Chapter 6: The ABO Blood Group System (P)

Question 1

What is the most important blood grp system among all blood grps in transfusion practice?

Answer 1

The ABO system

Question 2

What is the characteristic of ABO blood grp system?

Answer 2

It is the only blood grp system in w/c people have Abs in their serum to Ags that are absent from their RBCs

Question 3

What is the result since Abs are present in the ABO blood grp system?

Answer 3

Due to these Abs, transfusion of incompatible ABO type may result in immediate lysis of donor’s RBCs

Question 4

What is the leading cause of death that is still present until today?

Answer 4

Transfusion of wrong ABO grps w/c results in hemolytic transfusion rxn fatalities reported by FDA

Question 5

What are the processes or principles present under routine ABO testing?

Answer 5

1) Forward grouping

2) Reverse grouping

Question 6

What is the principle of forward grouping?

Answer 6

The pt’s RBCs w/ commercial antisera

Question 7

What is the principle of reverse grouping?

Answer 7

The pt’s serum w/ commercial RBCs

Question 8

What are the routine rgnts used for ABO testing (in forward typing)?

Answer 8

1) Anti-A
2) Anti-B
3) Anti-D
4) Rh Control

Question 9

What are the routine rgnts used for ABO testing (in reverse typing)?

Answer 9

1) A1 cells
2) B cells
3) A2 cells: also available but not routinely used

Question 10

*What are the concepts for routine ABO testing?

Answer 10

1) Ags are present on the RBCs

2) Abs are present in the pt’s plasma / serum

Question 11

Answer the ff questions w/ regards to ABO frequencies in the given blood grp:

1) What is the frequency of ABO for white individuals?
2) What is the frequency of ABO for black individuals?

Given blood grp: O

Answer 11

1) 45%

2) 50%

Question 12

Answer the ff questions w/ regards to ABO frequencies in the given blood grp:

1) What is the frequency of ABO for white individuals?
2) What is the frequency of ABO for black individuals?

Given blood grp: A

Answer 12

1) 40%

2) 26%

Question 13

Answer the ff questions w/ regards to ABO frequencies in the given blood grp:

1) What is the frequency of ABO for white individuals?
2) What is the frequency of ABO for black individuals?

Given blood grp: B

Answer 13

1) 11%

2) 20%

Question 14

Answer the ff questions w/ regards to ABO frequencies in the given blood grp:

1) What is the frequency of ABO for white individuals?
2) What is the frequency of ABO for black individuals?

Given blood grp: AB

Answer 14

1) 4%

2) 4%

Question 15

What is the relationship bet forward and reverse typing?

Answer 15

Forward typing is inversely related to reverse typing

Question 16

Is reverse typing performed in infants? Why or why not?

Answer 16

No, because they do not have ABO Abs at birth

Question 17

Since reverse typing is not performed to infants, what is only performed?

Answer 17

Forward typing

Question 18

In reverse typing for infants, what is the sx used?

Answer 18

Cord blood

Question 19

Most Abs present in the cord blood serum are from whom?

Answer 19

From the mother (maternal)

Question 20

Reciprocal ABO Abs are what?

Answer 20

These are naturally occurring Abs

Question 21

*When are reciprocal ABO Abs fully developed?

Answer 21

These are fully developed at 3 - 6 mos after birth

Question 22

*Postulated role of bacteria

Question 23

*What is the predominant Ig present in ABO Abs?

Answer 23

IgM (pentamer)

Question 24

What is the main Ig present in anti-A (from a B person) and anti-B (from an A person)?

Answer 24

IgM

Question 25

Even if IgM is mainly present in anti-A and anti-B, what is the other Ig present in small quantities in anti-A and anti-B?

Answer 25

Small quantities of IgG

Question 26

*What are the Abs produced by O persons?

Answer 26

1) Anti-A 2) Anti-B 3) Anti-A,B

Question 27

What Ig is anti-A,B?

Answer 27

IgG

Question 28

True or False Anti-A,B is a combination of anti-A and anti-B

Answer 28

False, because anti-A,B is not a combination of anti-A and anti-B

Question 29

*What is the characteristic of anti-A,B?

Answer 29

It is a separate "cross-reacting" Ab

Question 30

*What are the fxns of ABO Abs?

Answer 30

1) To activate complement | 2) To produce strong direct agglutination rxns

Question 31

*At what temp are ABO Abs present (or stable?)?

Answer 31

Room temp (22 DC) or colder

Question 32

*What are the characteristics of the rgnts used in routine ABO testing?

Answer 32

1) Rgnt anti-A is used 2) Rgnt anti-B is used 3) Rgnt anti-A,B is used 4) Can be monoclonal antisera 5) Can be polyclonal antisera 6) Considered in routine blood bank testing

Question 33

Is rgnt anti-A,B routinely used? Why or why not?

Answer 33

It is not routinely used because commercial, monoclonal anti-A and anti-B can detect most weak A and B Ags

Question 34

What is the contribution of the work of Bernstein?

Answer 34

It is the 1st to demonstrate inheritance of ABO gene - one from both parents

Question 35

When is the work of Bernstein presented?

Answer 35

1924

Question 36

*What are the characteristics of inheritance by Mendelian genetics?

Answer 36

1) Codominant expression 2) O gene is considered an amorph 3) O phenotype can only be produced by 2 O genes (OO) 4) Phenotype vs Genotype

Question 37

Why is O gene considered an amorph?

Answer 37

Because there is no detectable Ag produced by the inheritance of this gene

Question 38

What is the corresponding phenotype of the given genotype? Given genotype: A1A1

Answer 38

A1

Question 39

What is the corresponding phenotype of the given genotype? Given genotype: A1A2

Answer 39

A1

Question 40

What is the corresponding phenotype of the given genotype? Given genotype: A1O

Answer 40

A1

Question 41

What is the corresponding phenotype of the given genotype? Given genotype: A2A2

Answer 41

A2

Question 42

What is the corresponding phenotype of the given genotype? Given genotype: A2O

Answer 42

A2

Question 43

What is the corresponding phenotype of the given genotype? Given genotype: A1B

Answer 43

A1B

Question 44

What is the corresponding phenotype of the given genotype? Given genotype: A2B

Answer 44

A2B

Question 45

What is the corresponding phenotype of the given genotype? Given genotype: OO

Answer 45

O

Question 46

What is the corresponding phenotype of the given genotype? Given genotype: BB

Answer 46

B

Question 47

What is the corresponding phenotype of the given genotype? Given genotype: BO

Answer 47

B

Question 48

ABH Ag formation results from what?

Answer 48

It results from the interaction of genes at 3 separate loci (ABO, Hh, and Se)

Question 49

*What is the characteristic of the genes that interact w/c results to ABH Ag formation?

Answer 49

These genes do not code for production of Ags but rather to produce sp glycosyltransferases that add sugars to a basic precursor substance

Question 50

What is the characteristic of H Ag?

Answer 50

It is the precursor structure on w/c the A and B Ags are made

Question 51

Where are H and Se genes present?

Answer 51

These are present on chromosome 19

Question 52

What is the relationship bet H and Se genes?

Answer 52

These are closely linked

Question 53

Se gene are inherited to form what?

Answer 53

To form the ABO Ags in secretions

Question 54

*At what age grp are A, B, and H Ags produced?

Answer 54

In fetal and adult life

Question 55

What is the percentage of Ags present in the RBCs of newborns in comparison to those found on adult RBCs?

Answer 55

25 - 50% of Ags of those that are found in adult RBCs

Question 56

What is the result since RBCs of newborns carry 25 - 50% of Ags to those found on adult RBCs?

Answer 56

Newborn rxns in the forward typing are weaker than those in adults

Question 57

When are ABO Ags fully expressed?

Answer 57

These are fully expressed at 2 - 4 yrs of age

Question 58

Are ABO Abs present until 3 - 6 mos?

Answer 58

No, these are not present until 3 - 6 mos

Question 59

Immunodominant sugars confer what?

Answer 59

These confer blood grp specificity

Question 60

What is the immunodominant sugar present to the given gene and Ag? Given gene and Ag: H

Answer 60

L-fucose

Question 61

What is the immunodominant sugar present to the given gene and Ag? Given gene and Ag: A

Answer 61

N-acetyl-D-galactosamine

Question 62

What is the immunodominant sugar present to the given gene and Ag? Given gene and Ag: B

Answer 62

D-galactose

Question 63

Where is ABO gene located?

Answer 63

It is located on chromosome 9

Question 64

What is the composition of ABO gene?

Answer 64

It consists of 7 exons

Question 65

*What is present at the ABO locus?

Answer 65

Diversity

Question 66

What are integral parts of the membranes of various cells?

Answer 66

ABH Ags

Question 67

Where can ABH-soluble Ags be found?

Answer 67

These can be found in all body secretions

Question 68

*ABH-soluble Ags w/c are present in secretions is dependent on what?

Answer 68

These are dependent on ABO and secretor genes inherited

Question 69

*Are nonsecretors possible to be dependent on ABO and secretor genes inherited?

Answer 69

Yes

Question 70

What are ABO subgrps?

Answer 70

These are phenotypes that show weaker variable serological reactivity w/ the commonly used human polyclonal anti-A, anti-B, and anti-A,B rgnts

Question 71

What type of rgnts are used routinely for ABO subgrps?

Answer 71

Monoclonal typing rgnts

Question 72

Who 1st described A subgrps?

Answer 72

von Dungen

Question 73

When are A subgrps 1st described?

Answer 73

1911

Question 74

What are the A subgrps?

Answer 74

1) A1 subgrp | 2) A2 subgrp

Question 75

At what aspects are A1 and A2 different?

Answer 75

1) Quantitative | 2) Qualitative

Question 76

Which is more generally common bet A subgrps and B subgrps?

Answer 76

A subgrps generally are more common > B subgrps

Question 77

*What is present among A subgrps?

Answer 77

Differences in conversion of H precursor substance

Question 78

*What are present at the ABO locus?

Answer 78

Effects of polymorphism

Question 79

*What is the result if forward grping rgnt anti-A is used?

Answer 79

It strongly agglutinates both A1 and A2 phenotypes

Question 80

What are the fxns of anti-A1 lectin rgnt (in connection w/ A subgrps)?

Answer 80

1) It is used in the differentiation of A1 and A2 phenotypes | 2) It agglutinates A1 (or A1B) cells but does not agglutinate A2 (or A2B cells)

Question 81

What are the exs of lectins used in BB?

Answer 81

1) Dolichos biflorus 2) Bandeiraea simplicifolia 3) Ulex europaeus

Question 82

What is the fxn of Dolichos biflorus?

Answer 82

It agglutinates A1 or A1B

Question 83

What is the fxn of Bandeiraea simplicifolia?

Answer 83

It agglutinates B cells

Question 84

What is the fxn of Ulex europaeus?

Answer 84

It agglutinates O cells (H specificity) and other ABO blood grps depending on the amt of H Ag available

Question 85

*Do the concentration of H Ag vary among blood grps?

Answer 85

Yes

Question 86

What is occasionally found in the serum?

Answer 86

Anti-H

Question 87

*What are the characteristics of H Ag?

Answer 87

1) It is a naturally occurring IgM cold agglutinin that reacts best below room temp 2) It can produce possible problems in Ab screening procedures 3) It can be detected via the use of anti-H lectin

Question 88

*What is the frequency of appearance of subgrps weaker than A2?

Answer 88

These occur infrequently

Question 89

*How are weak A subgrps most often recognized?

Answer 89

These are most often recognized through an ABO discrepancy (unexpected rxns in the forward and reverse grping)

Question 90

*varying expression of 4 characteristics

Question 91

Weak A subgrps can be distinguished as what?

Answer 91

1) A3 2) Ax 3) Aend 4) Am 5) Ay 6) Ael

Question 92

What are the characteristics of weak B subgrps?

Answer 92

1) These are very rare and less frequent > A subgrps 2) These are usually recognized by variations in the strength of the rxn using anti-B and anti-A,B antisera 3) These are the result of alternate alleles at the B locus

Question 93

*How many criteria are used for differentiation of weak B phenotypes?

Answer 93

5

Question 94

What can be used to characterize B subgrps as weak B subgrps?

Answer 94

Serologic techniques

Question 95

*What are the ff categories of B subgrps w/c are considered as weak B subgrps?

Answer 95

1) B3 2) Bx 3) Bm 4) Bel

Question 96

The Bombay phenotype is denoted as what?

Answer 96

Oh

Question 97

Who 1st reported the Bombay phenotype?

Answer 97

Bhende

Question 98

When did Bhende 1st reported the Bombay phenotype?

Answer 98

1952

Question 99

When did Bhende 1st reported the Bombay phenotype?

Answer 99

In Bombay, India

Question 100

What is the characteristic of hh genotype?

Answer 100

It is a very rare genotype

Question 101

How can genotype hh be produced?

Answer 101

Via the inheritance of a double dose of the h gene

Question 102

What are the characteristics of the Bombay phenotype?

Answer 102

1) It has no H Ag made 2) ABO genes can't be expressed 3) ABH genes can't be formed 4) RBCs are devoid of normal ABH Ags 5) It fails to react w/ anti-A, anti-B, and anti-H 6) It is an IgM Ab

Question 103

If only anti-A and anti-B antisera are used in RBC testing, the Bombay would phenotype as what blood grp?

Answer 103

O blood grp

Question 104

Where is anti-H occasionally found?

Answer 104

In the serum of A1 and A1B individuals

Question 105

The Bombay anti-H can often be potent and reacts strongly at what temp?

Answer 105

37 DC

Question 106

What are the fxns of the Bombay phenotype?

Answer 106

1) It can bind complement | 2) It can cause RBC lysis

Question 107

True or False Considerations for transfusions for Bombay phenotype must be present

Answer 107

True

Question 108

Who is/are the pt/s that can donate blood to a pt w/ Bombay phenotype?

Answer 108

Blood w/ Bombay phenotype is the only blood that is compatible

Question 109

Why should only a Bombay (donor) can donate blood to another Bombay (recipient)?

Answer 109

Because underlying molecular defect of the Bombay phenotype may be present

Question 110

What are the characteristics of Para-Bombay phenotypes?

Answer 110

1) These are rare phenotypes 2) RBCs are completely devoid of H Ags or 3) Small amts of H Ag are present

Question 111

*True or False ABH Ags and leukemias are associated

Answer 111

True

Question 112

Leukemias that are associated w/ ABH Ags demonstrates what?

Answer 112

Hypogammaglobulinemia

Question 113

Provide an ex of leukemia w/c is associated w/ ABH Ags

Answer 113

Chronic lymphocytic leukemia (or Chronic lymphoid leukemia) (CLL)

Question 114

*What are the diseases that can be present in ABH Ags and Abs in disease?

Answer 114

1) Other leukemias w/ chromosome 9 translocations 2) Any hemolytic disease inducing stress hematopoiesis (ex. thalassemia) 3) Acquired B phenomenon in grp A1 individuals

Question 115

What are the causes of the occurrence of unexpected rxns in the forward and reverse grping?

Answer 115

1) Problems w/ the pt's serum 2) Problems w/ the pt's RCs 3) Problems w/ both the serum and cells

Question 116

What is affected if problems w/ the pt's serum (as cause of occurrence of unexpected rxns in the forward and reverse grping) are present?

Answer 116

Reverse grping

Question 117

What is affected if problems w/ the pt's RCs (as cause of occurrence of unexpected rxns in the forward and reverse grping) are present?

Answer 117

Forward grping

Question 118

What is affected if problems w/ both the pt's serum and cells (as cause of occurrence of unexpected rxns in the forward and reverse grping) are present?

Answer 118

Forward and reverse grping

Question 119

What is the characteristic of ABO discrepancies?

Answer 119

These can appear as extra (+) or weak / missing rxns

Question 120

What must be done to ABO discrepancies if these are present prior to reporting a pt or donor's ABO grp?

Answer 120

These must be resolved

Question 121

What are the resolutions that can be done to common grp II discrepancies?

Answer 121

1) Enhancing weakly reacting Ags w/ room temp incubation 2) Pretreatment of RBCs w/ enzymes 3) In connection to acquired B Ag

Question 122

What are the diff categories of ABO discrepancies?

Answer 122

1) Grp I discrepancies 2) Grp II discrepancies 3) Grp III discrepancies 4) Grp IV discrepancies

Question 123

What are the resolutions for common grp III discrepancies?

Answer 123

1) In connection to effects of rouleaux | 2) In connection to effects of Wharton's jelly

Question 124

What are the resolutions for common grp IV discrepancies?

Answer 124

1) In terms for consideration of cold autoAbs 2) The pt's RBCs can be tested w/ Dolichos biflorus to confirm the presence of an ABO subgrp 3) Unexpected alloAbs in the pt's serum other than ABO isoagglutinins may cause a discrepancy in the reverse grping