Antigens/Antibodies Flashcards
What is the linkage for a Type II chain
Beta 1-4
What is the linkage for a Type I chain
Beta 1-3
Alpha Linkage
The hydroxyl group is below the plane
Beta LInkage
The hydroxyl group is above the plane
Blood Group vs a collection
Blood group has known genetic origin a collection does not
Gene and chromosome for I antigen
GCNT2*01 chromosome 6
I blood group ISBT number
027
I enzyme
Branching Enzyme: B-1,6 acetlyglucosaminyltransferase
Antigens that are destroyed by DTT
Lutheran, Dombrock, Cartwright, Indian, Kel
ABO Chromosome
9
ABO ISBT
001
Blood Group A chemical structure
N-acetylgalactosamine
Blood Group B chemical structure
Galactose
FUT1
Chromosome 19, encode for H, Fucosyltransferase adds fucose group onto Type 2 chains on RBCs
FUT2
Chromosome 19, encode for Se, fucosyltransferase adds fucose group onto Type 1 chains in serum/secretions
First autosomal linkage discovered in humans
Lutheran and Se on chromosome 19
Lutheran a-b- options
- autosomal recessive, inheriting two copies of silent gene, true null can make anti-Lua, anti-Lub, anti-Lu3
- autosomal dominant inhibitor. In(Lu), inhibitor prevents expression of lutheran through mutations in EKLF (erythroid kruppel like factor) can’t make antibodies (also suppresses P1, Anwj, In, Knops, Cost, Mer2) trace amounts of Lub detected by adsorption/elution
- x-linked one family in australia, women are mainly unaffected carriers, unless they receive two copies of mutated x, men are affected. Shouldn’t make Lu3 (also known as LuMod) trace amounts of Lub detected by adsorption/elution
H antigen expression quantity by blood group
0> A2>B> A2B> A1> A1B> H deficient
ABO-Histo-Blood group antigens
Found in all organ tissues in the body, platelets and environment including bacteria and animals
Anti-B Lectin
bandeiraea simplifica
Anti-A1 lectin
dolichos bifloris
Anti-H lectin
ulex europeas
Anti-A lectins (3)
dolichos bifloris, phaseolus limensis, helix pomatia
Acquired B
colonic obstruction, colon cancer, sepsis, bacteria carrying deactylases take n-acetyl group off of A antigen, leave only galactosamine, reacts with Anti-B reagent showing both as positive.
Testing to trouble shoot acquired B
- test against patients own plasma, patients plasma won’t react. 2. add acetylanhydramine, will put acetyl group back onto the galactosamine. 3. using a different monoclonal reagent anti-B to see if the same reaction takes place 4. acidifying the reaction mixture of human RBCs and reagent antibody will stop this result if it’s caused by acquired B.
Lewis antigen frequency (all)
Lea-Leb+ (whites 72%) blacks (52%) Lea+Leb+ (very rare, usually in asian populations weak secretor) Lea+Leb- Whites(22%) blacks (19.5%) Lea-Leb- Whites (6%) blacks (28.5%)
FUT3
fucosyl transferase, Lewis antigen gene. Adds fucose group on to Type1 chains. Usually weaker to the secretor gene, if there is no secretor fucose then it is Lea if there is already secretor fucse then it is Leb
Who makes Anti-LeAB
A, B or AB, Lea- Leb- secretors
FORS1 gene
GBGT1
p (null phenotype)
Lackin P1, P and Pk. Rare recessive inheritance, missese and nonsense mutation sin the A4GALT gene, Stronger PX2 expression. High Consanguinity (being descended from the same ancestor) rate -Amish Community
All about P1K and P2K Phenotype
Both very rare in all populations, recessive traits. Mutations in B3GALNT1- absence of P antigen, all Pk individuals have naturally occurring anti-P in their serum react equally with P1K and P2K
Rare RH phenotypes
dcE, DCE, dCE (1% or less) dCe (2%)
Most common White Rh Phenotype and percentage
R1 42%
Most common Black Rh phenotype and percentage
R0 44%
Most common Asian Rh phenotype and percentage
R1 70%
2nd most common White Rh phenotype and percentage
r 37%
2nd most common Black Rh phenotype and percentage
r 26%
2nd most commone Asian Rh phenotype and percentage
R2 21%
Most common white full Rh phenotype
R1r
Two most common black full Rh phenotype
Ror, RoRo
Difference in RhD and RhCe a.a.,
Difference between E/e and C/c
34 to 37 a.a. difference (E)Proline 226 Alanine (e), C (Serine) 103 to Proline (c)
RHD pseudo gene
37 b.p. added in exon 4- inactivates. psi in african americans resulting in inactive gene and an early stop codon placement, present in 24% of D negative A.A. Rh negative patient.
3 D negative options
- Deletion of RHD 2. Pseudogene RHD, Hybrid RHD-CE-D r’s 3. Del
RhAG
Rh Glycoprotein, carry ABO structures, Chromosome 6 RhAG gene 409 a.a. Crosses membrane 12 times, absent on RH null U- red cells. RhAG protein is required for expression of Rh proteins
ICAM-4
This gene encodes LW (Landsteiner-Weiner) Blood Group Gln-100 (LWa) Arg-100 (LWb)
What percent of Rh negative people exposed to D+ will make antibody
50-80% healthy people, 21-22% patients
Ceppellini effect
C in trans with RHD, r’ haplotype, Weak expression of D due to being trans to C. Not at risk of making anti-D
Types of Weak D not at risk of making anti-D
Types 1, 2, 3 (alterations made in intra-membrane region of the protein structure) not exposed differences
Partial D
Lack of or altered exofacial epitopes,
Partial D european
- DNB 2. DVI 3. DVII most common
Partial D African
- DIIIa 2. DAR (Weak D type 4.2) most common
DVI
Fatal Hydrops Fetalis cases. Anti-D reagents are designed to be negative at IS-Pos at IAT
Partial D Hybrid Alleles
- DIIIa
- DIVa
- DVa
- DVI-2,-3,-4
- DVII
- DFR
- DBT
Low prevalence Antigen
- DAK
- Goa
- Dw
- BARC
- Tar
- FPTT
- Rh32
Del
Types as D negative, only absorptions and elutions will detect antigen. Severly reduced protein. Deletion of exon 9 in Asians (10-30%)
Crawford Phenotype
Seen in 1/900 blacks. Patient is D negative, there is an amino acid change in RHCE gene makes antigen appear “D-Like: Gamma clone reagent will react with this and make it look like it’s typing D Pos. Patients can make anti-D. ‘ceCF’ phenotype, 3 nucleotide changes 48G>C , 697C>G 733C>G
ceHAR
D epitope on RHCE gene. Results from one RHD exon (EXON6?)insterted into the RHCE gene. In serological typing, positive with all anti-D reagents EXCEPT the Ortho Bioclone it’s negative.
P chromosome
chromosome 22
Antigen Frequencies, Fors1, NOR, LKE, PX2
FORS (0.1%) NOR- 2 families LKE (98%) PX2 (99%)
Left leg branch of the P system
Lactosylceramide-> Lactotriaosylceramide->Paragloboside (A4GALT) creates P1 and B3GALNT1 creates PX2
Right leg branch of the P system
Lactosylceramide-> (A4GALT) pK-> (B3GALNT1) (GLOB) P globoside (can then be converted to LKE, Nor, FORS1
P1PK system and gene
P1 Pk Nor 003 Alpha4Galt
Globoside system and gene
P, PX2 028 B3GALNT3
FORS system
Fors1
GLOB collection
LKE, 209
P1 frequency
79% Whites, 94% Blacks
P2 frequency
21% Whites 6% Blacks
p, P1K, P2k frequency
rare, very rare, very rare
f antigen, antibody
ce, anti-f (anti-hrs=anti-f like) c negative and e negative individuals do not have f antigen on red cells, either can be given as acceptable antigen negative in presence of antibody
rhi antigen, antibody
Ce, anti-Rhi (anti-hrb=anti-Rhi like)
Rh, Enzymes/DTT?
Enhanced by proteolytic enzymes, unaffected by DTT
RH27
cE
RH22
CE
RH8, RH9
Cw and Cx, not a different form a different epitope. Point mutations in the RHCE gene
Cw mutation and what it is
122 A>G, antithetical to high prevalence antigen MAR, this antigen is separate from C/c, clinically significant antibody very easy to find antigen negative blood for
Cx mutation
106 G>A
MAR
High incidence RH blood group antigen, Finnish population. Anti-Mar nonreactive with Rh null, D–. Antithetical to Cw and Cx
G and anti-G
G antigen 103Serine position in common between D pos and C pos cells. Most C+ or D+ RBCs are G+. Anti-G appears as an anti-D and an anti-C
Adsorption/Elution anti-G identification
First Adsorption r’ (C+G+), second adsorption R0 (D+G+)
Partial e with Anti-e
most often found in african americans. This is typically because of variant e genotype, missing a portion of the epitope
Rh null amorph
absent Rh protein, reduced RhAG, RhCE altered RHD deleted
Rh null regulator
Absent Rh protein, Absent RhAG, RHag mutated/ deleted, Rhnull individuals have no Rh antigens (no Rh or RhAG) on their red blood cells.[44] This rare condition[44] has been called “Golden Blood”.[45] As a consequence of Rh antigen absence, Rhnull red blood cells also lack LW and Fy5 and show weak expression of S, s, and U antigens. Red blood cells lacking Rh/RhAG proteins have structural abnormalities (such as stomatocytosis) and cell membrane defects that can result in hemolytic anemia.[32][44] Only 44 individuals have been reported to have it worldwide.
RH Null, LW presentation
All Rh null are LWa-Lwb-
LW cord cell expression
Strong regardless of Rh status
Rh negative, LW presentation
Lwa and Lwb are weaker on RH negative cells than Rh positive cells
Anti-LW
Shows relative anti-D specificity, same reaction with D- and D+ cord cells*** can be a way to differentiate between LW and D antibody. Doesn’t react at all with Rh null cells
For transfusion D-, LW+ units can be transfused. Non-reactive with DTT treated cells
XK gene
on X chromosome
K gene
on chromosome 7
K antigens
K, k, Jsa, Jsb, Kpa, Kpb, normal expression is k, kpb, jsb. any difference comes with mutations
Kpa frequency
2% Whites, rare in blacks
Jsa frequency
20% in blacks, 0.01 in whites
K frequency
9% in whites, 2% in blacks
Ko frequency
True Kell null, SNP of Kel*02, no Kell glycoproteins, Cells Kx+s, Ku- Km-
Mcleod Phentype
SNP in splice site, protein not formed, no Xk gene, no KX protein no Km, other Kell proteins weak expression, Ku, k, kpb, jsb. Occurs exclusively in males, x-linked. Linked to Chronic Granulomateaus disease
Effect of Gerbich null types on Kell
Yus- Kell normal. Gerbich- Kell expression weakened. Leach- Kell expression depressed
k mod
SNP at Kel*02, weakened expression of kel glycoproteins, strong kx expression (some make anti-Ku-like antibody that reacts with all but Kmod cells)
K group ISBT #
006
Duffy group ISBT#
008
Duffy chromosome
Chromosome 1
DARC
Duffy antigen receptor for chemokines , binds cytokines, especially IL-8, role in inflammation, receptor for malaria, plasmodium vivax, plasmodium knowlesi
Duffy, enzymes
Destroyed by enzymes and ZZAP
Expression of Duffy
Well developed at birth, reported to weaken when stored, antigens found on RBCs and other tissues, lung, brain, kidney etc.
Fy3 Fy5 frequency
100% whites, 32% blacks ( for both)
Fya- Fyb-
0% whites (when seen usually true null) 67% black GATA box mutation promoter region. Fy01 or FY02(MORE COMMON) not expressed on rbcs but still expressed on tissues with GATA mutation
Fya+Fyb- frequency
91% asian, 10% blacks, 20% whites
Fya+ fyb+
48% whites 3% black 9%asian
Fya- Fyb+
32% whites 20% black <1% asian
Anti-Fya vs. Anti-Fyb
20x more common to see Anti-Fya
Anti-Fy3
Found only in Fya-Fyb- (true null) reactivity won’t go away with enzymes, acts like inseparable anti-Fya anti-Fyb
Anti-Fy5
Found only in Fya-Fyb- individuals, reacts with all cells except fya-fyb-. Rh null cells regardless of their fya/fyb typing. D– have weakedned Fy5 expression
Anti-Fy6
Murine antibody not found in humans
Enzymes Duffy antibodies
Fy3 and Fy5 are restistant all other antibodies of Duffy destroyed
Kidd blood group ISBT
009
Jk01 and Jk02 chromosome
Chromosome 18
Another name of JK
HUT 11 Human Urea Transporter 11, uptake of ureaa, prevents RBC shrinkage in hypertonic environment of renal medulla
Jk3 antigen
absent/weak in JKa-b- individuals
Jk null
True null (homozygous for Jka gene, no jka, jkb or jk3- polynesians or finns) Dominant inhibitor In(Jk) -reported in japanese families no jka no jkb, weak jk3 expression (antigens may be detected by adsorption/elution cannot make antibodies)
Jk antigens on surface
Cluster on surface- more likely to activate complement due to close proximity
Jk enzymes, DTT
not destroyed by DTT, enhanced by enzymes
Jka+b- frequency
26%whites 52%blacks
jka+jkb+
50%whites 40% blacks
jka-jkb+
24%whites 8%blacks
2M Urea Lysis Test
cheap effective way to identify Jka-Jkb- individuals, Cells with normal Kidd antigen will swell and lyse due to HUT11, JKa-Jkb- cells resis lysis by 2M urea but will shrink and shrivel
Can Jk antibodies activate complement
yes- clustered on the surface of the red cell
Anti-Jk3
looks like inseparable anti-Jka and anti-Jkb. Confirm with adsorption/elution studies, can only be made by true Jk null
MNSs Isbt number
002
Glycophorin A translates for
M and N and Ena
Glycophorin B translates for
S and s and U
Mur+
From GYPA antigen more common in SE asia, normally low prevalence but up to 90% in Taiwan. Hybrid M/N antigen, significant antibodies can form
What Differentiates s from S
snp at AA 48 defferentiates S(Met48) from s(48Thr)
Is there more GPA or GPB on RBCS
GPA. 10^6 copies per cell compared to around 200,000 GPB
What aids in negative charge of red cells
MNS glycophorins rich in sialic acid with negative charge
Difference in M and N
M a.a.1-Serine a.a.5-Glycine. N aa1-Leucine a.a.5-Glutamic acid
MNS- enzymes
M, N S, s destroyed by enzymes, U is resistant Ena is variable. EnaTS- Typsin sensitive, EnaFS-ficin sensitive, EnaFR- Ficin Resistant
Lacking GPA
M-N- Ena- Wra- Wrb-. GPA closely associated with Band3 and Diego system. GPA is required for expression of wright b.
Mg
in GPA lacking individuals- low resulting from gene rearrangement