MIDTERM LECTURE 1: KIDD BLOOD GROUP Flashcards
ISBT # of Kidd
009
how many antigens does Kidd have
3
who discovered Kidd blood group
Allen and colleagues, 1951
where was the Kidd antibody first found
serum of Mrs. Kidd, whose infant have HDFN
anti-Jka reacted with how many percent of Bostonians
77%
antithetical antibody of Jka
Jkb
null phenotype of Kidd
Jk(a-b-)
when was Jk(a-b-) described
1959
Jk3 is present in what individuals
have RBCs positive for Jka and Jkb
what happens when Jk(a-b-) individuals receive blood other than Jk(a-b-) donor
can cause HTR because of anti-Jk3
T or F:
Jk3 is present in Jka+ and Jkb+ individuals
T
why does Jk(a-b-) individuals produce anti-Jk3
since they do not have Jka and Jkb= absence of Jk3= Jk3 is foreign
why is Kidd considered as the most notorious blood group
cause of delayed HTR
T or F:
Jk antigens are well developed on the RBCs of neonates
T
Jka can be detected on fetal RBCs as early as
11 weeks
Jkb can be detected on fetal RVCs as early as
7 weeks
T or F:
Kidd antigens can cause HDFN
T
number of antigen sites per cell of Jk (a+b-)
14,000
T or F:
Kidd antigens are very immunogenic
F
(not that immunogenic)
T or F:
Kidd antigens can be denatured with enzyme treatment
F
(instead, enhanced reactivity with Kidd antibodies)
Kidd antigens can be found in platelets, lymphocytes, monocytes, and granulocytes
F
T or F:
Kidd blood group exhibit dosage effect
T
T or F:
Jka is more frequently encountered than Jkb
T
What methods can enhance Kidd antibody detection?
1) LISS or PEG (promote IgG attachment)
2) Using four drops of serum (increases antibody-antigen ratio)
3) Enzyme treatment (ficin or papain)
Can Kidd antibodies bind complement?
Yes, many examples do
Why is serum preferred over plasma for Kidd antibody detection?
Serum allows complement activation, which aids detection.
What type of hemolysis is commonly associated with Kidd antibodies?
Extravascular, but intravascular can occur in severe cases.
Why are Kidd antibodies a common cause of delayed hemolytic transfusion reactions (DHTRs)?
Their titers drop quickly, making them hard to detect.
What antigen is targeted by all Kidd antibodies?
Jk3 (present on Jka+ and Jkb+ RBCs).
Are Kidd antibodies usually IgG or IgM?
Mostly IgG, but can have an IgM component.
On which chromosome is the Jk locus located?
Chromosome 18 (18q11-q12)
What gene encodes the Kidd blood group system?
SLC14A1
What is the function of the SLC14A1 gene?
It encodes a urea transporter
How many exons does the SLC14A1 gene have?
11 exons
What causes the Jka/Jkb polymorphism?
An amino acid substitution at position 280
Where is the Jka/Jkb polymorphism located on the glycoprotein?
On the fourth extracellular loop.
Are Jka and Jkb inherited dominantly or codominantly?
Codominantly.
Which antigens are absent in the Jk(a–b–) phenotype?
Jka, Jkb, and Jk3
Which populations have the highest occurrence of the Jk(a–b–) phenotype?
Polynesians, Filipinos, Indonesians, and Chinese.
Has the Jk(a–b–) phenotype been reported in European populations?
Yes, in Finnish, French, Swiss, and English families.
Which South American indigenous group has reported cases of the Jk(a–b–) phenotype?
Mato Grosso Indians of Brazil.
What screening method is used to detect Jk(a–b–) RBCs?
Delayed lysis in 2M urea.
Are there any clinical abnormalities associated with the Jk(a–b–) phenotype?
may have defect in urine concentration
What do family studies indicate about the inheritance of the Jk(a–b–) phenotype?
It is typically homozygous for the silent Jk allele.
Why do parents of Jk(a–b–) individuals never type as Jk(a+b+)?
Because they inherit JkaJk or JkbJk, leading to a single-dose expression of Jka or Jkb.
What dominant gene is associated with the Jk(a–b–) phenotype?
In(Jk) (inhibitor gene).
T or F:
Individuals with the dominant Jk(a–b–) phenotype produce anti-Jk3.
F
(since they still have some Kidd antigens)
Dominant type vs recessive type Jk(a-b-)
dominant: inheritance of In(Jk) gene
recessive: inheritance of JkJk (silent Jk)
What RBCs does anti-Jk3 react with?
All Jk(a+) or Jk(b+) RBCs except the autocontrol (since anti-Jk3 is an alloantibody)
What type of antibody is anti-Jk3?
IgG, reactive in AHG phase
How can blood banks confirm suspected anti-Jk3?
By antigen typing, since most blood banks lack rare Jk(a–b–) cells.
What enhances the reactivity of anti-Jk3?
Enzyme pretreatment of RBCs (e.g., ficin, papain).
What are two major clinical concerns associated with anti-Jk3?
Severe hemolytic transfusion reactions (HTRs) and mild hemolytic disease of the fetus and newborn (HDFN).
What type of anemia has been associated with Kidd autoantibodies?
Autoimmune hemolytic anemia (AIHA).
T or F:
autoantibodies with Kidd specificity are common
F
(rare)
organisms with Jkb-like specificity
Entereococcus faecium
Micrococcus
Proteus mirabilis
