Other Blood Group 1212
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Transcript of Other Blood Group 1212
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Other Blood Group systemsM kasthuri bai
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Basic terms to remember
C linical significance : antibodies that areassociated with decreased R BC survival
Transfusion reactions HDN
Not clinically significant : antibodies that do notcause red cell destruction
C old reacting antibodies : agglutination bestobserved at or below room temp.Warm reacting antibodies : agglutination bestobserved at 37 C
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Other antigens
LewisIi
PMNSsKell
KiddDuffy
Lutheran
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Systems that Produce C old-Reacting Antibodies
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Lewis AntigensSoluble antigens produced by tissues andfound in body fluids (plasma)Adsorbed on the R BC
Legenes
Le substancein plasma
RBC
Lewis substanceadheres to RBC
becoming an antigen
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Lewis inheritanceLewis system depends on Hh , Se, and Le genesle, h , and se do not produce products
If the Le gene is inherited , Lea
substance is producedLe, H , and Se genes must ALL be inherited toconvert Le a to Le b. Examples:
Le , se , H Le(a+b-) Le , Se , H Le(a-b+) le , H se Le(a-b-) le hh se Le(a-b-)
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Lewis AntibodiesUsually occur naturally in those who are Le(a-b-)
IgM
May be detected soon after pregnancy because
pregnant women may temporarily becomeLe(a-b-)
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I antigensThese antigens may be I or iThey form on the precursor chain of R BC
Newborns have i antigenAdults have I antigen
i antigen (linear) converts to I (branched) asthe child matures (precursor chain is morelinear at birth) at about 18 months
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I antibodiesMost people have autoanti-I (RT or 4 C)
Alloanti-I is very rare
Cold-reacting (RT or below ) IgM antibody
Clinically insignificant
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P AntigenSimilar to the A BO system
The most common phenotypes are P1 and P2 P1 consists of P1 and P antigens P2 consists of only P antigens
75% of adults have P1
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P1 AntigenStrength of the antigen decreases uponstorageFound in secretions like plasma andhydatid cyst fluid C yst of a dog tapeworm
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P antibodiesAnti-P1 Naturally occurring IgM
Not clinically significant C old agglutinin
Anti-P Naturally occuring IgM Wide thermal range
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MNSs B lood SystemStrucrural protein of red cells4 important antigens (more exist): M N S s
M & N located on Glycophorin A
S & s and U located on GlycophorinB
Remember: Glycophorin is a protein that carriesmany R BC antigens
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MNSs Antigens
RBC
Glycophorin A
Glycophorin B
M
N
SsU
M & N only differ in
their amino acidsequence at positions1 and 5
S & s only differ intheir amino acid
sequence at position29
.5, 4, 3, 2, 1 (NH 2 end)COOH end ..
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MNSs antigensall show dosage
M & N give a stronger reaction whenhomozygous , (M+N-) or (M-N+)Weaker reactions occur when in the
heterozygous state (M+N+)
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Anti-M ,-N ,-S ,-s antibodiesAnti-M and anti-N IgM (rarely IgG)
C linically insignificant
Anti-S, and Anti-s C linically significant IgG C an cause R BC destruction and HDN Anti-s reacts at thermal but Anti-S at cold
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MNSs AntibodyC
haracteristicsAntibody IgG C lass C linicallysignificant
Anti-M IgM (rare IgG) No
Anti-N IgM No
Anti-S IgG Yes
Anti-s IgG Yes
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Systems that Produce Warm-Reacting Antibodies
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K ell SystemMembrane bound enzyme
2 major antigens (over 20 exist) K (K ell) , 90% of population
The K and k genes are codominant alleles on
chromosome 7 that code for the antigens
The K antigen is very immunogenic ( 2nd to the Dantigen) in stimulating antibody production
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K ell antibodies
IgG (react well at AHG)Produced as a result of immune stimulation(transfusion , pregnancy)C linically significantAnti-K is most common because the K antigen is extremely immunogenic
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K idd Antigens
Membrane transporters or channelsWell developed at birthNot very accessible on the R BC membrane
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K idd antibodies
Anti-Jk a and Anti-Jk b
IgG C linically significant Implicated in HTR and HDN C ommon cause of delayed HTR
Usually appears with other antibodies whendetected
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Duffy B lood GroupC hemokine receptors
Predominant genes (codominant alleles): F ya and F yb code for antigens that are well
developed at birth
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Duffy antibodiesIgG
C linically significantStimulated by transfusion or pregnancy (butnot a common cause of HDN)
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The Duffy and MalariaC onnection
Most African-Americans are Fy(a-b-)Interestingly , certain malarial parasites
( P la sm odiu m kn owle s i and P. v ivax ) will notinvade Fy a and Fy b negative cellsIt seems either Fy a or Fy b are needed for themerozoite to attach to the red cell
The Fy(a-b-) phenotype is found frequently inWest and C entral Africans , supporting the theoryof selective evolution
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LutheranB
lood Group SystemC ell adhesion molecules2 codominant alleles: Lua and Lub
Weakly expressed on cord blood cellsMost individuals (9 2%) have the Lu b
antigen , Lu(a-b+)The Lu(a-b-) phenotype is RARE
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Lutheran antibodiesAnti-Lu a IgM and IgG Not clinically significant
Reacts at room temperature Mild HDN Naturally occurring or immune stimulated
Anti-Lu b
Rare because Lu b
is high incidence antigen IgG Associated with transfusion reactions (rare HDN)
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Thank you