ABO and Rh Blood Group

discovered in 1901 by _

Karl Landsteiner

Genes involve for expression

• ABO gene - chromosome 9, encodes for production of enzyme that transfer a sugar to the basic precursor substance to form the antigen

• H gene - chromosome 19, encodes for production of enzyme that transfer a sugar to the basic precursor substance to form the antigen

• Se gene - chromosome 19, determines the ability to express the ABH antigens on body secretions/fluids

H gene

• glycosyltransferase: _

• immunodominant sugar:_

• antigen:_

• glycosyltransferase: a-2-L-fucosyltransferase

• immunodominant sugar:L-fucose

• antigen: H

A gene

• glycosyltransferase: _

• immunodominant sugar:_

• antigen:_

• glycosyltransferase: a-3-N-acetylgalactosaminyltransferase

• immunodominant sugar: N-acetyl-D-galactosamine

• antigen: A

B gene

• glycosyltransferase: a-3-D-galactosyltransferase

• immunodominant sugar: D-galactose

• antigen: B

_ is the biosynthetic precursor needed in the formation of A and B antigen

it is present in >99.99% of the population

H antigen

ANTIGENS

• Formation:

• Composition:

• Lab detection:

• Formation: 37th day of fetal life

• Composition:

RBC

→glycolipids/glycoproteins

→type 2 chain paragloboside

SECRETIONS

→glycoproteins

→Type 1 chain paragloboside

• Lab detection:

→Forward/Cell Typing

→Reagents: Anti-A, Anti-B

ANTIBODY

• Formation:

• Composition:

• Lab detection:

ANTIBODY

• Formation:

→Detectable: 3 to 6 months old

→Peak: 5 to 10 years old

• Composition: predominantly IgM with mixture of IgG and IgA

• Lab detection:

→Reverse/Serum Typing

→A1 cells, B cells

ABO Mating

• determines the possible blood type of an offspring

• Tool: _

Punnett square

A subgroups

• A1

• A2

A1

• %:

• Antigens present:

• Common antibody:

• Unexpected antibody:

• Reaction with anti-A1 lectin:

• %: 80%

• Antigens present: A and A1

• Common antibody: Anti-B

• Unexpected antibody: None

• Reaction with anti-A1 lectin: 4+

A2

• %:

• Antigens present:

• Common antibody:

• Unexpected antibody:

• Reaction with anti-A1 lectin:

• %: 20%

• Antigens present: A

• Common antibody: Anti-B

• Unexpected antibody: Anti-A1

• Reaction with anti-A1 lectin: 0

_ - seed extracts that can agglutinate human cells with some degree of specificity

Ex: (4)

LECTINS - seed extracts that can agglutinate human cells with some degree of specificity

Ex:

• Anti-A1 → Dolichos biflorus

• Anti-H →Ulex europaeus

• Anti-M → Iberis amara/Maclura aurantiaca

• Anti-N →Vicia graminea

• symbols include hh, Oh, Hnull

• absence of H gene causes non-expression of ABh antigens

→RBCs = absence of ABH antigens

→Serum = presence of anti-A, anti-B, anti-A,B, anti-H

Bombay phenotype

Differentiation of Type O and Bombay

• Reaction with anti-H lectin

Type O - 4+

Bombay - 0

Arrange blood type by decreasing H antigen and reactivity to anti-H lectin

O > A2 > B > A2B > A1 > A1B

Types of ABO Typing Discrepances

• Group I - Missing or Weakly Reacting Antibody

• Group II - Missing or Weakly Reacting Antigen

• Group III - Plasma protein abnormalities

• Group IV - Miscellaneous problems

Group I

→Causes:

→Resolution:

→Causes:

• newborns, elderly patients

• bruton's agammaglobulinemia

• hypogammaglobulinemia

• dilution of ABO antibodies

→Resolution:

• extend the incubation time of reverse typing mixture for 15 to 20 mins at room tempt

Group II

→Causes:

→Resolution:

→Causes:

• leukemia, hodgkin's cells

• A/B subgroups

• acquired B phenomenon

• excessive amount of BGSS

→Resolution:

• extend incubation time of forward typing for 15 to 30 minutes at room tempt.

Group III

→Causes:

→Causes:

• multiple myeloma

• waldenstrom's

• high fibrinogen levels

• wharton's jelly

• rouleaux

Group IV

• Causes:

• cold-reactive autoantibodies

• unexpected antibodies

• Cis-AB

Acquired B Phenomenon

• Resolution:

Resolution:

• acidify anti-B reagent

• secretor studies

• addition of acetic anhydride to patient's red cells

Rouleaux formation

• Resolution:

• Wash with saline

Wharton's Jelly (viscous mucopolysaccharide material present in cord blood)

• Resolution:

Resolution:

• wash cord cells with NSS 6 - 8x

Cold Reactive Autoantibodies

• Resolution:

Resolution:

• Prewarming of test components at 37C

• Add sulfhydryl reagents (DTT, 2-ME)

• Adsorb cold-reactive antibodies using RESt

Rh Blood Group (004)

• genes involved for expression of antigens

• RHD gene - D antigen

• RHCE gene - C,c, E, e antigens

• RHAG gene - Rh-asscoiacted glycoprotein (co-expressor)

Rh Nomenclatures

• _ - 5 Rh antigens, d= absence of D antigen

• _ - 8 agglutinogens with equivalent blood factors

• _ - no genetic basis, presence/absence of antigen

• _ - machine readable, uniform nomenclature

• FISHER-RACE - 5 Rh antigens, d= absence of D antigen

• WIENER - 8 agglutinogens with equivalent blood factors

• ROSENFIELD - no genetic basis, presence/absence of antigen

• ISBT - machine readable, uniform nomenclature

Weak D

• red cells carrying the weak D antigen have historically been referred to as the _ type

• testing for weak D utilizes the principles of _ and diluent control should also be tested

• testing is required for: (2)

• red cells carrying the weak D antigen have historically been referred to as the Du type

• testing for weak D utilizes the principles of IAT and diluent control should also be tested

• testing is required for:

→blood donors

→babies born from Rh-negative mothers

Weak D (Types)

• _ - only few antigens are present on RBCs

• _ - D gene is in opposite position to C gene

• _ - missing portion of D antigen molecule

• Quantitative/Genetic Weak D - only few antigens are present on RBCs

• C Trans / Position Effect - D gene is in opposite position to C gene

• Partial D / D Mosaic - missing portion of D antigen molecule

Immunogenenicity of Rh antigens

D>c>E>C>e

Rh unusual Phenotypes and Rare alleles

• _ - lacks all Rh antigens, demonstrate mild hemolytic anemia and stomatocytosis

• _ - partial suppression of Rh gene; features similar to Rh null but less severe

• _ - noC/c or E/e reactivity; unusually strong D expression

• _ - compound antigen: c and e in cis position

• _ - compound antigen: C and e are in cis position

• Rh null - lacks all Rh antigens, demonstrate mild hemolytic anemia and stomatocytosis

• Rhmod - partial suppression of Rh gene; features similar to Rh null but less severe

• Exalted D - noC/c or E/e reactivity; unusually strong D expression

• f - compound antigen: c and e in cis position

• rhi - compound antigen: C and e are in cis position