Blood Groups and Blood Transfusion Flashcards
How many blood groups are there?
- 4
What are the 4 main blood groups (we need to know), without accounting for the rhesus antigen?
- A - B - AB - O
Self antigens are what is present on all human cells to ensure the body does not attack itself (hypersensitivity type II). What antigens are present on the surface of RBCs on in each blood type?
- A = A antigen
- B = B antigens
- AB = A and B antigens
- O = no antigens
Self antigens are what is present on all human cells to ensure the body does not attack itself (hypersensitivity type II). If incorrect blood is transfused what, causing a type II hypersensitivity, what anti-bodies in the blood of each blood type are present to facilitate this immune response?
- A = anti B antibodies
- B = anti A antibodies
- AB = none
- O = anti A and B antibodies
Why would an individual with blood type A have anti B antibodies in plasma?
- because B antibodies would be recognised as foreign
- the body would then attack blood with B antigens
What are the 3 main components of blood antigens?
1 - fucose (sugar)
2 - galactose (sugar)
3 - N-acetylgalactosamine (sugar)
What is the ABO blood group system?
- blood group system including A, B, AB or O
- most clinically relevent
What is the Rh blood group system?
- blood group indicating if patient has rhesus antigen
- can include + (with antigen) or - (without antigen)
What is the H substance, also referred to as antigen H?
- precursor for A and B antigens on blood
What is the H substance, also referred to as antigen H composed of?
- fucose attached to an oligosaccharide
How is the H substance, also referred to as antigen H made on the red blood cell?
- immature RBCs have nucleus and chromosomes
- chromosome 19 expresses fucose transferase
What enzyme is expressed on chromosome 19 that adds fucose to the oligosaccharide creating the H substance, also referred to as antigen H?
- fucose transferase
How does blood type A and B add to the H substance, also commonly known as H antigen to become A and B blood type?
- locus on chromosome 9 expresses an enzyme
In order for blood type A to form antigens it needs to add to the H substance, also commonly known as H antigen. It does this by adding to the fucose (H substance), what enzyme is expressed on chromosome 9 to facilitate this, and what is added to the fucose?
- N-acetylgalactosamine transferase
- adds acetylgalactosamine to fucose
What is common in the structure of all blood type antibodies?
- all begin as H substance (H antigen)
- all attached to RBCs by glycoprotein
- galactose attached glycoprotein
What is the structure of the A antigen present in blood group A patients?
- glycoprotein attached to RBC
- galactose
- fucose
- acetylgalactosamine
In order for blood type B to form antigens it needs to add to the H substance, also commonly known as H antigen. It does this by adding to the fucose (H substance), what enzyme is expressed on chromosome 9 to facilitate this, and what is added to the fucose?
- glycosyl-transferase
- adds galactose to fucose
What is the structure of the B antigen present in blood group B patients?
- glycoprotein attached to RBC
- galactose
- fucose
- galactose
How is chromosome 9 able to expresses for A, B or O antigens in the same person?
- each person has 2 copies of chromosome 9
- each person has gene allele for A, B or O
In patients with blood types A and B, would the gene expression on the allele on chromosome 9 be expressing A, B or O antigens from both mum and dads copy of the chromosomes?
- blood type A = A + O
- blood type B = B + O
- blood type AB = A + B
- blood type O = O + O
- the O is generally silent unless both parents have it
What are agglutinins?
- IgM antibodies
- IgM = pentameric
- pentameric = 5 subunits for binding
What is the role of IgM antibodies, also referred to as agglutinins in blood?
- bind to A or B antibodies
- anti B antibody = hates A
- anti A antibody = hates B
Do IgM antibodies, also referred to as agglutinins circulate in the plasma or are they attached to RBCs?
- circulate in plasma
IgM antibodies, also referred to as agglutinins circulating in the plasma can come into contact with the wrong blood, this is why they circulate, it increases the chances of identifying a problem with blood type if it is present. What can IGm binding to the wrong blood type do to the blood?
- agglutination also referred to as haemagglutination
What would cause agglutination also referred to as haemagglutination in blood types A and B?
- blood type A receives blood from blood group B
- blood type B receives blood from blood group A
Why would a patient with blood type A receiving blood from a patient with blood group B cause agglutination also referred to as haemagglutination?
- blood group A contain IgM anti-B antibodies in plasma
- IgM anti-B antibodies would bind the B antigens on RBCs
- B antigens are only present on B type RBCs
- IgM anti-B antibodies binding will cause agglutination
A patient with blood type A can receive blood from which patients?
- blood group A and O
A patient with blood type B can receive blood from which patients?
- blood group B and O