The ABO Blood Group System

Question 1

Who discovered the ABO Blood group system

Answer 1

Karl Landsteiner

Question 2

When was the ABO blood group discovered

Answer 2

1901

Question 3

What were the original three blood groups

Answer 3

A B and C

Question 4

When was the AB blood group found?

Answer 4

1902

Question 5

Where is the ABO locus found?

Answer 5

Chromosome 9

Question 6

What type of antibody are the ABO antibodies?

Answer 6

IgM

Question 7

When was the A group subgroup found?

Answer 7

1930

Question 8

Why are ABO antibodies clinically significant

Answer 8

These are potent activators of complement

Question 9

Why are ABO antibodies not found in babies

Answer 9

Babies don’t have antibodies yet

Question 10

How do anti ABO antibodies come about?
(3)

Answer 10

You don’t have a gut microbiome yet

When gut flora develops, these have antigens which are similar to those found on rbcs

You develop antibodies to the antigen you don’t have

Question 11

What is significant about the group O antibodies

Answer 11

These antibodies (anti-A and anti-B) are IgG

Question 12

What is considered a major reaction in a transfusion

Answer 12

Wrong red cells

If you give A type blood to an O type person the individual kept producing anti A antibodies

Question 13

What is considered a minor reaction in a transfusion
(3)

Answer 13

Wrong plasma

If you give anti A plasma to an A red blood cell type

Anti A plasma will attack the person’s A rbcs but this will eventually run out

Question 14

What is Landsteiner’s rule?

Answer 14

This states that healthy individuals possess ABO antibodies to the ABO blood group antigens absent from their RBCs

Question 15

When were the ABO groups first put to practice?
(3)

Answer 15

1917

Transfused battlefield casualties in France

All were group O donations (universal donors)

Question 16

How would you describe the genetics of the ABO blood group system?

Answer 16

Blood group antigens are codominant

Question 17

What three genes influence the occurrence and location of ABO antigens?

Answer 17

ABO

H

Se

Question 18

What does the H gene control?

Answer 18

The presence or absence of the ABH antigens on the rbc membrane

If you have H you have antigens

If you dont have H you dont have rbc antigens

Question 19

What does the Se gene control?
(3)

Answer 19

The presence or absence of the ABH antigens in secretions

If you have Se then you will have ABH antigens in secretions

If you dont have Se then you will not have ABH antigens in secretions

Question 20

What are the two H gene alleles

Answer 20

H and h

Question 21

What is someone with the hh phenotype called?

Answer 21

The Bombay phenotype

Question 22

Where is the H gene located

Answer 22

Chromosome 19

Question 23

What is the h allele?

Answer 23

Its a damaged H allele -> very rare

Two hs will result in no antigens being expressed

Question 24

How does the H gene actually work?

Answer 24

It adds a L-Fucose

This acts as the substrate for ABO antigen

Question 25

Many people have an anti-H antibody, describe this

Answer 25

It's a cold antibody It's usually benign in the body at 37 degrees but when outside the body and it cools they can cause problems

Question 26

What acts as the basic precursor structure for the rbc antigens?

Answer 26

An oligosaccharide chain

Question 27

What is the oligosaccharide chain attached to?

Answer 27

Attached to a protein or lipid carrier molecule

Question 28

What does the H locus encode

Answer 28

An alpha 1,2 fucosyltransferase (FUT 1)

Question 29

What does the A locus encode

Answer 29

alpha 1,3 N-acetylgalactoaminyl transferase

Question 30

What does the A locus encode

Answer 30

alpha 1,3 N-acetylgalactoaminyl transferase

Question 31

What does the B locus encode

Answer 31

alpha 1,3 galactosyltransferase

Question 32

What does the Se gene encode?

Answer 32

An alpha 1,2 fucosyltransferase (FUT 2)

Question 33

By how much do the A and B genes differ from each other

Answer 33

They differ by 7 single base substitutions

Question 34

How does the O gene differ from the A gene

Answer 34

Differs by a single base deletion This results in the translation of a protein that does not produce an antigen

Question 35

What are the two A subtypes

Answer 35

A1 and A2

Question 36

How does A1 differ from A2

Answer 36

A1 enzyme is 5 to 10 times more active than the A2 enzyme

Question 37

What percentage of As are A1?

Answer 37

80% are A1 and 20% are A2

Question 38

Comment on the antibodies in A2 blood type

Answer 38

Some people have both anti-B and anti-A in their plasma

Question 39

What percentage of people are secreters of rbc antigens

Answer 39

Approximately 75%

Question 40

Write a note on the Bombay phenotype (5)

Answer 40

hh phenotype Only 2 families in Ireland have this You dont have any ABO or H on your rbcs Anti-A, Anti-B and anti-H Only autologous units or rare donor files can be used -> families can donate blood and it will be frozen

Question 41

What percentage of the Irish population is group O

Answer 41

55%+

Question 42

What percentage of the Irish population is group A

Answer 42

Approx 30

Question 43

What percentage of the Irish population is group B

Answer 43

Approx 10

Question 44

What percentage of the Irish population is group AB

Answer 44

Less than 5%

Question 45

What is considered the universal donor

Answer 45

Group O

Question 46

What is considered the universal recipient

Answer 46

Group AB

Question 47

What is considered the universal recipient

Answer 47

Group AB

Question 48

What is octaplas

Answer 48

A blood plasma product

Question 49

What specific type of O blood is given to women

Answer 49

O-

Question 50

What specific type of O blood is given to men

Answer 50

O+

Question 51

What types of plasma can be given to group O patients

Answer 51

B plasma -> Anti A plasma A plasma -> Anti B plasma O plasma (anti A and anti B plasma) Uniplas

Question 52

What type of plasma can be given to group B patients

Answer 52

Uniplas B group (anti-A plasma)

Question 53

What type of plasma can be given to group A patients

Answer 53

Uniplas A group (anti-B plasma)

Question 54

What plasma can be given to AB group

Answer 54

Uniplas

Question 55

Who can group O octaplas be given to?

Answer 55

Group O patients

Question 56

Group O can get platelets from who?

Answer 56

O A B AB

Question 57

Group B can get platelets from who?

Answer 57

B, A or AB

Question 58

Group A can get platelets from who?

Answer 58

A, B or AB

Question 59

Group AB can get platelets from who?

Answer 59

A or B

Question 60

Why do you rarely give group O platelets?

Answer 60

Anti A and B antibodies

Question 61

How does a mismatch occur? (2)

Answer 61

Wrong unit is administered Wrong sample is in the tube (wrong person's blood)

Question 62

What happens in a mismatch

Answer 62

Intravascular haemolysis Classical complement pathway activation Renal Failure