Blood Grouping

• the earliest known blood transfusion was in the 1600’s in battle where a king was given blood from a cow
• in 1875 Landois recorded incompatibilities between animals of different species
• in 1900 Landsteiner observed incompatibilities between humans
• Landsteiner discovered the ABO system in 1901 and received a noble prize for his work
• Blood Group A's serum agglutinates cells of group B
• agglutination refers to the clumping together of cells
• blood group B's serum agglutinates cells of group A
• group C (latter renamed group O)'s serum agglutinates both group A and B cells
• blood group is defined by the antigens on the red cell surface
• agglutination is due to antibodies within the serum
• blood group A has Anti-B antibodies
• blood group B has Anti-A antibodies
• blood group O has Anti-A and Anti-B antibodies
• blood group AB was discovered in 1902
• blood group AB does not agglutinate group A nor group B and there is no antibodies within its serum
• blood group is acquired by mendelian inheritance - 1 gene from each parent
• you are born with your blood group - which can be identified by antigens on the red cell surface (A/B)
• there are naturally occurring antibodies in serum (A/B) - you start developing them at 6 months old, their concentration peaks at 10 years and declines naturally with age
• antibodies in serum are stimulated by ingestion
• forward grouping states what antigens are on the surface of the cell
• reverse grouping is used to confirm forward grouping results and shows what antibodies are in the serum
• reverse blood grouping uses known antibodies to test for antigens within the serum
• The frequency of blood group O in Europe is :

  • 53% Scotland
  • 47% england
  • 43% mainland europe
• The frequency of blood group A in Europe is :

  • 33% Scotland
  • 42% england
  • 42% mainland europe
• The frequency of blood group B in Europe is :

  • 11% Scotland
  • 42% england
  • 42% mainland europe
• The frequency of blood group AB in Europe is :

  • 3% Scotland
  • 3% england
  • 4% mainland europe
• blood groups B and O appear to be less susceptible to severe infections - though to be related to the protection from anti-A antibodies
• ABO antibodies are usually IgM and cold-reacting (don't need to be at body temperature)
• abo antibodies do not cross the placenta
• ABO antibodies can bind complement nd create a complement cascade
• anti-A and anti-B are predominantly IgM but can be a mixture of anti-G, A, and M
• blood group O have anti-A anti-B and anti-AB (v small) antibodies
• anti-AB antibody is an antibody ion its own right - NOT a mixture of anti-A and anti-B although it is very small
• ABO antibodies are a mixture of Anti-G and M, or anti G A and M
• IgG can cross the placenta hence why anti-G is present
• the inheritance of ABO groups was first described by Bernstein in 1924
• there is 1 ABO gene inherited from each parent - this combination determines the antigens on the red cell surface
• 1 locus on each chromosome 9 has an A B or O gene
• the O gene is an amorph or silent allele as no antigen is produced
• genotype is the gene present and the phenotype is what he gene manifests as