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Boards.CP.Blood Bank > ABO & Carbohydrate Ags > Flashcards

ABO & Carbohydrate Ags Flashcards

(58 cards)

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1
Q

ABO, Lewis, H, I and i are all what type of antigens?

A

Carbohydrate

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2
Q

Carbohydrate antigens are affected by genes that encode for what?

A

enzymes

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3
Q

Genes for protein antigens encode for what?

A

Structural proteins

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4
Q

Carbohydrate Vs. Protein Antigens:

-Naturally occuring

A

Carbohydrate

*Antibodies acquired only after exposure to products containing antigens

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5
Q

Carbohydrate Vs. Protein Antigens:

-Antibody type (IgG/IgM)

A

Carbohydrate - IgM

Protein - IgG

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6
Q

Carbohydrate Vs. Protein Antigens:

-Temperature

A

Carbohydrate - RT

Protein - 37 degrees

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7
Q

Carbohydrate Vs. Protein Antigens:

-“agglutinating” vs. “coating”

A

Carbohydrate - Agglutinating

Protein - Coating

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8
Q

Carbohydrate Vs. Protein Antigens:

  • React at AHG phase
  • React at IS phase
A

Protein - AHG phase

Carbohydrate - IS phase

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9
Q

How are H antigens made?

A

Type 1 and Type 2 precursor carbohydrates by the enzyme products of the:

  • H (FUT1) genes
  • Se (FUT2) genes
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10
Q

In secretions (saliva, tears) and in plasma, Type __ chains are converted into H antigen by _____ of the ____ gene product.

A
  • Type I
  • Fucosylation
  • Se (FUT2)
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11
Q

On the surfaces of RBC, Type __ chains are converted into H antigen by _____ of the ____ gene product.

A
  • Type 2
  • Fucosylation
  • H (FUT1)
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12
Q

Fucosyltransferase 1/2 (FUT1/2) adds _____ to type 1/2 chains at the terminal _______.

A
  • Fucose

- Galatacose

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13
Q

Se (“secretor”) gene (FUT2) frequency.

A

80%

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14
Q

H gene gene (FUT1) frequency.

A

virtually 100%

*Bombay = hh

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15
Q

T/F: H antigen is required before A and/or B can be made on RBCs or in Secretions.

A

True

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16
Q

Lewis antigens are made from type __ precursor by the enzyme product of _____ gene.

A
  • Type I (Secretor)

- Le (FUT3) gene

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17
Q

Secreted Le(b) and Le(c) are receptors for what?

A
  • Norwalk virus

- H. pylori

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18
Q

Le(a) is the epitope for what?

A

CA19-9

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19
Q

The A & B antigens are made from the __ antigen by the enzyme products of the ___ gene.

A
  • H antigen

- ABO gene

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20
Q

How is the A antigen formed?

A
  • A allele encodes N-acetyl-galactosaminyl transferase

- Adds N-acetyl galactosamine (NAG/Gal-NAc) to H

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21
Q

How is the B antigen formed?

A
  • B allele encodes Galactosyl transferase

- Adds D-galactose (GAL) to H

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22
Q

T/F: The O allele does not encode a functional protein.

A

True

-Group O RBCs contain abundant unaltered H antigen

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23
Q

The I and i antigens are epitopes within the ___ antigens

A

ABH

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24
Q

What represent the i antigens?

Study These Flashcards
A

Unbranched type 1 and 2 oligosaccharides

25
What represents the I antigens?
Branched type 1 and 2 oligosaccharides
26
Which antigen (I or i) increases with age?
I (branched oligosaccharides) *Adults have mostly I antigen
27
Which antigen (I or i) predominates in neonates and cord blood?
i (Unbranched oligosaccharides)
28
What situation might cause a resurgence of i?
High red cell turnovers states
29
Increased postnatal i antigen expression is characteristic of what syndromes? (2)
- Congenital dyserthropoietic anemia (CDA) type II | - Blackfan-Diamond syndrome
30
As more A or B antigen is made, less H remains. | -Levels of H antigen (decreasing order)
O>>A2>B>A2B>A1>A1B
31
What chromosome are the A, B, and O alleles on?
Chr9 (long arm; q)
32
When do ABO antigens 1st appear? | What age do they reach adult levels?
- Fetal RBCs at 6 weeks gestation | - age 4
33
Besides RBCs, where else are ABO antigens expressed? (7)
- Platelets - Endothelium - Kidney - Heart - Lung - Bowel - Pancreas
34
What antibodies are produced in a person with type O blood? (3)
IgM anti-A and Anti-B | -IgG anti-AB (can cause Mild ABO related HDFN)
35
What genotypes produce the A blood group?
AA or AO genotype
36
T/F: A1 cells express more A substance than A2.
True
37
What percentage of blood group A individuals have the A1 phenotype?
80%
38
A1 and A2 cells can be distinguished by the strength of reaction with what? (3)
- Anti-A1 reagent (serum of group B) - Dolichos biflorus lectin (Anti-A1 activity) - Ulex europaeus (H activity; A2>A1)
39
What is the most common blood group across all racial lines?
Group O
40
The B blood group results from which genotypes?
BB or BO genotype
41
The AB blood group results from what genotype?
AB genotype
42
How is the Bombay phenotype made?
h gene (an amorph) is inherited instead of H - No H antigen produced in blood - Forms anti-H (DANGEROUS)
43
T/F: The se gene is an amorph.
True
44
What % of the population are non-secretors?
20% (homozygous for se/se)
45
What must be present for Le(b) to be made?
Se and Le
46
T/F: Though Lewis antigen is synthesized on free type I precursor substance, it becomes passively adsorbed onto RBC surfaces.
True
47
The Lewis type cannot be reliably determined until what age?
2 years old
48
What is the most common Lewis Phenotype?
Le(a-b+) (both whites and blacks)
49
What Le phenotype is seen more often in blacks than whites.
Le(a-b-) (blacks 23%; whites 6%)
50
When are ABO Antibodies first detected? | When do they reach adult titers?
- Infants by 3-6 months | - 2 years old
51
ABO incompatibility results in what?
Complement activation and BRISK intravascular hemolysis
52
What group has Lewis antibodies?
Le(a-b-) (exclusively) | -Most commonly Blacks
53
T/F: Lewis (a-b+) people do NOT make Le(a) antibodies.
True
54
Lewis Antibodies are nearly always (IgG or IgM).
IgM (Insignificant)
55
Anti-I antibodies are associated with what type of infection?
Mycoplasma pneumoniae
56
Anti-i antibodies are associated with what type of infection?
EBV
57
The rare significant Lewis antibody is always what?
Anti-Le(a)
58
Why are Lewis antibodies generally insignificant?
- Transfused RBCs shed their Lewis antigens and acquire the Lewis phenotype of the recipient - Antibodies are quickly absorbed by free serum Lewis antigens

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