Major Blood Group Systems Flashcards
What is the frequency of the D antigen in Blacks and Whites respectively?
92% and 85%
What are the antigen frequencies of the C and little c antigens in blacks and whites respectively?
blacks: only 34% big C, but 97% have little c
whites: 70% have big C!, and 80% have little c (compare to blacks! lower)
How common is big E in blacks and in whites respectively?
B: only 21% W: only 30%
which is why you will see more antibodies against big E
How common is little e in blacks and whites?
very common in both, 99 % and 98 % respectively
what is the G antigen? where is it present?
an antigen present on most D positive but ALL big C positive RBCs; In antibody id testing anti-G acts like \anti-D plus anti-C. For transfusion not necessary to discriminate bc pt will receive C-D- blood
what is the f antigen?
expressed when both little c and little e are on the same haplotype; only DCE/dce shows positive reactivity
is the f antigen clinically significant?
has caused HDFN and transfusion reactions, so give either c or e negative blood bc will automatically be f negative
IN what group are the V and VS antigens more prevalent?
African Americans
Do common blood bank enzymes enhance or decrease Rh antigen reactivity? Are they saline or AHG reactive?
enhances; sometimes saline but mainly AHG
warm-autoantibodies often appear to have what Rh antigen specificity?
little e
what are the antigen frequencies of K and k in blacks and whites?
K: rare in blacks, ~9% in whites
little k: 100% in blacks, 98.8% in whites
which Kell antigens are high frequency?
little k, Kp^b, Js^b, Kx.
how do common enzymes in blood bank affect Kell antigens? what about ZZAP, AET?
common enzymes have no effect; AET and ZZAP decrease reactivity
how do enzymes such as ficin and papain modify the RBC surface?
they remove sialic acid residues and denature or remove glycoproteins
what is ZZAP and what does it remove or modify?
combo of papain and dithiothreitol; removes antibodies, complement, Kell, M and N, and Duffy a and b. ZZAP used mostly in reference lab warm-auto workups
what is DTT ? what other reagents are similar?
dithiothreitol, a sulfhydryl reagent that dissolves disulfide bonds between cysteine amino acids; AET (2-aminoethylisothiouronium bromide ) and 2-ME (2-mercaptoethanol)
when is DTT useful?
it eliminates IgM but mostly leaves IgG; can eliminate Kell, and can eliminate panagglutination caused by the anti-CD38 monoclonal therapy daratumumab (called DARA) but must give K- blood since can’t test for it afterwards
what are the frequencies of Duffy a and b in blacks and whites?
Duffy a: 65% in whites and only 10% in blacks!
Duffy b: 80% in whites and only 23% in blacks
frequencies of the KIdd antigens in whites and blacks
Jka: 77% in whites, 91% in blacks
Jkb: 73% in whites, only 43% in blacks
compare enzyme treatment effects on Duffy vs Kidd antibody reactivity
Duffy: destroyed
Kidd: enhanced!!!
which antibodies are notorious for causing DHTRs and why
Kidd; they go low-titer quickly, becoming undetectable, but will build up again if patient exposed
