[4] CHAPTER II LESSON 2

Question 1

2Represents phenotypes that show weaker variable serologic reactivity with the commonly used human polyclonal anti-A, anti-B, and anti-AB reagents.

Answer 1

ABO SUBGROUPS

Question 2

The weaker serologic reactivity of ABO subgroups is attributed to the decreased number of [?] on their red cells.

Answer 2

A and B antigen sites

Question 3

In 1911, [?] descried two different A antigens based on reactions between group A RBCs and anti-A and anti-A1.

Answer 3

von Dungern

Question 4

Cause discrepancies in [?].

Answer 4

ABO testing and cross matches

Question 5

Group A RBCs that react with both [?] are classified as A1

Answer 5

anti-A and anti-A1

Question 6

Those that react with [?] and not anti-A1 are classified as A2.

Answer 6

anti-A

Question 7

Classification into A1 and A2 cells account for [?] of all group A individuals

Answer 7

99%

Question 8

BLOOD GROUP A1 ANTI-A REAGENT

Answer 8

+

Question 9

BLOOD GROUP A1 ANTI-A1 LECTIN REAGENT

Answer 9

0

Question 10

BLOOD GROUP A2 ANTI-A REAGENT

Answer 10

+

Question 11

BLOOD GROUP A2 ANTI-A1 LECTIN REAGENT

Answer 11

+

Question 12

Differences in the precursor oligosaccharide chains

Answer 12

↓ Number of antigen sites

Question 13

Subtle differences in transferase enzymes

Answer 13

↓ Amount of transferase enzyme

Question 14

Formation of anti-A1, in a percentage of some subgroups

Answer 14

↓ Amount of branching

Question 15

The immunodominant sugar on both A1 and A2 RBCs is

Answer 15

N-actylD-galactosamine

Question 16

Differentiation of A1 and A2 phenotypes can be determined by using a reagent made from the seeds of the plant

Answer 16

Dolichos biflorus

Question 17

is found in greatest concentration on the RBCs of O individuals

Answer 17

H antigen

Question 18

Reactivity of anti-H antisera or anti-H lectin with ABO blood groups:

Answer 18

O > A2 > B > A2B > A1 > A1B

Question 19

• agglutinates A1 or A1B

Answer 19

1. Dolichos biflorus

Question 20

agglutinates B cells

Answer 20

2. Bandeiraea simplicifolia

Question 21

• agglutinates O cells (H specificity) and other ABO blood groups depending on the amount of H antigen available

Answer 21

3. Ulex europaeus

Question 22

In accordance with Landsteiner’s rule for expected ABO antibodies, sera from group O and B individuals contain

Answer 22

anti-A antibodies.

Question 23

The anti-A produced by group O and B individuals can be separated by adsorption and elution techniques into two components:

Answer 23

anti-A and anti-A1

Question 24

is specific for the A1 antigen and does not agglutinate A2 red cells

Answer 24

Anti-A1

Question 25

The optimal reactivity of this antibody is at room temperature or lower.

Answer 25

AntiA1

Question 26

is not considered clinically significant for transfusion purposes

Answer 26

AntiA1

Question 27

becomes a concern when it causes problems with ABO phenotyping results and incompatible crossmatches on immediate spin

Answer 27

AntiA1

Question 28

does not exist because the A2 phenotype possesses the same A antigens as A1 phenotype but in reduced quantities.

Answer 28

Anti-A2

Question 29

Individuals with A1 phenotype do not respond immunologically when exposed to

Answer 29

A2 red cells.

Question 30

A1 Anti A

Answer 30

4+

Question 31

A1 Anti A

Answer 31

0

Question 32

A1 Anti B

Answer 32

4+

Question 33

A1 AntiA,B

Answer 33

4+

Question 34

A1 Anti A1

Answer 34

4+

Question 35

A1 Common

Answer 35

anti-B

Question 36

A1 Unexpected

Answer 36

None

Question 37

A1 Subs. Present in the saliva of secretors

Answer 37

A, H

Question 38

A1 Number of antigen sites RBC x 103

Answer 38

810-1170

Question 39

A2 Anti A

Answer 39

4+

Question 40

A2 Anti B

Answer 40

0

Question 41

A2 AntiA,B

Answer 41

4+

Question 42

A2 Anti A1

Answer 42

0

Question 43

A2 Common

Answer 43

anti-B

Question 44

A2 Unexpected

Answer 44

anti- A1 (1%-8% of cases)

Question 45

A2 Subs. Present in the saliva of secretors

Answer 45

A, H

Question 46

A2 Subs. Present in the saliva of secretors

Answer 46

A, H

Question 47

A2 Number of antigen sites RBC x 103

Answer 47

240-290

Question 48

Subgroups weaker than [?] occur infrequently and are most often recognized through an ABO discrepancy (unexpected reactions in the forward and reverse grouping).

Answer 48

A2

Question 49

These subgroups of A make up [?] of those encountered in the laboratory and therefore are mainly of academic interest.

Answer 49

1%

Question 50

can be utilized to subdivide A individuals into A3, Ax, Aend, etc.

Answer 50

Secretor studies, adsorption-elution tests, and molecular testing

Question 51

Occasionally, weak subgroups of [?] may present practical problems, for example, if an Ax donor was mistyped as group O and was transfused to a group O patient.

Answer 51

A

Question 52

This is potentially dangerous because the group O patient possesses [?], which agglutinates and lyses Ax RBCs, causing rapid intravascular hemolysis.

Answer 52

anti-A,B

Question 53

Characteristics: 1. Decreased number of [?] (resulting in weak or no agglutination with human polyclonal anti-A) 2. Varying degrees of agglutination by [?] 3. Increased variability in the detectability of [?] resulting in strong reactions with anti-H 4. Presence or absence of [?] in the serum

Answer 53

A antigen sites per RBC human anti-A,B H antigen anti-A1

Question 54

Weak A phenotypes can be serologically differentiated using the following techniques: 1. Forward grouping of [?] with anti-A, anti-A,B and anti-H 2. Reverse grouping of [?] and the presence of [?] 3. Adsorption-elution tests with [?] 4. Saliva studies to detect the presence of [?]

Answer 54

A and H antigens ABO isoagglutinins; antiA1 anti-A A and H substances

Question 55

Additional special procedures such as [?] for detecting the A enzyme that can be performed for the differentiation of weak subgroups.

Answer 55

molecular testing, serum glycosyltransferase studies

Question 56

Absence of a disease process should be confirmed before subgroup investigation because [?] are altered in various malignancies and other hematologic disorders.

Answer 56

ABH antigens

Question 57

Weak A subgroups can be distinguished as:

Question 58

Characteristically demonstrate a mixed field pattern of agglutination with anti-A and anti-A,B reagents.

Answer 58

A3 RBCs

Question 59

The estimated number of A antigen sites is approximately 35,000 per RBC.

Answer 59

A3 RBCs

Question 60

Weak a-3-N-acetylgalactosamine activity is detectable in the serum.

Answer 60

A3 RBCs

Question 61

Anti-A1 may be present in serum of A3 individuals, and A substance is detected in the saliva of A3 secretors.

Answer 61

A3 RBCs

Question 62

Characteristically not agglutinated by anti-A reagent but do agglutinate with most examples of anti-A,B

Answer 62

Ax RBCs

Question 63

Characteristically not agglutinated by anti-A reagent but do agglutinate with most examples of anti-A,B

Answer 63

Ax RBCs

Question 64

Estimated number of A antigen sites is approximately 4,000 per RBC

Answer 64

Ax RBCs

Question 65

Anti-A can be adsorbed and then eluted from Ax cells without difficulty.

Answer 65

Ax RBCs

Question 66

Transferase: not detectable in the serum or in the RBC membranes of Ax individuals

Answer 66

Ax RBCs

Question 67

individuals almost always produce anti-A1 in their serum

Answer 67

Ax RBCs

Question 68

Routine secretor studies detect the presence of only H substance in Ax secretors

Answer 68

Ax RBCs

Question 69

contain A substance detectable only by agglutination/ inhibition studies using Ax RBCs as indicators

Answer 69

Ax RBCs

Question 70

Caution should be used in interpreting results of secretor studies using Ax indicator cells and anti-A, because not all Ax cells are agglutinated by anti-A.

Answer 70

Ax RBCs

Question 71

Characteristically demonstrate mixed-field agglutination with antiA and anti-A, B, but only a very small percentage of the RBCs (10% or less) agglutinate.

Question 72

Estimated number of A antigen sites on the few agglutinable RBCs is approximately 3500 per RBC, whereas no detectable A antigens are demonstrated on RBCs that do not agglutinate.

Question 73

Secretor studies detect the presence of only H substance in the saliva of Aend secretors. AntiA1 is found in some Aend sera.

Answer 73

Aend RBCs

Question 74

The phenotypes of Afinn and Abantu are considered by some investigators to represent variants of the Aend subgroup

Answer 74

Aend RBCs