood group A can receive blood from someone with blood group A or O. 11 15 January 2025  Blood Group B  A person with blood group B will B antigens on the surface of the red blood cells but the serum will contain antibody against A antigen.  A person with blood group B can donate blood to a person with blood group B or AB.  A person with blood group B can receive blood from a person with blood group B or O. 12 15 January 2025  Blood Group O  A person with blood group O lacks either A or B antigens on the red cell membrane but the serum will contain antibodies against both A and B antigens.  A person with blood group O can only receive blood from a person with blood group O.  A person with blood group O can donate blood to a person with any of ABO blood group(A,B,AB or O). 13 15 January 2025  Blood Group AB  A person with blood group AB will have both A and B antigens on the surface of their red blood cells but the serum does not contain antibody against either A or B antigen.  A person with blood group AB can only donate blood to a person with blood group AB.  A person with blood group AB can receive blood from a person with any of ABO blood groups (A,B,AB or O). 14 15 January 2025  Bombay Blood Group  Bombay blood group is rare,first discovered in Bombay now known as Mumbai in India by Dr.Y.M. Bhende in 1952.  This blood group lacks H gene and therefore cannot make H substance(the backbone for A and B antigen).  The serum contains anti-A, anti-B, and anti-H  Individuals with this blood group lacks A and B antigens and type as O.  Agglutination occurs during cross matching because the anti- H agglutinates O cells  Bombay blood group can only receive blood from individuals with Bombay blood group. 15 15 January 2025  Rhesus Blood Group System  Rhesus antigen(factor) is located on the red blood cell membrane.  It was discovered in 1937 by Karl Landsteiner and Alexander S. Wiener  Type D antigen is more antigenic and more prevalent.  The D antigen is inherited as one gene on the short arm of the chromosome 1(p36.13-p34.3)  People with D antigen are Rh positive and those without antigen D are Rh negative  Unlike what obtains with the ABO blood group, anti-Rh (anti-D) is not normally found even in Rh-negative persons, unless they have had specific stimulation in the form of blood transfusion or 16 incompatible fetus in an Rh-ve woman. 15 January 2025  Rhesus Factor and its Clinical Application  An Rh-positive individual can receive blood from Rh-positive or Rh-negative individuals.  An Rh-negative individual, if transfused with Rh-positive blood, may not react or have a mild blood transfusion reaction at the first time but the body becomes sensitized.  If the individual receives subsequent Rh-positive blood, severe blood transfusion reactions usually occur. 17 15 January 2025  Rhesus Factor and its Clinical Application  Rh incompatibility may occur when a mother with Rh- blood is pregnant with an Rh+ child (who inherited Rh+ from the father), the mother may become sensitized during pregnancy or at delivery and her body will produce anti-Rh antibodies(IgG).  During subsequent pregnancy, the anti-Rh antibodies may cross the placenta and cause haemolytic disease in the fetus before birth. 18 15 January 2025  Anti-D Immunoglobulin  To prevent this disease, when any Rh incompatibility is detected, the mother receives an intramuscular injection of anti-D immunoglobulin(RhIG) e.g RhoGAM  Anternatal RhIG: at 28 weeks of gestation  Post natal RhIG: within 72 hours of birth of Rh +ve neonate to avoid the development of antibodies in the mother.  This reduces the risk of the disease from 16% to 0.1%.  Injection indicated in feto-maternal hemorrhage e.g RTA, abdominal trauma, obstetric procedure during pregnancy. 19 15 January 2025  Racial Distribution of Blood Groups  The red cell antigen that determine blood group are inherited. Thus racial differences exist. Race Blood Group Rh+ A B AB O English 45 8 3 44 83 Nigerians 24 21 3 52 95 Japanese 36 23 9 32 100 Scots 34 11 3 44 80 20 15 January 2025  ABO Blood Group& Blood Transfusion  The person who gives blood is called a donor while the one who receives the blood is the recipient.  While transfusing the blood, the antigen of the donor and the antibody of the recipient are considered.  The antibody of the donor and antigen of the recipient is not considered.  Compatibility is determined by blood grouping and cross-matching.  Crossmatching-patients plasma is matched with the cells of the donor and the donor plasma is matched with the cells of the patient.  Blood transfusion reactions occur when incompatible blood is transfused into an individual with consequent agglutination and lysis of the red blood cells.  Blood transfusion reactions can result in fever, shock, renal failure, and death 21 15 January 2025  ABO Blood Grouping/Typing  Indications for ABO Blood Grouping; Blood Donors Transfusion recipients Transplant Candidates and Donors Newborns Paternity testing 22 15 January 2025  Landsteiner’s Rule 1. A person does not have an antibody to his/her own antigen(If the RBC membrane contains a particular antigen, the serum of the individual lacks the antibody against that antigen). 2. Each person has an antibody to the antigen he/she lacks (if the RBC membrane lacks in an antigen, the serum of the individual contains naturally occurring antibodies against that antigen) N.B. The rules were defined about the ABO system and were used as the basis for ABO grouping. Not applicable to the Rhesus system 23 15 January 2025  ABO Typing  ABO typing involves both antigen typing and antibody detection.  The antigen typing is referred to as the forward typing  The antibody detection is the reverse typing/back typing/serum confirmation 24 15 January 2025  Forward Typing  The forward typing determines antigens on the patient's or donor's cells  Cells are tested with the antisera reagents (A &B).  Antiserum A contains anti-A and antiserum B contains anti-B  The antisera are made from monoclonal antibodies or hyper- immunized human sources. 25 15 January 2025  Forward Typing Procedure  One drop of antiserum A and B are placed at opposite end of a glass slide.  One drop of suspension of rbc is added to each antiserum.  The slide is rocked for 2 minutes and the mixtures are observed for clumping(agglutination) by naked eyes and by microscopy (to detect microagglutination) 26 15 January 2025  Results  If agglutination occurs with antiserum A only, the individual’s blood group is A  If agglutination occurs with antiserum B only, the individual’s blood group is B.  If agglutination occurs with both antisera A and B, the individual’s blood group is AB.  If agglutination does not occur with either antiserum A or B, the individual’s blood group is O 27 15 January 2025  Reactions with Antisera Reagents Anti Serum A Anti Serum B ABO Blood Group + 0 A 0 + B + + AB 0 0 O 28 15 January 2025  ReverseTyping: Serum tested with Reagents A1Cells and B Cells A1Cells B Cells ABO Blood Group + 0 B 0 + A + + O 0 0 AB 29 15 January 2025  Discrepancies in ABO typing  Results of forward and reverse typing must agree before reporting out blood type.  If forward and reverse do not agree, must identify cause of discrepancy.  If cannot resolve discrepancy, the result is reported as UNKNOWN and give group O blood N.B. In clinics, cross-matching is done before transfusion: mixing the serum of recipient and rbc of donor. 30 15 January 2025  Concept of Universal Donor and Recipient  Universal donor : A person who has blood group O,Rh D negative and is therefore able to serve as donor to any other group in the ABO system.  Universal recipient: A person who has blood group AB,Rh D positive and is therefore able to receive blood from any other group in the ABO system 31 15 January 2025  ABO Inheritance Patterns  The A and B genes found on chromosome 9  An individual inherits one gene (allele) from the father and one from the mother  The two co-dominant alleles are A or B  The O gene is recessive and only expressed when it is inherited from both father and mother. 32 15 January 2025  Homozygosity/Heterozygosity & ABO Inheritance  Homozygous: alleles are the same for any given trait on both chromosome (genotype A/A)  Heterozygous: alleles for a given trait are different on each chromosome (genotype A/B or A/O)  A/A parent can only pass along A gene  A/O parent can pass along either A or O gene  B/B parent can only pass along B gene  B/O parent can pass along either B or O gene  O/O parent can only pass along O gene  AB parent can pass along either A or B gene 33 15 January 2025  ABO Phenotypes and Genotypes  A phenotype consists of only those traits or antigens that can be directly typed.  Genotype is the sum of all genes a person has inherited within a blood group system Phenotype Possible Genotype A AA or AO B BB or BO AB AB O OO 34 15 January 2025  AO Mother & BO Father Father's Genes Mother's Genes B O A AB AO O BO OO 35 15 January 2025  AA Mother & BB Father Father's Genes Mother's Genes B B A AB AB A AB AB 36 15 January 2025  AA Mother & BO Father Father's Genes Mother's Genes B O A AB AO A AB AO 37 15 January 2025  AA Mother & OO Father Father's Genes Mother's Genes O O A AO AO A AO AO 38 15 January 2025  AO Mother & OO Father Father's Genes Mother's Genes O O A AO AO O OO OO 39 15 January 2025  AB Mother & OO Father Father's Genes Mother's Genes O O A AO AO B BO BO 40 15 January 2025  Further Reading  https://en.wikipedia.org/wiki/ABO_blood_group_system  https://en.wikipedia.org/wiki/Rh_blood_group_system  https://www.nhs.uk/conditions/blood-groups  https://www.webmd.com/a-to-z-guides/blood-types-what-to- know  https://emedicine.medscape.com/article/1731198-overview 41 15 January 2025