Duffy Flashcards

1
Q

Duffy antigen location

A

Atypical chemokine receptor 1

Binds cytokines, especially IL-8; role in inflammation

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2
Q

Duffy gene (ACKR1) location

A

Chromosome 1q21-q22

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3
Q

How many Duffy antigens

A

5

Fya/b, Fy3, Fy5, Fy6

(Fy4 is obsolete)

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4
Q

Duffy phenotype frequency

Whites

A

Fy(a+b-): 20%
Fy(a+b+): 48%
Fy(a-b+): 32%
Fy(a-b-): 0%

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5
Q

Duffy phenotype frequency

African Americans

A

Fy(a+b-): 10%
Fy(a+b+): 3%
Fy(a-b+): 20%
Fy(a-b-): 67%

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6
Q

Duffy phenotype frequency

Asia

A

Fya is high prevalence

Fy(a+b-): 81%
Fy(a+b+): 15%
Fy(a-b+): 4%

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7
Q

Duffy antigen characteristics

A

Well developed at birth

Found on rbcs as well as endothelial cells, brain, colon, lung, spleen, kidney, etc

Weaken with storage

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8
Q

Duffy a/b antigen on treated RBCs

A

Destroyed by enzymes (bromelin, ficin, papain, pronase, a-chymotrypsin) and ZZAP

Resistant to trypsin

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9
Q

Fy(a-b-) in whites

A

Uncommon

Usually true null

No expression on RBCs or tissues

Can make anti-Fy3

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10
Q

Fy(a-b-) in blacks

A

Usually Arises from silencing mutation in the promoter region of the Fyb allele

Prevents expression on RBCs but still present on other tissues

Rarely make anti-Fyb or -Fy3

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11
Q

Anti-Fya/b

A

Usually IgG

Do not bind complement well

Show dosage

Clinically significant

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12
Q

Fy3, Fy5, Fy6 reactivity with enzyme treatment

A

Fy3 resistant
Fy5 resistant
Fy6 destroyed

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13
Q

Anti-Fy3

A

Found in Fy(a-b-) individual
Reacts as inseparable anti-Fya and -Fyb but enzymes don’t eliminate reactions

Acute and delayed HTRs

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14
Q

Anti-Fy5

A

Doesn’t react with Fy(a-b-) RBC or Rh null (regardless of their Duffy typing)

Delayed HTRs

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15
Q

Anti-Fy6

A

Not found in humans

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16
Q

Duffy receptor for which parasite

A

Plasmodium vivax