Unit 2 ABO Blood Group

Question 1

Who discovered the ABO blood group system?

Answer 1

Karl Landsteiner in 1901

Question 2

What is detected in reverse grouping?

Answer 2

Naturally occurring antibodies

Question 3

What antigen serves as the precursor for A and B antigens?

Answer 3

H antigen

Question 4

What antigens are present in a group B individual?

Answer 4

B antigen

Question 5

What antibodies are present in a group O individual?

Answer 5

Anti-A, Anti-B, Anti-AB

Question 6

What is the ISBT number for the ABO blood group?

Answer 6

ISBT 001

Question 7

What is the ISBT number for the Rh blood group?

Answer 7

ISBT 004

Question 8

Which blood type is the universal donor for red cells?

Answer 8

Blood group O

Question 9

Which blood type is the universal donor for plasma?

Answer 9

Blood group AB

Question 10

Which blood type is the universal recipient of red cells?

Answer 10

Blood group AB

Question 11

Which blood type is the universal recipient of plasma?

Answer 11

Blood group O

Question 12

What does forward typing detect?

Answer 12

Unknown antigen using known antibody

Question 13

What does reverse typing detect?

Answer 13

Unknown antibody using known antigen

Question 14

Why is reverse typing not required for babies?

Answer 14

They still have no antibodies

Question 15

Which phenotype is most likely to have an ulcer?

Answer 15

O phenotype

Question 16

Which phenotype is most likely to have gastric carcinoma?

Answer 16

A phenotype

Question 17

Which phenotype is most likely to have criminal instincts?

Answer 17

B phenotype

Question 18

What type of antibodies are ABO antibodies?

Answer 18

Naturally occurring IgM

Question 19

Which ABO antibody contains IgG?

Answer 19

Anti-AB

Question 20

What is required to activate complement in ABO antibodies?

Answer 20

Only one IgM molecule

Question 21

At what temperature do ABO antibodies react?

Answer 21

Room temperature or colder

Question 22

When does ABO antibody production begin?

Answer 22

At birth

Question 23

At what age do ABO antibody levels peak?

Answer 23

Between 5-10 years old

Question 24

Why do elderly individuals have lower antibody levels?

Answer 24

Thymus decreases in size with age

Question 25

What is the difference between genotype and phenotype?

Answer 25

Genotype is inherited, phenotype is expressed

Question 26

What does the H gene do?

Answer 26

Produces antigens on red blood cells

Question 27

What does the Se gene do?

Answer 27

Produces antigens in secretions

Question 28

What is the probable phenotype if a child inherits AO genotype?

Answer 28

A blood type

Question 29

Which genes are dominant in ABO inheritance?

Answer 29

A and B

Question 30

Which gene is recessive in ABO inheritance?

Answer 30

O

Question 31

What is the precursor for ABO antigens?

Answer 31

Paragloboside or glycan

Question 32

What is the immunodominant sugar for the H antigen?

Answer 32

L-fucose

Question 33

What is the immunodominant sugar for the A antigen?

Answer 33

N-acetyl-D-galactosamine

Question 34

What is the immunodominant sugar for the B antigen?

Answer 34

D-galactose

Question 35

Which blood group has the highest antigen sites?

Answer 35

A1 adult RBCs (810,000-1,170,000 sites)

Question 36

How many antigen sites does a B adult RBC have?

Answer 36

610,000-830,000 sites

Question 37

Which gene codes for the B antigen transferase?

Answer 37

B gene (α-3-D-galactosyltransferase)

Question 38

Why do AB individuals have more B antigens than A antigens?

Answer 38

B enzyme is more efficient in conversion

Question 39

Where are ABH antigens found?

Answer 39

RBCs, endothelial cells, platelets, lymphocytes, epithelial cells

Question 40

Where are ABH soluble antigens found?

Answer 40

All body secretions

Question 41

What is required for ABO typing in organ transplants?

Answer 41

Both ABO typing and HLA typing

Question 42

What is the genotype for a classical Bombay phenotype?

Answer 42

hh sese (no H antigen, no secretions)

Question 43

What enzyme does the Se gene code for?

Answer 43

α-2-L-fucosyltransferase

Question 44

What does agglutination inhibition testing check?

Answer 44

Secretion of ABH substances

Question 45

What is the sugar responsible for H specificity?

Answer 45

L-fucose

Question 46

What is the rare genotype that results in the Bombay phenotype?

Answer 46

hh

Question 47

Which gene is more common, H or h?

Answer 47

H gene is present in >99.99% of the population

Question 48

How can acquired B phenotype occur?

Answer 48

E. coli 086 infection removes N-acetyl from A antigen

Question 49

How does the Se gene affect secretions?

Answer 49

Allows A and B antigens to be present in secretions

Question 50

What is the primary structural difference between ABH antigens in RBCs and secretions?

Answer 50

RBC antigens are glycolipids/glycoproteins, secretions are glycoproteins

Question 51

What linkage is found in type 2 precursor chains (RBCs)?

Answer 51

β1 → 4 linkage

Question 52

What linkage is found in type 1 precursor chains (secretions)?

Answer 52

β1 → 3 linkage

Question 53

What is the function of α-2-L-fucosyltransferase?

Answer 53

Adds L-fucose to the precursor chain to form H antigen