ABO GROUP PPT 1 Flashcards
most important of all blood groups in both transfusion and transplant medicine
ABO SYSTEM
It is the only blood group system in which individuals already have antibodies in their serum to antigens that are absent from RBCs without any prior exposure to RBCs through transfusion or pregnancy
ABO SYSTEM
(ABO SYSTEM)
Testing to detect ABO incompatibility between a ______ and __________ is the foundation on which all other pretransfusion testing is based.
donor ; potential transfusion recipient
first performed forward and reverse grouping
Karl Lansteiner
In 1901, He was inadvertently the first individual to perform forward and reverse grouping
Karl Lansteiner
_________ is defined as using known sources of commercial antisera (anti-A, anti-B) to detect antigens on an individual’s RBCs.
Forward grouping (front type)
________ is defined as detecting ABO antibodies in the patient’s serum by using known reagent RBCs, namely A1 and B cells.
Reverse grouping (back type)
______ are widespread in the environment, which constantly exposes individuals to A-like and B-like antigens. This exposure serves as a source of stimulation of anti-A and anti-B. All other defined blood group systems do not regularly have “____________” antibodies expected in their serum to antigens they lack on their RBCs.
Bacteria ; naturally occurring
ABO FORWARD GROUPING:
PATIENT RBCS WITH ANTI-A
1. 0
2. 4+
3. 0
4. 4+
PATIENT RBCS WITH ANTI-B
1. 0
2. 0
3. 4+
4. 4+
INTEPRETATION OF BLOOD GROUP???
- O
- A
- B
- AB
ABO REVERSE GROUPING
PATIENT SERUM WITH REAGENT A1 CELLS:
1. 4+
2. 0
3. 3+
4. 0
PATIENT SERUM WITH REAGENT B CELLS:
1. 4+
2. 3+
3. 0
4. 0
INTERPRETATION OF BLOOD GROUP???
- O
- A
- B
- AB
A FORWARD GROUPING REAGENT (CHARACTERISTICS):
- monoclonal antibody
- highly specific
- IgM
- Clear blue-colored reagent
- Expected 3+ to 4+ reaction
- Usually use 1 to 2 drops
Anti A Reagent
A FORWARD GROUPING REAGENT (CHARACTERISTICS):
- monoclonal antibody
- highly specific
- IgM
- Clear yellow-colored reagent
- Expected 3+ to 4+ reaction
- Usually use 1 to 2 drops
Anti B Reagent
A REVERSE GROUPING REAGENT (CHARACTERISTICS):
- Human source
- 4% to 5% RBC suspension
- Expected 2+ to 4+ reaction usually use 1 drop
Reagent A1 and B Cells
(FREQUENCY OF ABO GROUPING)
______ is found twice as frequently in blacks and Asians as in whites.
group B
(FREQUENCY OF ABO GROUPING)
There is also a significant decrease in _____ distribution in these two ethnic populations compared to whites.
group A
(FREQUENCY OF ABO GROUPING)
It has been reported that ______ is rarely found in Asians.
subgroup A2
Individuals normally produce antibodies directed against the ____ or ______ absent from their RBCs.
A and/or B antigen(s)
ABO antibodies are predominantly ______, activate ________, and react at _____ or _______.
IgM, complement, room temperature or colder
ABO Antibodies also, produce strong __________ reactions during ABO testing
direct agglutination
(ABO ANTIBODIES)
PRODUCTION: initiated at birth, but titers are generally too low for detection until infants are ___ to ____ months old
- before 3 to 6 months of age cannot be considered valid because some or all of the antibodies present may be _____ antibodies that crossed the placenta.
- Perform only ______ on the cord blood from newborn infants
3 to 6
- IgG maternal
- forward grouping
Antibody production peaks between ___ and ____ years of age and declines later in life
5 and 10
Elderly people usually have lower levels of _____ and _____
- antibodies may be undetectable in the _____
anti-A and anti-B
- reverse grouping
ABO antibodies can cause ________ if the wrong ABO group is transfused, potentially resulting in patient death.
rapid intravascular hemolysis
Serum from group O individuals contains _______, ______, and ______
- Anti-A,B reacts with both ____ and _____
- cannot be separated into a pure specificity when adsorbed with either A or B cells
- Anti-A,B antibody is not a combination of anti-A and anti-B but is a separate “________” antibody
- usually ____ in nature
anti-A, anti-B, and anti-A,B.
- A and B cells
- cross-reacting
- IgG
The amount of IgG anti-A, anti-B, or anti-A,B in a woman’s serum sometimes allows prediction or diagnosis of ______________ caused by ABO incompatibility
hemolytic disease of the fetus and newborn (HDFN)
Anti-A,B reagent is routinely used for performing ________ of group O donor units
- not required for routine patient ______.
ABO confirmation
- ABO testing
The production and use of ___________ is much more sensitive, to the point where weak A and B antigens are detected routinely.
monoclonal antisera
________ can be prepared using blended monoclonal anti-A and anti-B; polyclonal human anti-A,B; or a blend of monoclonal anti-A, anti-B, and anti-A,B
Reagent anti-A,B
(INHERITANCE OF ABO BLOOD GROUPS)
1924: first described by ______
Berstein
- indicating that an individual inherits one ______ from each parent
- two genes determine which ABO antigens are present on the _______
ABO gene ; RBC membrane
inheritance of ABO genes follows simple __________
Mendelian genetics
One position, or locus, on each __________ is occupied by an A, B, or O gene.
chromosome 9
The O gene is considered an ______,
- no detectable _______ is produced
amorph ; antigen
The __________ is an autosomal recessive trait with the inheritance of two nonfunctional O genes
group O phenotype
(FORMATION OF A, B, AND H RBC ANTIGENS)
Results from the interaction of genes at three separate loci (____, _____, and ___) code for the produce specific __________ that add sugars to a basic precursor substance
ABO, Hh, and Se ; glycosyltransferases
(FORMATION OF A, B, AND H RBC ANTIGENS)
_______ or _______ is the same basic precursor material from which A, B, and H antigens
Paragloboside or glycan
(FORMATION OF A, B, AND H RBC ANTIGENS)
When the terminal galactose on the precursor substance is attached to the N-acetylglucosamine in a beta 1 → 4 linkage, the precursor substance on erythrocytes is referred to as ______
type 2.
(FORMATION OF A, B, AND H RBC ANTIGENS)
______ on the RBC are constructed on oligosaccharide chains of a ________ substance.
ABH antigens ; type 2 precursor
(FORMATION OF A, B, AND H RBC ANTIGENS)
Type 1 precursor substance refers to a beta 1 → 3 linkage between _______ and ________
galactose and N-acetylglucosamine
(FORMATION OF A, B, AND H RBC ANTIGENS)
_______ is the precursor structure on which A and B antigens are made
H antigen
(FORMATION OF A, B, AND H RBC ANTIGENS)
Inheritance of the _____ results in formation of the H antigen
H gene
(FORMATION OF A, B, AND H RBC ANTIGENS)
FUT 1 (H) and FUT 2 (Se) genes are located on chromosome ___, in contrast to the ABO genes located on chromosome ___.
- __ gene inherited to form ABO antigens on the RBCs
- ___ gene inherited to form ABO antigens in secretions.
19 ; 9 ; H ; Se
(FORMATION OF A, B, AND H RBC ANTIGENS)
_______ develop early in fetal life and do not increase much in strength during the gestational period.
ABH antigens
(FORMATION OF A, B, AND H RBC ANTIGENS)
Reactions of newborn RBCs with ABO reagent antisera are frequently _______ than reactions with adult cells.
weaker
(FORMATION OF A, B, AND H RBC ANTIGENS)
RBCs of the newborn have been estimated to carry ________ of the number of antigenic sites
25% to 50%
(FORMATION OF A, B, AND H RBC ANTIGENS)
The expression of A and B antigens on the RBCs is developed by __ to ___ yrs of age and remains constant throughout life.
2 to 4 years
(INTERACTION OF Hh AND ABO GENES)
_______ inherit at least one FUT 1(H) gene (genotype HH or Hh) and two O genes.
Blood group O
(INTERACTION OF Hh AND ABO GENES)
H gene elicits the production of an enzyme called ___________
transfers the sugar L-fucose to an oligosaccharide chain on the terminal galactose of type 2 chains.
α-2-Lfucosyltransferase
(INTERACTION OF Hh AND ABO GENES)
___________: Sugars occupying the terminal positions of this precursor chain and conferring blood group specificity
- ______ is the sugar responsible for H specificity
must be formed for the other sugars to be attached in response to an inherited A and/or B gene.
Immunodominant sugars ; L-fucose
(INTERACTION OF Hh AND ABO GENES)
_____ does not elicit the production of a catalytically active polypeptide transferase
O gene
(INTERACTION OF Hh AND ABO GENES)
_______ has the highest concentration of H antigen.
O blood group
(INTERACTION OF Hh AND ABO GENES)
The ____ gene is present in more than 99.99% of the random population.
- __, is quite rare
- genotype __ is extremely rare.
H ; h ; hh
(Glycosyltransferases and Immunodominant Sugars Responsible for H, A, and B Antigen Specificities)
Gene: H (FUT1)
Glycosyltransferase: ??
Immunodominant Sugar: ??
Antigen: H
Gene: H (FUT1)
Glycosyltransferase: a-2-L-fucosyltransferase
Immunodominant Sugar: L-fucose
Antigen: H
(Glycosyltransferases and Immunodominant Sugars Responsible for H, A, and B Antigen Specificities)
Gene: A
Glycosyltransferase: ??
Immunodominant Sugar: ??
Antigen: A
Gene: A
Glycosyltransferase: a-3-N-acetylgalactosaminyltransferase
Immunodominant Sugar: N-acetyl-D-galactosamine
Antigen: A
(Glycosyltransferases and Immunodominant Sugars Responsible for H, A, and B Antigen Specificities)
Gene: B
Glycosyltransferase: ??
Immunodominant Sugar: ??
Antigen: B
Gene: B
Glycosyltransferase: a-3-D-galactosyltransferase
Immunodominant Sugar: D-galactose
Antigen: B
(INTERACTION OF Hh AND ABO GENES)
_______ refer to the phenotype that lacks normal expression of the ABH antigens because of the inheritance of the _______.
- _________ does not elicit production of α-2- L-fucosyltransferase.
- L-fucose is not added to the type 2 chain and H substance is not expressed on the RBC.
Bombay ; hh genotype
(INTERACTION OF Hh AND ABO GENES)
Blood group A: the ____ (AA or AO) codes for production of α-3-N-acetylgalactosaminyltransferase
- which transfers an _________ sugar to the H substance.
- This sugar confers A specificity
A gene ; N-acetyl-D-galactosamine(GalNAc)
(INTERACTION OF Hh AND ABO GENES)
__________ is linked to a type 2 precursor substance that now contains H substance through the action of the H gene.
A-specific immunodominant sugar
(INTERACTION OF Hh AND ABO GENES)
The A gene tends to elicit _____ concentrations of transferase than the B gene, leading to conversion of nearly all of the H antigen on the RBCs to A antigen sites.
higher
(INTERACTION OF Hh AND ABO GENES)
Blood group B: inherit a B gene (BB or BO)
- codes for the production of _______ and attaches ________ sugar to the H substance
- This sugar is responsible for B specificity
α-3-D-galactosyltransferase ; D-galactose (Gal)
(INTERACTION OF Hh AND ABO GENES)
________ exist on a B adult RBC in response to the conversion of the H antigen by the α-3- D-galactosyltransferase produced by the B gene
B antigen sites
(INTERACTION OF Hh AND ABO GENES)
When both __ and ___ genes are inherited, the B enzyme (α-3-D-galactosyltransferase) seems to compete more efficiently for the H substance than the A enzyme (α-3- N-acetylgalactosaminyltransferase)
A and B
(FORMATION OF A, B, AND H SOLUBLE ANTIGENS)
________: integral parts of the membranes of RBCs, endothelial cells, platelets, lymphocytes, and epithelial cells.
ABH antigens
(FORMATION OF A, B, AND H SOLUBLE ANTIGENS)
______ can also be found in all body secretions.
Their presence is dependent on the inheritance of genes called ______ that regulate their formation.
ABH-soluble antigens ; Sese (secretor genes)
(FORMATION OF A, B, AND H SOLUBLE ANTIGENS)
80% of the random U.S. population are known as _____ they have inherited a secretor gene (SeSe or Sese).
secretors
(FORMATION OF A, B, AND H SOLUBLE ANTIGENS)
_______: codes for the production of the transferase α-2-L-fucosyltransferase
modifies the type 1 precursor substance in secretions to form H substance.
FUT 2 (Se) gene
(FORMATION OF A, B, AND H SOLUBLE ANTIGENS)
People who inherit the sese genotype are termed ______
nonsecretors.
(FORMATION OF A, B, AND H ANTIGENS ON RBCs WITH A, B, AND H SOLUBLE SUBSTANCES)
formation of soluble A, B, and H substances: _____ as the formation of A, B, and H antigens on the RBCs
- except for a few ______
same ; minor distinctions
(comparison of ABH antigens on RBCs with A, B, and H soluble substances)
RBC antigens can be glycolipids, glycoproteins, or glycosphingolipids.
ABH Antigens on RBCs
(comparison of ABH antigens on RBCs with A, B, and H soluble substances)
RBC antigens are synthesized only on type 2 precursor chains.
ABH Antigens on RBCs
(comparison of ABH antigens on RBCs with A, B, and H soluble substances)
Type 2 chain refers to a beta 1->4 linkage in which the number one carbon of the galactose is attached to the number four carbon of the N-acetylglycosamine sugar of the precursor substance.
ABH Antigens on RBCs
(comparison of ABH antigens on RBCs with A, B, and H soluble substances)
- The enzyme produced by the H (FUT1) gene (a-2-L-fucosyltransferase) acts primarily on type 2 chains, which are prevalent on the RBC membrane.
ABH Antigens on RBCs
(comparison of ABH antigens on RBCs with A, B, and H soluble substances)
Secreted substances are glycoproteins.
A, B, and H soluble substances
(comparison of ABH antigens on RBCs with A, B, and H soluble substances)
Secreted substances are primarily synthesized on type 1 precursor chains.
A, B, and H soluble substances
(comparison of ABH antigens on RBCs with A, B, and H soluble substances)
Type 1 chain refers to a beta 1->3 linkage in which the number one carbon of the galactose is attached to the number three carbon of the N-acetylgalactosamine sugar of the precursor substances.
A, B, and H soluble substances
(comparison of ABH antigens on RBCs with A, B, and H soluble substances)
The enzyme produced by the Se (FUT2) gene (a-2-L-fucosyltransferase) preferentially acts on type 1 chains in secretory tissues.
A, B, and H soluble substances
(ABO Typing Techniques)
SLIDE METHOD PRINCIPLE:
RBCs from the specimen are tested for presence of A antigen and/or B antigen using _______
________: presence of corresponding antigen on red blood cells
ANTI-SERA (Anti- A and Anti- B) ; Agglutination
(ABO Typing Techniques)
SLIDE METHOD REAGENTS
- ______________
Usually used in _________
Anti-A= ____
Anti- B= _____
Anti- A and Anti-B anti sera ; Forward Typing
blue ; yellow
(ABO Typing Techniques)
TUBE METHOD
Can be used for _____ AND ______
__________ and RECOMMENDED method
______ AND ________ can be performed to enhanced the reaction
Addresses the drying problem
Forward and Reverse typing ; GOLD STANDARD ; Incubation and centrifugation
(ABO Typing Techniques)
REVERSE TYPING METHOD
Detects: _________
Specimen: __________
Uses ___________
Antibody (A and B cells) ; Serum/plasma ; Red Cell Suspension
