Knowledge Check • The Blood Project

Duffy-null associated neutrophil count (DANC) is associated with a polymorphism in what gene?

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Atypical chemokine receptor 1 (ACKR1)

What blood group is equivalent to ACKR1 on red blood cells?

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Duffy

Duffy was named in 1950 after:

a

The physician who discovered it

b

The patient in whom it was discovered

c

None of the above

True or false: on average, white blood cell counts are lower in people with African ancestry compared to Caucasians.

a

True

b

False

True or false: all individuals who are Duffy null have neutropenia.

a

True

b

False

About 10%

Which statement(s) is/are true concerning individuals with DANC:

a

Asymptomatic

b

Increased risk of infection

c

Protection against malarial infection

d

Increased risk of anemia and/or thrombocytopenia

Which statement(s) is/are true concerning expression of Ackr1 in Duffy-null individuals (i.e., those with DANC):

a

Loss of expression in RBCs and endothelial cells

b

Selective loss of expression in RBCs

c

No loss of expression in RBCs or endothelial cells

What is the favored mechanism for neutropenia in DANC?

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Reduced sink function on part of RBCs, resulting in increased circulating levels of cytokines which then egress into tissues leading to lower absolute neutrophil counts.