GROUP 4 – C1

ABO BLOOD TYPEINCOMPATIBILITY

OUTLINE

I. Introduction

A. Definition of Terms

B. The Discovery of ABO Blood Group

II. The Red Blood Cell

A. Definition

B. Function

C. Cell Membrane and its Composition

1. Major Integral Proteins

2. Peripheral Membrane Proteins

3. Deformability

4. Permeability

III. Blood group Systems

A. ABO Blood Group System

B. ABH Antigens

1. Formation of H Antigen

2. Formation of A Antigen

3. Formation of B Antigen

C. Genetics in Determining Blood Type

IV. ABO TypingA. Blood typingB. Blood TransfusionC. Transfusion Reactions

Definition of Terms

• Antigen: A substance recognized by the body as being foreign, which can cause an immune response. Antigens are usually, but not exclusively, found on the red blood cell membrane.

• Antibody: A protein substance secreted by plasma cells that is developed in response to, and interacting specifically with, an antigen. Naturally occuring antibody: antibody present in a patient, without known prior exposure to the corresponding red blood cell antigen.

Definition of Terms

• Agglutinogen: A substance that stimulates the production of an agglutinin, thereby acting as an antigen.

• Agglutinin: An antibody that agglutinates cells.

 • Agglutination: The clumping together of red blood

cells or any particulate matter resulting from interaction of antibody and its corresponding antigen.

Definition of Terms

• Blood group: The type or specification of an individual’s blood according to the presence or absence of specific agglutinogens on the red cells

• Blood transfusion: The introduction of blood from one person into the circulation of another person

 • Incompatibility: When the agglutinogens on the red

cells in the donor react with the agglutinins in the recipient’s blood.

Definition of Terms

• Glycosyltransferases: are enzymes that facilitate the transfer of carbohydrate molecules onto carbohydrate precursor molecules.

 • Immunodominant sugar: in reference to glycoprotein

or glycolipid antigens, the sugar molecule that gives the antigen its specificity (e.g. galactose, which confers B antigen specificity).

Definition of Terms

• Amorph: a gene that does not appear to produce a detectable antigen; a silent gene such as Jk, Lu, O.

 • Allele: One of two or more different genes that may

occupy a specific locus in a chromosome.

 • Locus: the site of a gene at a chromosome.

Definition of Terms

• Forward typing/grouping: defined as using known sources of commercial antisera (anti-A, anti-B), to detect antigens on an individual’s RBCs.

• Reverse typing/grouping: defined as detection of ABO antibodies in the patient’s serum by using known reagent RBCs; namely A1 and B cells.

The Discovery of ABO Blood Group System

Karl Landsteiner

Alfred von DecastelloAdriano Sturli

THE RED BLOOD CELL

RED BLOOD CELL

• One of the 3 formed elements of blood

• Produced in the red bone marrow : erythropoiesis

RBC: Structural Characteristics

• Biconcave disc• Mature RBC: non-nucleated• No intracellular organelles such as

lysosomes, mitochondria or Golgi apparatus

• Size: - Mean diameter: 7.8 micrometers- Thickness: 2.5 micrometers (thickest

point), 1 micrometer (center)

RBC: Functions

• Major Function: Transport of hemoglobin (red, oxygen-containing pigment) into circulation

• Also contains carbonic anhydrase which helps in catalyzing carbonic acid (produced by tissues) to carbon dioxide and water for CO2 transport to excretion (exhalation).

• Responsible for most of the acid-base buffering power of the whole blood.

RBC: Cell Membrane

RBC: Cell MembraneTable 52–7. Summary of Biochemical Information About the Membrane of the Human Red Blood Cell (Harper’s Illustrated Biochemistry 28th ed.)

•The membrane is a bilayer composed of about 50% lipid and 50% protein.

•The major lipid classes are phospholipids and cholesterol; the major phospholipids are phosphatidylcholine (PC), phosphatidylethanolamine (PE), and phosphatidylserine (PS) along with sphingomyelin (Sph).

•The choline-containing phospholipids, PC and Sph, predominate in the outer leaflet and the amino-containing phospholipids (PE and PS) in the inner leaflet.

•Glycosphingolipids (GSLs) (neutral GSLs, gangliosides, and complex species, including the ABO blood group substances) constitute about 5–10% of the total lipid.

RBC: Cell Membrane

RBC MEMBRANE PROTEINS

Integral Proteins Peripheral Proteins

Glycophorin A Spectrin

Glycophorin B Actin (Band 5)

Glycophorin C Ankyrin (Band 2.1)

Anion-exchange-channel protein

(Band 3)

Band 4.1 and 4.2

Adducin

RBC: Cell Membrane

Integral Proteins

• Anion exchange protein (band 3)

- a transmembrane glycoprotein, with its carboxyl terminal end on the external surface of the membrane and its amino terminal end on the cytoplasmic surface.

Integral Proteins

• Glycophorins A, B and C- also transmembrane

glycoproteins but of the single-pass  type, extending across the membrane only once

- A is the major Glycophorin

Peripheral Proteins

• Spectrin- Major protein of the

cytoskeleton composed of 2 polypeptides: spectrin 1 and spectrin 2

- Has 4 binding sites: (1) for self-association, (2) for ankyrin (bands 2.1, etc), (3) for actin (band 5), and (4) for protein 4.1.

Peripheral Proteins

• Ankyrin

- Pyramid shaped protein that binds spectrin

Peripheral Proteins

• Actin (Band 5)- Exists in RBC as

short, double helical fragments of F-actin

- The tail end of Spectrin dimers binds to actin

- Actin also binds with Protein 4.1

Peripheral Proteins

• Protein 4.1- a globular protein, binds tightly to

the tail end of spectrin, near the actin-binding site of the latter, and thus is part of a protein 4.1-spectrinactin ternary complex.

- Protein 4.1 also binds to the integral proteins, glycophorins A and C, thereby attaching the ternary complex to the membrane. In addition, protein 4.1 may interact with certain membrane phospholipids, thus connecting the lipid bilayer to the cytoskeleton.

BLOOD GROUP SYSTEM

Blood Group System

• There are approximately 30 human blood group systems have been recognized, but the best known of which are the ABO, Rh (Rhesus), and MN systems and the most important is the ABO blood group.

• The term "blood group" applies to a defined system of red blood cell antigens (blood group substances) controlled by a genetic locus having a variable number of alleles (eg, A, B, and O in the ABO system) while the term "blood type" refers to the antigenic phenotype, usually recognized by the use of appropriate antibodies.

ABO Blood Group System

The most important in assuring a safe blood transfusion.

The table shows the four ABO phenotypes ("blood groups") present in the human population and the genotypes that give rise to them.

Blood Group

Antigens on RBCs

Antibodies in Serum Genotypes

A A Anti-B AA or AO

B B Anti-A BB or BO

AB A and B Neither AB

O Neither Anti-A and anti-B OO

ABH ANTIGENS

• Glycolipid in nature• Oligosaccharides attached directly to lipids on cell

membrane

• The A and B antigens are the last sugar added to the chain

• The "O" antigen is the lack of A or B antigens but it does have the most amount of next to last terminal sugar that is called the H antigen.

Formation of ABH Antigens

• results from the interaction of genes at three separate loci (ABO, Hh, and Se)

• Genes produce specific GLYCOSYLTRANSFERASES that add sugars to the basic precursor substance

Antigen Immunodominant sugar

Glcosyltransferase Gene

H L-fucose L- fucosyl transferase H

A N-acetyl-D-galactoseamine

N acetylgalactosaminyl

transferase

A

B D-galactose D- galactosyl transferase

B

Formation of ABH Antigens : Precursor Substance

• Type 2• Terminal galactose

attached toN-acetylglucosamine in a beta 1 – 4 linkage

Formation of ABH Antigens : “H” Antigen

“H” gene

α-2-L-fucosyltransferase

L-fucose

Formation of ABH Antigens : “A” Antigen

“A” gene

α-3-N-acetylgalactosaminyltransferase

N-acetyl-D-galactosamine (GalNAc)

Formation of ABH Antigens : “B” Antigen

“B” gene

α-3-galactosyltransferase

D-galactose

Genetics in Determining Blood Type

• The ABO gene is autosomal (the gene is not on either sex chromosomes)

• The ABO gene locus is located on the chromosome 9

• A and B blood groups are dominant over the O blood group

• Each person has two copies of genes coding for their ABO blood group (one maternal and one paternal in origin)

1 =  A/A          1 = Homozygous APhenotype AGenotype A/ACan Contribute Only an  A Gene to Offspring

           2 = A/O2 = Heterozygous APhenotype AGenotype A/0Can Contribute A or O Gene to Offspring

Inheritance Patterns

• A/A parent can only pass along A gene• A/O parent can pass along either A or O gene• B/B parent can only pass along B gene• B/O parent can pass along either B or O gene• O/O parent can only pass along O gene• AB parent can pass along either A or B gene

ABO Groups of the Offspring from the Various Possible ABO Matings

Mating Phenotypes Mating Genotypes Offspring Possible Phenotypes and Genotypes

A x A AA x AAAA x AOAO x AO

A(AA)A(AA or AO)A(AA or AO) or O (OO)

B x B BB x BBBB x BOBO x BO

B(BB)B(BB or BO)B(BB or BO) OR O(OO)

AB x AB AB x AB AB(AB) or A (AA) or B (BB)

O x O OO x OO O (OO)

A x B AA x BBAO x BBAA x BOAO x BO

AB (AB)AB (AB) or B (BO)AB (AB) or A (AO)AB (AB) or A (AO) or B (BO) or O (OO)

A x O AA x OOAO x OO

A (AO)A (AO) or O (OO)

A x AB AA x ABAO x AB

AB (AB) or A (AA)AB (AB) or A (AA or AO) or B (BO)

B x O BB x OOBO x OO

B (BO)B (BO) or O (OO)

B x AB BB x ABBO x AB

AB (AB) or B (BB)AB (AB) or B(BB or BO) or A (AO)

AB x O AB x OO A (AO) or B (BO)

BLOOD TYPING

Blood Typing

• Method to tell what specific type of blood an individual has

• Blood is often grouped according to the ABO blood typing system. This method breaks blood types down into four categories:• Type A• Type B• Type AB• Type O

2 Methods of Blood Typing

Forward Grouping

Reverse Grouping

Routine ABO Typing

Forward Grouping Reverse Grouping

Reaction of Cells Tested With

Red Cell ABO Group

Reaction of Serum Tested Against

Reverse ABO Group

Anti-A Anti-B   A1 Cells B Cells  

0 0 O + + O

+ 0 A 0 + A

0 + B + 0 B

+ + AB 0 0 AB

Forward Blood Grouping Reactions

Type “O” Reaction Type “A” Reaction

Type “B” Reaction Type “AB” Reaction

BLOOD TRANSFUSION

• determination of the patient’s correct ABO group is the most critical pre transfusion serologic test

• cross-matching must be done between Patient’s serum and Donor’s RBCs and vice versa

• For a blood transfusion to be successful ABO and Rh blood groups must be compatible between the donor blood and the patient blood

Who can receive blood from whom?

People with blood group 0 Rh - are called "universal donors" and people with blood group AB Rh+ are called "universal receivers.

Red Blood Cell Compatibility TableRecipient[1 Donor[1]

O− O+ A− A+ B− B+ AB− AB+

O−

O+

A−

A+

B−

B+

AB−

AB+

Table note Assumes absence of atypical antibodies that would cause an incompatibility between donor and recipient blood, as is usual for blood selected by cross matching.

TRANSFUSION REACTIONS

• diverse group of adverse reactions to transfusion that usually present during or shortly after transfusion

Febrile Nonhemolytic Reactions

• rise in temperature of 1°C or greater• chills or rigors

Allergic Reactions

• Mild allergic reactions to transfusion are common• symptoms include

• pruritus, • urticaria, • erythema, and • cutaneous flushing

Severe Allergic or Anaphylactic Reactions

• manifest cardiovascular instability• Hypotension• Tachycardia• loss of consciousness• cardiac arrhythmia• Shock• cardiac arrest

Acute Hemolytic Reactions (AHTRs)

• present within 24 hours of transfusion• Intravascular hemolysis is much more common in acute

hemolytic reactions than extravascular hemolysis• Signs:

• fever and chills, nausea, vomiting, pain, dyspnea, tachycardia, hypotension, bleeding, and hemoglobinuria

• Fever may be the initial sign of an AHTR• Renal failure is a later complication

Delayed Hemolytic Reactions (DHTRs)

• occur at least 24 hours after transfusion of the offending unit

• due to an anamnestic response to a red cell antigen to which the patient has previously made an antibody, the concentration of which was too low to detect in pretransfusion testing

• hemolysis is extravascular, but intravascular hemolysis may occur also

• less severe than AHTRs• clinical signs:

• fever or chills, jaundice, pain, or dyspnea

Bacterial Contamination of Blood Components

• When the donor’s blood is contaminated with large numbers of living organisms

• Often caused by psychrophilic organisms• onset of symptoms in most cases is during the

transfusion or shortly after it• Signs:

• Fever, chills, hypotension, shock, nausea, and vomiting

• Dyspnea, pain, and diarrhea may occur also

Transfusion-associatedCirculatory Overload

• Too common and preventable transfusion reaction• presents as congestive heart failure during or shortly

after transfusion• Signs and symptoms:

• dyspnea, orthopnea, cyanosis, tachycardia, elevated blood pressure, pulmonary edema, jugular venous distention, pedal edema, and headache

• patients with pre-existing heart disease are at risk of circulatory overload with transfusion

Transfusion-Transmitted Diseases

• HIV/AIDS• Hepatitis• Human T Cell Lymphotropic Virus (HTLV I/II)• Cytomegalovirus• Malaria• Syphilis

References

• Harper’s Illustrated Biochemistry 28th ed.• Modern Blood Banking and Transfusion Practices

(Denise M. Harmening) 5th ed.• Medical Physiology (Guyton and Hall) 11th ed.• Henry’s Clinical Diagnosis and Management by

Laboratory Methods

THANK YOU

APPENDICES

ABO Blood Types