TM 4 (Blood groups) Flashcards
Increased by enzymes
ABO (Lewis, I/i, P)
Rh
Kidd
Decreased by enzymes
MNS, Duffy
Room-temp, usually clinically insignificant Abs
M, N, Lewis, I, P
Alloantibody notorious for becoming undetectable
Kidd
Dosage
Kidd, Duffy, Rh, MNS
Carbohydrate antigens
ABO, Lewis, I, M, N, P
Location of A & B genes
Ch9
Type 1 H-antigen chains present where
Secretions
Type 2 H-antigen chains present where
RBC membranes
Se gene
FUT2 enzyme adds fucose to type 1 chains
Makes Type 1 H-antigen in secretions
80% gene frequency
H gene
FUT1 enzyme adds fucose to type 2 chains
Makes Type 2 H-antigen on RBCs
~100% gene frequency
Group A sugar
N-acetylgalactosamine on terminal galactose
Group B sugar
Galactose on terminal galactose
Relative amounts of H by blood group
O>A2>B>A2B>A1>A1B
Group A2
less A than A1
may make anti-A1
What agglutinates A1 but not A2
Dolichos biflorus
ABO frequencies in Caucasians
O-45%
A-40%
B-10%
AB-5%
ABO frequencies in AAs
O-50%
A-25%
B-20%
AB-5%
Neutralized by guinea pig urine
Sda
Neutralized by Hydatid cyst fluid
P1
Neutralized by saliva
H
LeA
Neutralized by breast milk
I
Neutralized by pigeon egg fluid
P1
Neutralized by plasma
Chido
Rogers
Acquired B phenotype
Type A person with enteric Gi rods
forward type is discrepant with weak (1-2+) reaction to anti-B sera
the bacteria deacetylate GalNAc to galactosamine (which looks similar to galactose)
Bombay phenotype
no Se or H gene (hh,sese)
strong anti-H, all are type O
Parabombay phenotype
have Se gene, but not H
Serum/secretion testing shows free H
have anti-H in serum
Lewis blood group has Type ___ chains
Type 1 (floating in plasma)
How is Lewis A made
Le gene (FUT3) adds fucose to subterminal GalNAc = LeA
How is Lewis B made
in secretors, FUT 2 adds fucose to LeA to make LeB
Person with Se gene and Le gene is
Lewis B
Lewis antigens are/aren’t tightly bound to RBCs
Are NOT
% of blacks vs white who are Lewis negative
22% AA
6% Caucasians
Lewis Ags during pregnancy
decrease, may look Le(a-, b-) and make Abs
H. pylori attaches via
LeB
Le(a-b-) children have increased risk of
UTI
Auto-anti-i
EBV
Auto-anti-I
Mycoplasma pneumoniae
cold-agglutinin dz
anti-P,P1,Pk assd with
HDFN
spontaneous abortions
P Ag is _____ receptor
Parvovirus B19
Titers of anti-P1 increase in
Echinococcus infxn
Bird handlers
PCH
anti-P
Donath-Landsteiner biphasic hemolysin, IgG
Assd with syphilis and viral infxn in children
Weiner haplotypes
R1 DCe r’ dCe
R2 DcE r” dcE
R0 Dce r dce
Rz DCE ry dCE
order of haplotypes in caucasians
R1 > r > R2 > R0
order of haplotypes in AAs
R0 > r > R1 > R2
Most common haplotype in AAs
R0 (Dce)
Most common haplotype in caucasians
R1 (DCe)
up to __% of D- will make anti-D to 1 unit RBCs
80%
Weak D =
red cells get coated but not agglutinated by anti-D
do IAT
Partial D
lacks portions of D-antigen
