ABO Blood Group System

acute intravascular hemolysis

renal failure

death

Transfusion of incompatible blood is associated with what? (3)

acute humoral rejection

Transfusion of incompatible organs is associated with what?

(aka: graft vs host disease)

chromosome 9

Which chromosome is the ABO gene on?

A, B, AB, O

What are the 4 phenotypes resulting from the presence or absence of A or B antigens?

A or B antigens

The phenotype of blood is determined by the presence or absence of what?

AA, AO, BB, BO, AB, OO

What are the 6 genotypes possible for the ABO blood groups?

O

Which gene is an amorphic gene?

no detectable antigens

What makes the O gene amorphic?

autosomal recessive

group O phenotype is an __________ __________ trait

glycoprotein

What is the structure that commonly carries ABO and H antigens on the red blood cell membrane?

glycoprotein

protein with carbohydrate attached

RBC

platelets

lymphocytes

ABO antigens are found on what 3 cells?

**they are also found on most epithelial/endothelial cells & organs

kidneys

heart

bowel

pancreas

lungs

What 5 organs are ABO antigens found?

tissue cells

Soluble forms of ABO antigens are also synthesized and secreted by what type of cells?

**this is why they are also found in association with cellular membranes

cerebral spinal fluid

soluble forms of ABO antigens are detectable in all secretions & body fluids EXCEPT

5-6 weeks gestation

When do ABO antigens show up in an embryo?

2-4 years

Between what age group do you have adult levels of ABO antigens present?

(fully developed antigens)

3-6 months

When do the ABO antibodies start to develop?

5-10 years

When do the ABO antibodies peak?

true

True or False:

ABO antibodies are NOT present at birth

true

True or False:

ABO antibodies are naturally occurring

isohemagglutinins

aka naturally occurring antibodies

abs against A or B ags that individuals lack

A antigen

If you have Anti-B, what antigen will be present?

B antigen

If you have Anti-A, what antigen will be present?

AB antigen

If you have NO antibodies, what antigen will be present?

O antigen

If you have Anti-A, Anti-B, or Anti-A,B, what antigen will be present?

IgM

What type of immunoglobulin are anti-A and Anti-B?

IgG

What type of immunoglobulin are anti-O (anti-A,B)?

IgM & IgG3

What 2 ABO antibodies activate complement?

anti-A,B

What antibody is not a combination of anti-A and anti-B, but is a different "cross-reacting antibody" that is usually IgG?

anti-A1

Which antibody can sometimes be found in people with subgroups of A?

cold; react at RT

What temperature do ABO antibodies react at?

gut & environmental bacteria

What is the source of ABO antibodies?

**HINT: they have ABO-like antigenic structures on their surfaces, which stimulate the immune system in infants

ex: Enterobacteriaceae

type I chain

precursor chain that ABO blood group is built on that floats free in secretions (saliva, tears, urine, digestive fluids (except CSF) as glycoproteins)

Glycolipids in plasma

Galactose sugar attaches on B1-3

type II chain

precursor chain that ABO group is built on that is attached to RBC membrane

Mixture of glycolipids and glycoprotein (predominant) and attach by carbohydrate

Galactose sugar attaches at B1-4

Chain tested for in ABO testing

H gene

Se gene

ABO gene

What are the 3 genes that modify precursor chains?

H gene

found on chromosome 19

results in the formation of H antigen

Fut 1 gene

the H gene is also known as...

true

True or False:

We need H gene for everything to build up

Se gene

secretor gene found on chromosome 19

-- affects type I chains in fluids & secretions (allows them to have ags)

-- acts as an extra barrier of immune protection

Fut 2 gene

the Se gene is also known as...

ABO gene

found on chromosome 9

-- affects type II chains

glycosyltransferases

H, Se, ABO do NOT code to produce ags. Instead, they code to produce a specific enzyme that add sugars to precursors

immunodominant sugars

sugars that are added to the precursor chains

determine ABO blood groups

Why are immunodominant sugars important?

H

Glycosyltransferase:

α-2-L-fucossyltransferase

A

Glycosyltransferase:

α-3-N-acetylgalactosaminyltransferase

B

Glycosyltransferase:

α-3-D-galactosyltransferase

L-Fucose

What is the immunodominant sugar of H gene?

N-acetyl-D-galactosamine

What is the immunodominant sugar of A gene?

D-galactose

What is the immunodominant sugar of B gene?

RBC

Which precursor structure is this?

H antigen

Which antigen is formed?

A antigen

Which antigen is formed?

B antigen

Which antigen is formed?

AB antigen

Which antigen is formed?

H antigen

What antigen is the platform of A and B antigen?

H

the only antigen in the H blood group system

2 significant alleles: H and h

H

Which allele in the H blood group system is dominant

(99.99%)

h

Which allele in the H blood group system is recessive

(amorph & really rare!!)

O

Which blood group has the highest concentration of the H antigen?

AB

Which blood group has the lowest concentration of the H antigen?

type II

Which type of chain is ABH antigens constructed on?

**hint: located on the red blood cell

Bombay

rare autosomal recessive phenotype characterized by the absence of H, A, and B ag on RBCs and in secretions (Se gene)

-- NO H ag formed (no L-fucose sugar attached on their chain), so no A or B ag can be formed

-- patient will type O

-- ab in serum: anti-A, anti-B, anti-A,B, anti-H

-- will agglutinate ALL ABO blood types

hh sese

What is the genotype of a Bombay individual?

other Bombay blood

What blood can a Bombay patient be transfused with?

Para-Bombay

small amount of A and/or B ag on RBC

-- have at least one Se in genotype

-- Se gene produces L-fructosyltransferase that can act on type I chains in fluids & secretions

-- this can be converted into A and/or B ag depending on ABO genes inherited

-- have H, A, and/or B ag in their secretions which can get absorbed from plasma on the RBC membrane resulting in weak expression

absorption & elution studies

How is Bombay detected?

hh Sese

What is the genotype of a Para-Bombay individual?

SeSe or Sese

What genotypes will a secretor have if they have at least one Se in their secretion?

sese

What genotypes will a secretor if they have no ag in their secretion?

soluble ABH

What type of antigens can be found in blood secretions?

Fut 2

Which gene encodes for mucosal protective functions and determines the ability to secrete your blood type ag in body fluid and tissue?

A, B, H

Which antigen in plasma can absorb on platelets and lymphocytes but not on granulocytes and monocytes

lack IgA

In non-secretors, how is the degree of protection decreased?

- less resistant to infection by H. pylori

- ↑ risk of developing celiac disease

- ↑ respiratory system issues such as asthma or viruses

- ↑ autoimmune disease (like multiple sclerosis)

- ↑ heart disease & diabetes

- ↑ UTI and yeast infection

forward typing

testing the red cells for the presence of A and/or B ag using reagent anti-A & anti-B

- Ag = pt RBC

- Ab = antisera (ie: anti-A)

reverse typing

testing the serum/plasma for the present of ABO ab using A1 & B cells

- Ag = antisera (ie: anti-A)

- Ab = pt plamsa/serum

A and/or B ag

Phenotype is determined when red blood cells are directly tested for what?

subgroup A

Which subgroups are more common: A or B?

A1 and A2

What are the 2 most common subgroups of A?

anti-A

A1 and A2 both agglutinate strongly by what?

A2 cells

Which subgroup (A1 or A2) show increased reactivity with the anti-H?

lectin Dolichos biflorus

What would you use to distinguish the difference between subgroups A1 and A2?

A1

A1 vs A2 subgroup

anti-A and anti-A1 (lectin) rxt

A2

A1 vs A2 subgroup

only anti-A rxts

A subgroup

- infrequently encountered

- recognized due to ABO discrepancies (ie: forward/reverse don't match)

- decrease number of Ag sites

- variable agglutination with anti-A,B

- variable detection of anti-H

- anti-A1 may or may not be present

B subgroup

- extremely rare

- recognized due to ABO discrepancies

- variation of rxn to anti-B and anti-A,B

criteria to differentiate:

- strength of agglutination between anti-B, anti-A,B, and anti-H

- absorption/elution studies with anti-D

- molecular testing

lectins

seed extracts that act as anti-sera for Ag typing (act as IgM abs)

Dolichos biflorus

Which lectin binds A1 (and A1B)?

Ulex europaeus

Which lectin binds H O cells?

Bandeiraea simplicifolia

Which lectin binds B?

Vicia graminea

Which lectin binds N?

Iberis amara

Which lectin binds M?

transfusion medicine

branch of medicine that encompasses all aspect of blood/blood related components (including anything related to hemovigilance)

true

True or False:

Blood that is transfused is technically considered a drug (regulated by the FDA)

Karl Landsteiner; 1900

Who discovered the ABO blood group system and when?

normal, healthy individuals possess ABO antibodies to the ABO blood group antigens absent from their red blood cells

What does Karl Landsteiner's rule on ABO state?

carb

Carb or Protein ags?

ABO, H, Le, I, P1PK, Glob

protein

Carb or Protein ags?

Fy (Duffy), Jk (Kidd), Kel (Kell), Rh, MNS