MIDTERM LECTURE 2: UNCOMMON BLOOD GROUPS Flashcards
How many antigens are in the Diego system?
22 antigens, including three sets of high and low antithetical pairs (Dia/Dib, Wra/Wrb, and Wu/DISK) and 16 low-prevalence antigens.
What is the ISBT designation and system number for Diego?
DI
#010
How did the Diego system get its name?
It was named after a Venezuelan family in which the first antibody was identified during an HDFN investigation.
Where is the SLC4A1 gene located?
On chromosome 17 (17q21.31).
What was the first reported Diego antibody, and when was it discovered?
Anti-Dia, reported in 1955 after causing HDFN in a Venezuelan baby.
How common is the Dia antigen?
Rare in most populations but polymorphic in Mongoloid ancestry. Its prevalence can be as high as 54% in South American Indians.
What is the prevalence of the Dib antigen?
Generally >99%, but 96% in Native Americans.
What phenotype has not been reported in the Diego system.
Di(a–b–).
Wrb requires band 3 interaction with normal glycophorin A (GPA) from which blood group for expression
MNS
phenotype of GPA-deficient RBCs
Wr(a-b-)
Which low-prevalence Diego antigen is sensitive to papain?
Bpa
T or F:
Diego antigens are expressed on RBCs of newborns
T
antibody class of Diego antibodies
usually IgG, reactive in AHG phase; sometimes IgM
Which Diego system antibodies are associated with HDFN and hemolytic transfusion reactions (HTRs)?
Anti-Dia, anti-Dib, and anti-Wra.
What condition is autoanti-Wrb associated with?
Warm autoimmune hemolytic anemia (AIHA).
Which low-prevalence Diego antigen antibody has caused severe HDFN?
anti-ELO
How many antigens make up the Yt system?
Two antigens: Yta (high-prevalence) and Ytb (low-prevalence).
How did the Yt system get its name?
Named in 1956 after the first antibody maker, whose last name was Cartwright. The system name came from the last letter “t” in Cartwright, and “why T” was shortened to Yt.
What is the ISBT designation and system number for Yt?
YT (011).
What is the prevalence of Yta and Ytb in different populations?
Yta is a high-prevalence antigen in all populations.
Ytb is found in about 8% of whites and 21%-26% of Israelis but is not found in Japanese.
What are the observed phenotypes in the Yt system?
Yt(a+b–) → Common
Yt(a+b+) → Common
Yt(a–b+) → Rare
Yt(a–b–) → Not reported
What are Yt antigens based on?
An amino acid substitution on acetylcholinesterase (AChE)
What is the function of RBC-bound acetylcholinesterase (AChE)?
Unknown, but AChE plays a key role in neurotransmission.
Where is the ACHE gene located?
On chromosome 7 (7q22.4).