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Blood Bank Test 2 > ABO General Information > Flashcards

ABO General Information Flashcards

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1
Q

Who discovered the ABO system?

A

Karl Landsteiner

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2
Q

What are the characteristics of ABO antibodies?

A

Usually IgM
Capable of agglutinating RBCs without enhancement
Can activate complement

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3
Q

What are the blood types in order of frequency in the population?

A

O (45%)
A (41%)
B (10%)
AB (4%)

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4
Q

What is the H gene? What protein does it code for?

A

The H genes acts as an acceptor of sugars, delivered by transferase enzymes produced by A and B genes; codes for L-fucosyltransferases

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5
Q

What is the result of inheriting the hh gene?

A

Bombay or H null phenotype; no normal expression of ABO antigens (no or altered L-fucosyltransferase produced)

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6
Q

If a person’s genotype is O, what is there phenotype?

A

H (the person has no A or B genes but they still have the H antigen)

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7
Q

What is the immunodominant sugar of the H gene?

A

L-fucose

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8
Q

Which genotype has the highest concentration of H antigen? List other antigens in order of quantity of H

A

O > A2 > A2B > B > A1 > A1B

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9
Q

What does the A phenotype code for?

A

N-acetylgalactosaminyltransferase (runner)

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10
Q

What does the A phenotype tranfer to the H antigen?

A

N-acetylgalactosamine (GalNAc)

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11
Q

What is the immunodominant sugar of the A phenotype?

A

N-acetylgalactosamine (GalNAc)

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12
Q

What does the B phenotype code for?

A

D-galactosyltransferase (runner)

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13
Q

What does the B phenotype transfer to the H antigen?

A

D-galactose (Gal)

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14
Q

What is the immunodominant sugar of the B phenotype?

A

D-galactose (Gal)

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15
Q

What does the AB phenotype code for?

A

N-acetylgalactosaminyltransferase and

D-galactosyltransferase (runners)

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16
Q

What are the immunodominant sugars of the AB phenotype?

A

N-acetylgalactosamine (GalNAc)
and
D-galactose (Gal)

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17
Q

Since AB blood types cannot attach both sugars to the H antigen, which sugar attaches more successfully?

A

B (D-galactose (Gal))

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18
Q

Define isoagglutinins

A

antibodies that react with some members of the same species.

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19
Q

How long does it take newborns to develope isoagglutinins?

A

3 to 6 weeks

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20
Q

Define non-red cell stimulated (NRCS)

A

replaced the term “naturally occurring”. Describes red blood cell antibodies that are not formed through direct stimulation by a red blood cell antigen.

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21
Q

Define glycotransferase

A

enzymes which facilitate the transfer of carbohydrate; ABO blood group genes code for glycotransferases, which are specific for an immunodominant sugar (this completes the antigenic determininant)

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22
Q

Which gene in the ABO system is an amorph? What is an amorph?

A

O; a silent gene

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23
Q

Where is the ABO locus found?

A

The long arm of chromosome 9

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24
Q

Define the Bombay phenotype

A

phenotype that results from lack of the H gene (i.e. the person is hh).

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25
How do people with the Bombay phenotype forward group?
O Anti-A: 0 Anti-B: 0 Anti-H: 0 (people with O phenotype will be Anti-H: 4+)
26
How do people with the Bombay phenotype reverse group?
O A cells: 4+ B cells: 4+ (same as O phenotype)
27
Why is the Bombay phenotype highly incompatible with an O donor?
Anti-H is present in the serum of Bombay indiviuals
28
What does Bombay sera contain?
Anti-A Anti-B Anti-A,B Anti-H
29
Which plant lectin is used to type for Bombay? What will the plant lectin reation be for the Bombay phenotype?
Ulex europaeus; 0 (because it is an anti-H lectin, and the Bombay phenotype has not H antigen)
30
Describe the Para-Bombay phenotype
these individuals can have H, A, and B substances in their secretions while their red cells have no A, B, or H sugars (or minute amounts). Due to mutant H or FUT1 locus, but normal secretor genes. Para Bombay serum is anti-H.
31
What causes the Cis-AB phenotype?
Occurs of unequal crossing over of genetic information; most commonly A and B (documented in cases of disputed paternity)
32
How long does it take for adult levels of A and B antigens to form?
2-4 years
33
How are the A and B antigen formed?
formed by a complex interrelationship between the H/h genes and the ABO genes coding for glycotransferases to place terminal sugars onto precursor substance on type II chain.
34
What type of antibodys are NRCS?
IgM (some IgG or IgA may be present)
35
What are the characteristics of IgM?
Reacts best at room temp or below Can activate complement Saline agglutinins
36
What bacteria is hypothesized to stimulate A and B antigens?
E. coli
37
IgG (the immune form of ABO antibodies) is stimulated by
transfusion pregnancy other sources of incompatible RBCs
38
Which immunoglobulin is naturally occuring? Which is stimulated?
IgM- naturally occuring | IgG- stimulated
39
In what percent of the population if Anti-A1 found?
80%
40
What cells does Anti-A1 react with?
reacts with A1 cells, but not with A2 cells (can be removed with A2 cells on exhaustive adsorption)
41
In what percent of the population is Anti-Acommon found?
20%
42
What does Anti-Acommon react with?
both A1 and A2 cells
43
What plant lectin is used to differentiate beween A1 and A2 cells?
Dolichos biflorus
44
Where is anti-A,B found?
In sera of group O people
45
Anti-A, Anti-B, and Anti-A,B are usually what type of immunoglobulin?
IgM
46
In type O people, anti-A,B is more likely what immunoglobulin?
IgG
47
Anti-H is found in the sera of what group of people?
A1 and A1B people (weakly reactive) | Bombay or Oh (strongly reactive)
48
Which group of people may fail to recognize "self" and make antibody to H?
A1 and A1B
49
Define secretor
a person who has inherited the Se gene in single or double dose. Such people secrete ABH substances in their body fluids.
50
Define forward grouping
test in which unknown RBCs are mixed with antisera of know specificity to determine presence or absence of antigens on the red blood cells.
51
Define reverse grouping
eroligical test in which serum containing unknown ABO antiboy(ies) is tested with red blood cells of known ABO group
52
What are the most common phenotypes frequencies?
O A B AB
53
Leukemia can result in
the loss of antigens
54
Carcinomas can result in
reduction of antigen strength (by production fo BGSS) This has been corrected now because we wash the cells
55
Hypogammaglobulinemia, lymphocytic anemia, and non Hodgekin lymphomo may result in
decreased antibodies
56
What percent of the population are secretors?
72%
57
Zz is a hypothetical gene that controls
the prescence of the H antigen on RBCs (failure to inhert at least 1 Z gene is extremely rare)
58
What are the most common subgroups of a (99%)
A1 (80%) | A2 (20%)
59
A1 reacts with
anti-A | anti-A1
60
A2 reacts with
anti-A | NOT anti-A1
61
A2 and A2B people produce what in there serum?
anti-A
62
Anti-A1 is considered clinically insignificant. Why?
It is nonreactive at body temperature (rare expection that do react at body temperature are clinically significant)
63
Rare A subgroups
Aint, A3, Ax, Am, Ael, Aend, Ay
64
Rare B subgroups
B3, Bx, Bm, and Bel
65
Age, youth, hypogammaglobulinemia, immunosuppresion, bone marrow transplants, and stomach/pancrease cancer patients are all causes of
Weak or Missing Antibodies
66
How do you correct for weak or missing antibodies?
Optimize reverse group (incubate) | Include autocontrol or group O screening to rule out autoantibodies or alloantibodies
67
The weakining of subgroups or A and B due to leukemia can cause
Weak or absent antigens
68
Define Panagglutination
the ability of a particular serum to agglutinate all or almost all cells in a particular population.
69
How would you troubleshoot unexpected cold-reactive antibodies?
Collect a new specimen, prewarm, and keep at 37 degrees for all testing (wash cells)
70
How would you troubleshoot Unexpected Cold-reactive Antibodies
Try a different set of reverse cells to see if the reaction disappears.

Blood Bank Test 2 (5 decks)

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