Other Blood Groups Flashcards
What is the structure of CO antigens?
Multipass - pass membrane 7x
located on aquaporin-1 (AQP1)
Also called CHIP-28 channel forming integral protein
It is a water channel that is responsible for 80% of the water that is reabsorbed in the kidneys
What antigens are present in Colton (CO) BGS?
Coa and Cob are co dominant (Coa = High)
Co3 and Co4 are high freq. present when colton antigens are present >0.01% is Co(a-b-)
What are characteristics of the Colton antigens?
Present on cord cells = mild/severe HDFN
Not destroyed by DTT or enzymes
Poor immunogens - few Colton antibodies seen
Weak typing seen in In(Lu) phenotype
What is Co null?
Co(a-b-) Caused by silencing of CO gene Cells are Co:(-a,-b,-4,-5) Co-3 = no aquaporin and may have serious electrolyte and metabolic disorder when dehydrated Co-4 = have functional aquaporin
What are the characteristics of Co antibodies?
IgG; reacts are IAT Have been implicated in HTR and HDFN May bind complement Cob - found w/ other antibodies (XM comp; 8% Cob+) Coa require rare antigen neg units
How do you antigen type for Coa?
No antisera available.
Molecular typing can be preformed
What chromosome is Xg located on?
Chromosome X
Xga and CD99 escape x inactivation
What antigens are present in Xg BGS?
Xg1 = Xga on RBC’s
Xg2 = CD99 a high prevelance antigen that is also present on fibroblast and lymph nodes
Phenotype is either Xga- or Xga+
How is Xga inhierted?
Xga is X linked dominate - occurs in females more often
Males will be hemizygous if inherit from mother and will pass Xga to all daughters
What % of females and males are Xga positive?
66% of males are Xga positive
90% of females are Xga positive
What are the characteristics of Xga antigen
Sensitive to enzymes
Resistant to DTT
Poor immunogen
What are the characteristics of anti-Xga?
IgG reacts at IAT
immune stimulated
May see MF due to low density of antigens on the RBC’s
What is lyonization?
In females, a random X chromosome is inactivated early in somatic cell developement.
Once a x chromosome is inactivated all cells from that clonal will have the same X inactivation
Xga escapes lyonization= no dual population of RBC
What is the gene name for Diego BGS?
DI or SCL4A1
What is the gene product for DI?
Band 3 (anion exchanger 1)
What is structure/function of Diego antigens?
Diego is a multipass glycoprotein on band 3
Makes up 20% of membrane protein
Band 3 transports anions of bicarb and Chloride across the cell membrane and allow CO2 to enter
Band 3 is achnored the membrane by ankyrin and protein 4.2
What disease is associated with lack of band 3?
Mutation in band 3 results in SE Asian ovalucyctosis, hereditary spheocyctosis, and some acantocytosis
What are the High frequency DI antigens?
Dib, Wrb, and DISK
Di(a-b+) = most common
What are the characteristics of Dia antigens?
Present on Cord cells
Can cause HDFN
Resistant to Ficin and DTT
What is frequency of Dia?
Very low freq. in Caucasians
Present in Mongolian populations
50% of S American Indians
12% of Asians
What are the characteristics of DI antibodies?
IgG1 and IgG3
Can cause HDFN
Immune stimulated (one naturally occur. anti-Dia)
What is prevelance of Wra and Wrb antigens?
Wra is low frequency
Wrb is 100% frequency
Where is Wrb antigen located on?
It is on AE-1 in close association with GPA
GPA is required for Wrb expression
GPA neg and MkMk individuals lack Wrb
What are the characteristics of Wra antibodies?
IgG and IgM
Can be naturally occur. Found in 2% of un-transfused males and seen in pregnant women
Often seen with other antibodies or warm auto’s
Relatively common
Can cause HTR and HDFN
What are the characteristics of Wrb antibodies?
Allo anti-Wrb is rare
Made by Ena- M-N- individuals
Auto anti-Wrb can occur and cause hemolysis
What is the former name of the YT BGS?
Cartwright
it is YT and not Yt
What is the gene name and chromosome location of YT?
Located on Chromosome 7
Gene name is YT or ACHE
What is the structure of YT antigens?
On a glycophosphatidylinositol (GPI) linked glycoprotein acetylcholinesterase
What is the function of AChE?
AChE plays an essential part in neurotransmission.
What diseases are associated with AChE?
RBC’s from PNH III are deficient in AChE
AChE is reduced in MDS and some SLE
What antigens are in the YT BGS?
Yta and Ytb
Yta is high frequency (0.3% negative)
8% are Ytb positive
NO Yt(a-b-) found to date
What antigens are linked to the RBC membrane by aglycophosphatidylinositol (GPI) linked glycoprotein?
YT Dombrock Cromer JMH EMM
Can anti-Yta or Ytb cause HDFN?
Yta is not developed at birth. It is weak or negative on cord cells so doesn’t cause HDFN.
Ytb is present at birth
Are YT antigens sensitive to enzymes or DTT?
Yta and Ytb are sensitive to ficin and DTT but resistant to trypsin
What are the characteristics of anti-Yta?
IgG1 and IgG4
MOSTLY BENIGN, but some cause HTR
If anti-Yta is IgG4 it will not cause hemolysis because macrophages do not have receptors for IgG4
Weak reactive antibody destroyed by enzymes and weakend with DTT
How can you determine if patients anti-Yta is clinically significant?
Monocyte monolayer assay CR51 survival - invassive procedure IgG subclass assay consider giving Yta positive blood in an emergency 50% are not clinically significant
What are the characteristics of anti-Ytb?
IgG
Rare antibody, reported in patients who had multiple transfusions (Ytb is low present in 8% individuals)
Not considered clinically significant or known to cause HTR/HDFN.
What is the gene name and gene product for scianna?
SC is gene name
Product is Sc glycoprotein ERMAP (erythroid membrane associated glycoprotein)
What antigens are present in the SC BGS?
7 antigens that are high freq except SC2 and SC4
SC3 is present when either Sc1 or Sc2 is present
SC4 = Radin
SC5 = STAR
SC6 = SCER
SC7= SCAN
Are the SC antigens resistant to enzymes or DTT?
SC antigens are resistant to enzymes and varied with DTT
What is the frequency of Sc1,-2?
99%
What is the frequency of SC-1,2?
Very rare
What is the frequency of SC-1,-2,-3 (Null)
Very rare
Cluster of people found in Papa New Guinea
- can make anti-SC3 that reacts with all SC1 or SC2 positive cells
What are the characteristics of SC antibodies?
SC antibodies are rare
IgG but generally don’t cause HTR or HDFN
Anti-SC2 and SC4 may cause mild HDFN
Anti-SC3 made by Sc null may cause HTR
What is the gene name and gene product for Dombrock BGS?
Gene is DO
Gene product is Dombrock glycoprotein
What is the structure of Dombrock
glycophosphatidylinositol (GPI) linked glycoprotein
What is the disease associated with Dombrock?
Dombrock is absent from PNH III cells
What are the Dombrock high frequency antigen?
DO3 = Gya DO4 = Hy DO5 = Joa DO6 = DOYA DO7 = DOMR DO8 = DOLG
What are the frequencies of Doa and Dob antigens in whites?
Doa = 67% are positive
Dob = 82% are positive
(similar to Fya/Fyb)
What is the Gya negative phenotype?
True DO null NO Dombrock antigens Extremely rare Found in eastern Europeans and Japanese Anti-Gya found in whites
What is the Hy negative phenotype?
Anti-Hy Found in blacks
Weak Dob and Gya.
Negative Doa, Hy, and Joa
What is the Joa negative phenotype?
Unusual; Anti-Joa found in blacks
Negative Joa
Weak Doa, Weak/neg Dob, Weak Hy, and Weak Gya
What are the characteristcs of DO antigens?
Resistant to ficin and papain
Destroyed by DTT and trypsin
DOa and Dob developed at birth
Poor immunogen