Duffy

Question 1

DUFFY BLOOD GROUP SYSTEM (_____)

ISBT#

Answer 1

008

Question 2

The Duffy blood group system was discovered in____ when a multi-transfused hemophiliac patient named_____ was found to have an antibody in his serum, which was later identified as_____.

The following year (____), another antibody,_____, was identified in the serum of a woman who had undergone three pregnancies.

Answer 2

1950

Mr. Duffy

anti-Fya

1951

anti-Fyb

Question 3

One of the major clinical significances of the Duffy system is its association with_____, as the_____ is recognized as the entry point for this parasite into red blood cells (RBCs).

Answer 3

Plasmodium vivax malaria

Fy6 epitope

Question 4

The absence of_________ in many individuals of West African descent confers resistance to P. vivax infection, making the _____phenotype an important evolutionary adaptation in malaria-endemic regions.

Answer 4

Fya and Fyb antigens (Fy[a−b−])

Question 5

The Duffy blood group antigens are encoded by the Duffy___ gene, located on____

Answer 5

(FY)

chromosome 1

Question 6

Phenotype
Fy(a+ b-)
Fy(a- b+)
Fy(a- b-)

Genes/ Antigens????

Answer 6

Fy^a
Fy^b
Fy

Question 7

Antigens
Fy^a
Fy^b
Fy

Phenotypes???

Answer 7

Fy(a+ b-)
Fy(a- b+)
Fy(a- b-)

Question 8

DUFFY ANTIGEN
● Identified on fetal red cells at____ weeks gestation

Answer 8

6

Question 9

Duffy Ag

T or F???
● Well developed at birth

Answer 9

True

Question 10

Duffy Ag

● ONLY FOUND ON

Answer 10

RED CELLS (in blood cells)
○ Not found on lymphocytes, monocytes etc.

Question 11

Duffy Ag

● Identified to be found in other body tissues:

Answer 11

➢ Brain
➢ Spleen
➢ Colon
➢ Thyroid
➢ Endothelium
➢ Thymus
➢ Lung
➢ Kidney cells

Question 12

● FyA & FyB Are destroyed by common proteolytic enzymes:

Answer 12

○ Ficin
○ Papain
○ Bromelin
○ Chymotrypsin
○ ZZAP

Question 13

Duffy Ag

Not affected by..

Answer 13

AEP (a-chymotrypsin at acidic pH)
Glycine acid EDTA

Question 14

Phenotype???
Antigen Expression
Antibody Reaction Strength

High expression of Fya
Strong reaction with anti-Fya antibodies

Answer 14

Fy(a+ba-)

Question 15

Phenotype???
Antigen Expression
Antibody Reaction Strength

High expression of Fyb
Strong reaction with anti-Fyb antibodies

Answer 15

Fy(a-b+)

Question 16

Phenotype???
Antigen Expression
Antibody Reaction Strength

Moderate expression of both Fya and Fyb
Weaker reaction compared to homozygous individuals

Answer 16

Fy(a+b+)

Question 17

Phenotype???
Antigen Expression
Antibody Reaction Strength

No Duffy antigen expression on RBCs
No reaction with anti-Fya or anti-Fyb antibodies

Answer 17

Fy(a-b-)

Question 18

Duffy blood type more common in whites

Answer 18

Fy (a+b+)

Question 19

Duffy blood type more common in blacks

Answer 19

Fy (a-b-)

Question 20

Antigenic determinant that is common to BOTH Fya and Fyb antigens

Answer 20

Fy3

Question 21

Common to Blacks

Answer 21

Fy4

Question 22

Result of interaction between Rh complex and Duffy glycoprotein;
unknown molecular structure

Answer 22

Fy5

Question 23

Used by Plasmodium vivax as a receptor to gain entry in the RBC

Answer 23

Fy6

Question 24

Inherited weak form of Fyb

Answer 24

Fx

Question 25

Unaffected by enzyme treatment

Answer 25

Fy345

Question 26

Affected by enzyme treatment

Answer 26

Fy6x

Question 27

The Duffy antibodies are predominantly____, which means they are____-reacting antibodies that react best at___C and are detected at the AHG (antihuman globulin) phase of testing.

Answer 27

IgG; warm; 37°C

Question 28

DUFFY ANTIBODIES ● IgG (majority) ○ Highly reactive at_____ ○ Increases strength with____

Answer 28

AHG phase LISS(potentiator)

Question 29

Dosage Effect

Answer 29

Stronger reaction in homozygous individuals (Fy[a+b-] or Fy[a-b+]); weaker in heterozygous individuals.

Question 30

• In white populations, most individuals are_____, so their antibody reactions may be weaker. • In Black populations, many individuals are____, which means they lack Duffy antigens completely and do not form anti-Fya or anti-Fyb naturally.

Answer 30

heterozygous Fy(a+b+) Fy(a−b−)

Question 31

are receptors for malaria parasite ■ Used Plasmodium knowlesi for study ● P . vivax cannot be cultured

Answer 31

○ Fya and Fyb

Question 32

2 types of receptors required for malarial parasites to enter RBC: ■________- Duffy independent ■________- Fy6 antigen

Answer 32

Attachment receptor Invasion receptor