BB 3: ABO Blood Group System

CEREBRO BB Notes: Pages 7-9

Karl Landsteiner (1901)

discovered ABO blood group

001

ISBT number of ABO

ABO gene

the gene that encodes for the precursor of an enzyme that adds sugar to precursor substance

chr 9

location of ABO locus

H gene

the formation of this gene serves as the biosynthetic precursor for the formation of A and B antigens

chr 19

location of H locus and secretor locus

H antigen

precursor of the ABO blood group antigens

Secretor gene

the gene for expression of ABH antigens on body fluids

Secretor

Secretor or Non-secretor?

SeSe

Secretor

Secretor or Non-secretor?

Sese

Non-secretor

Secretor or Non-secretor?

sese

L-fucose

immunodominant sugar for H antigen

N-acetyl-D-galactosamine

immunodominant sugar for A antigen

D-galactosamine

immunodominant sugar for B antigen

α-2-L-fucosyltransferase

glycosyltransferase for the production of H antigen

α-3-N-acetylgalactosaminyltransferase

glycosyltransferase for the production of A antigen

α-3-D-galactosaminyltransferase

glycosyltransferase for the production of B antigen

False; Type O

Modified True or False:

If a person is Type AB, the H antigen remains unmodified.

37th day

ABO antigens are formed on the __ day of fetal life.

• glycolipids / glycoproteins

• Type 2 chain paragloboside

composition of ABO antigens in RBCs

• glycolipids / glycoproteins

• Type 1 chain paragloboside

composition of ABO antigens in secretions

Trypan blue

dye in Anti-A reagent

Acriflavine yellow

dye in Anti-B reagent

Forward Typing

Detection of ABO antigens

3-6 months

Formation of ABO antibodies begin ___ months after birth.

5-10 years old

ABO antibodies peak production during ___ years old.

IgM, IgG, IgA

Nature of ABO antibodies

IgM

Most predominant nature of ABO antibodies

Reverse Typing

unique lab detection for ABO blood group

Reverse Typing

also called serum typing

A1 cells

Reagent for the detection of Anti-A in serum typing

B cells

Reagent for the detection of Anti-B in serum typing

Type AB

Anti-A	Anti-B	A1 cells	B cells
4+	4+	0	0

Type O

Anti-A	Anti-B	A1 cells	B cells
0	0	4+	4+

O gene

considered as the amorph gene in ABO blood group

Hemagglutination Inhibition

principle of the determination of secretory property

Saliva

specimen for the determination of secretory property

A, B, and O cells

indicator cells

Anti-A, Anti-B, and Anti-H

diluted anti-sera

No agglutination

Positive result, indicating the individual is secretor

Agglutination

Negative result, indicating that the individual is non-secretor

Punnett Square

tool used in the determination of the possible blood type of an offspring

Anti-B

common antibody in A1 and A2 subgroup

A2

A subgroup that possesses Anti-A1

Dolichos biflorus

source of Anti-A1 lectin

Ulex europaeus

source of Anti-H lectin

• Maclura aurantiaca

• Iberis amara

source of Anti-M lectin

Vicia graminea

source of Anti-N lectin

• A3

• Ax

• Aend

• Ael

weak A subgroups that produce Anti-A1

Bombay phenotype

absence of H gene, causing non-expression of ABH antigens

• hh

• Oh

• Hnull

symbols of Bombay phenotype

• Anti-A

• Anti-B

• Anti-A,B

• Anti-H

antibodies present in the serum of Bombay blood group

IgM

nature of Anti-H

hh sese

genotype of Classical Bombay

hh Se

genotype of Para-Bombay

Type O

Anti-A	Anti-B	A1 cells	B cells	Anti-H lectin	O cells
0	0	4+	4+	4+	0

Bombay (Oh)

Anti-A	Anti-B	A1 cells	B cells	Anti-H lectin	O cells
O cells	0	4+	4+	0	4+

Type O

ABO blood group most reactive to Anti-H lectin due to greatest concentration of H antigen

Type A1B

ABO blood group least reactive to Anti-H lectin due to lowest concentration of H antigen

Group I ABO Discrepancy

Missing or weakly reactive Ab

Group II ABO Discrepancy

Missing or weakly reactive Ag

Group III ABO Discrepancy

Plasma protein abnormalities

Group IV ABO Discrepancy

Miscellaneous problems

Reverse Typing

problem in Group I ABO Discrepancy

Forward Typing

problem in Group II ABO Discrepancy

Rouleaux Formation

problem seen microscopically in Group III ABO Discrepancy

Forward & Reverse Typing

problem in Group IV ABO Discrepancy

Group I ABO Discrepancy

Conditions related to this ABO Discrepancy:

• Newborns, elderly patients

• Agammaglobulinemia

• Hypogammaglobulinemia

• Dilution of ABO antibodies

Group II ABO Discrepancy

Conditions related to this ABO Discrepancy:

• Leukemia, Hodgkin’s disease

• A/B subgroups

• Acquired B phenomenon

• Excessive amount of BGSS

Group III ABO Discrepancy

Conditions related to this ABO Discrepancy:

• Multiple myeloma

• Waldenstrom’s macroglobulinemia

• Increased fibrinogen levels

• Wharton’s jelly contamination

Group IV ABO Discrepancy

Conditions related to this ABO Discrepancy:

• Cold-reactive autoantibodies

• Unexpected antibodies

• Cis-AB

Group I ABO Discrepancy

Anti-A	Anti-B	A1 cells	B cells	O cells	AC
4+	0	0	0	0	0

Extend the incubation time of reverse typing mixture for 15-30 mins. at room temp.

resolution for Group I ABO Discrepancy

Group II ABO Discrepancy

Anti-A	Anti-B	A1 cells	B cells	O cells	AC
0	+/-	4+	0	0	0

Extend the incubation time of forward typing mixture for 15-30 mins. at room temp.

resolution for Group II ABO Discrepancy

Group II ABO Discrepancy - Acquired B phenomenon

Anti-A	Anti-B	A1 cells	B cells	O cells	AC
4+	2+	0	4+	0	0

1. Acidify Anti-B reagent

2. Secretor studies

3. Addition of acetic anhydride to Px reds cells

resolution for Acquired B phenomenon

E. coli serotype O86

bacteria related to Acquired B phenomenon due to modification of NAG on A antigen

N-acetyl-D-galactosamine

the sugar modified in Acquired B phenomenon, resulting to a pseudo-B antigen

Group III ABO Discrepancy

Anti-A	Anti-B	A1 cells	B cells	O cells	AC
4+	4+	2+	2+	2+	2+

Saline dilution / washing of RBCs

resolution for Group III ABO Discrepancy

Group IV ABO Discrepancy

Anti-A	Anti-B	A1 cells	B cells	O cells	AC
2+	4+	4+	2+	2+	2+

1. Prewarming of test components at 37°C

2. Addition of sulfhydryl reagents (DTT, 2-ME)

3. Adsorption of cold-reactive antibodies using RESt

resolution for Group IV ABO Discrepancy

Mycoplasma pneumoniae

bacteria related to Group IV ABO Discrepancy