ABO Incompatibility

ABO BLOOD TYPE INCOMPATIB IL ITY

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OVERVIEWI. Introduction

A. Definition of Terms

B. The Discovery of ABO

II. The Red Blood Cell

A. Definition

B. Function

C. Composition

1. Major Integral Proteins

2. Peripheral Membrane Proteins

III. Blood group Systems

A. Definition of terms

B. ABO blood group

C. Antigens

1. ABH Antigen

2. H Antigen

a. Bombay Group

3. ABO Substances

a. Glycosphingolipis

b. Glycoproteins

4. How do you make an Antigen? a. Precursor Substance b. Biochemical Structure of H Antigen c. Biochemical Structure of A Antigen d. Biochemical Structure of B Antigen

5. Composition of Antigen6. Genetics in ABO

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

V . Recap (by guide questions)

DEFINITION OF TERMS

Antigen: Any substance that when introduced in to, or present in, the tissues or blood causes the formation of antibodies and only reacts with its specific antibodies

Antibody: A protein produced by certain cells of the body in the presence of a specific antigen. The antibody combines with that antigen to inhibit, neutralize or destroy it

Agglutinogen: An antigen located on the surface plasma membrane of RBC which determines the blood group of the individual.

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DEFINITION OF TERMS

Agglutinin: A specific antibody in blood plasma capable of causing the clumping of RBC or bacteria or particles such as viruses

Agglutination: The clumping together of blood cells or microorganisms, usually due to an antigen-antibody reaction

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

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DEFINITION OF TERMS

Blood transfusion: The introductioof 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.

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THE DISCOVERY OF ABO

Karl Landsteiner(1868-1943)

A, B, O

Sturle and Von Descatello

AB

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THE RED BLOOD CELL

Nonnucleated

Biconcave in shape (This shape increases the surface-to-volume ratio of the red blood cell, thus facilitating gas exchange. )

Has simpler structure than most human cells, essentially composed of a membrane surrounding a solution of hemoglobin.

No intracellular organelles, such as mitochondria, lysosomes, or Golgi apparatus

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FUNCTIONS OF THE RED BLOOD CELL

Delivers oxygen to the tissues

Helps in the disposal of carbon dioxide and protons formed by tissue metabolism.

life span -120 days

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RBC COMPOSITION

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RBC COMPOSITIONTable 52–7. Summary of Biochemical Information About the Membrane of the Human Red Blood Cell

•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.

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RBC COMPOSITION

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RBC COMPOSITIONTable 52–7. Summary of Biochemical Information About the Membrane of the Human Red Blood Cell (CONT)

•Analysis by SDS-PAGE shows that the membrane contains about 10 major proteins and more than 100 minor species•The major proteins (which include spectrin, ankyrin, the anion exchange protein, actin, and band 4.1)•Many of the proteins are glycoproteins (eg, the glycophorins) containing O- or N-linked (or both) oligosaccharide chains located on the external surface of the membrane.

Harper’s Illustrated Biochemistry, 28e

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PRINCIPAL PROTEINS OF THE RED CELL MEMBRANE

Band Number1

 Protein Integral (I) or

Peripheral (P)Approximate Molecular Mass (kDa)

1 Spectrin (a ) P 240

2 Spectrin (B) P 220

2.1 Ankyrin P 210

2.2 Ankyrin P 195

2.3 Ankyrin P 175

2.6 Ankyrin P 145

3 Anion exchange protein I 100

4.1 Unnamed P 80

5 Actin P 43

6 Glyceraldehyde-3-phosphate dehydrogenase

P 35

7 Tropomyosin P 29

8 Unnamed P 23

Glycophorins A, B, and C I 31, 23, and 28

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THE MAJOR INTEGRAL PROTEINS OF THE RBC

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.

a multipass membrane protein, extending across the bilayer approximately fourteen times

exists as a dimer in the membrane, in which it forms a tunnel, permitting the exchange of chloride for bicarbonate. Carbon dioxide, formed in the tissues, enters the red cell as bicarbonate, which is exchanged for chloride in the lungs, where carbon dioxide is exhaled.

The amino terminal end binds many proteins, including hemoglobin, proteins 4.1 and 4.2, ankyrin, and several glycolytic enzymes. Purified band 3 has been added to lipid vesicles in vitro and has been shown to perform its transport functions in this reconstituted system.

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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, is made up of 131 amino acids, and is heavily glycosylated (about 60% of its mass).

Its amino terminal end, which contains 16 oligosaccharide chains (15 of which are O-glycans), extrudes out from the surface of the red blood cell. Approximately 90% of the sialic acid of the red cell membrane is located in this protein.

The carboxyl terminal end extends into the cytosol and binds to protein 4.1, which in turn binds to spectrin.

Glycophorin A contains binding sites for influenza virus and for Plasmodium falciparum, the cause of one form of malaria. Intriguingly, the function of red blood cells of individuals who lack glycophorin A does not appear to be affected.

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THE PERIPHERAL MEMBRANE PROTEINS

Spectrin major protein of the cytoskeleton, composed of two polypeptides:

spectrin 1 ( chain) and spectrin 2 ( chain). These chains, measuring approximately 100 nm in length, are

aligned in an antiparallel manner and are loosely intertwined, forming a dimer.

Both chains are made up of segments of 106 amino acids that appear to fold into triple-stranded -helical coils joined by nonhelical segments.

One dimer interacts with another, forming a head-to-head tetramer. The overall shape confers flexibility on the protein and in turn on the membrane of the red blood cell. At least four binding sites can be defined in spectrin: (1) for self-association, (2) for ankyrin (bands 2.1, etc), (3) for actin (band 5), and (4) for protein 4.1.

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Ankyrin

pyramid-shaped protein that binds spectrin. In turn, ankyrin binds tightly to band 3, securing attachment of spectrin to the membrane. Ankyrin is sensitive to proteolysis, accounting for the appearance of bands 2.2, 2.3, and 2.6, all of which are derived from band 2.1.

Actin (band 5)

exists in red blood cells as short, double-helical filaments of F-actin. The tail end of spectrin dimers binds to actin. Actin also binds to protein 4.1.

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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.

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Interaction of cystoskeletal proteins with each other and with certain integral proteins of the RBC.

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BLOOD GROUP SYSTEMS

Discovered by Landsteiner 30 human blood group systems have been recognized, the

best known of which are the ABO, Rh (Rhesus), and MN systems.

"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).

"blood type" refers to the antigenic phenotype, usually recognized by the use of appropriate antibodies.

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DEFINITION OF TERMS Glucosyltransferase:

are enzyme that facilitate the transfer of carbohydrate molecules onto carbohydrate precursor molecules.

Immunodominant sugar:

is the sugar molecule that completes the antigenic determinant when combined with the precursor substance.

Amorph:

a mutant allele that has little or no effect on the expression

of a trait

Allele:

any alternate form of a gene that can occupy a given chromosomal location (Locus).

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ABO BLOOD GROUP SYSTEM

Based on two agglutinogens referred to as A and B. Individuals whose erythrocytes develop only Antigen A are

said to have blood type A. Those whose erythrocytes develop only agglutinogen B are

said to have blood group B. Some individuals, who have erythrocytes which develop both

agglutinogen A and B, are said to have blood group AB. Those individuals who manufacture neither agglutinogen are

said to have blood group O.

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The blood group agglutinins, a and b, are present in the plasma of the individuals.

Blood group A plasma contains agglutinin b. Blood group B plasma contains agglutinin a. Blood group AB contains neither of the agglutinin. Blood group O contains both agglutinin a and b.

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RED CELL ANTIGEN

Antigens are inherited

Real function unknown

Damn important during transfusion

Lots of antigens exist (grouped into systems)

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BLOOD TYPE (OR BLOOD GROUP) IS DETERMINED, IN PART, BY THE ABO BLOOD GROUP ANTIGENS PRESENT ON RED BLOOD CELLS

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ABH ANTIGEN The inheritance of ABO blood group

demonstrates that each individual inherits ABO gene from each parent and these two genes will determine the antigen present on RBC membrane.

One position or locus on each chromosome 9 is occupied by A, B, or O gene.

A locus termed H and the final product of the genes at that locus is H antigen. It is necessary for the expression of normal ABO antigens.

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H ANTIGEN Basic structure molecule Required to produce either A and B antigens Detected using a specific antisera (lectin seed extract known

as Ulex europeaus) Each parent contributes one gene either, H or h. Giving

possible genetic combinations HH, Hh or hh.

*PS = oligosaccharide chain attached to glycosphingo-lipid, Type 2 chain (on RBC)

H gene acts on a Precursor substance(PS)* by adding Fucose

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H ANTIGEN

HH and Hh will produce the H antigen hh do not produce the H antigen and will

have the Bombay phenotype

H h

H HH Hh

h Hh hh

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BOMBAY GROUP

A very rare cases Red cells that are not agglutinated by Anti-A,

Anti-B, or Anti-AB Believed to be formed under the influence of

suppressor gene and are characterized by reactions resembling those of O cells

The plasma contains Anti-A and Anti-B, but the cells do not react with Anti-H or with Anti-A or Anti-B

Differentiation is based on the presence of Anti-H in the plasma and a lack of H substance on the cells

Normal group O blood do not possess Anti-H in the plasma, but do contain H substance on the cells

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BOMBAY GROUP

Cells Contain Serum Contains

Bombay Group -----------------Anti-A1

Anti-BAnti-H

Group O H Substance Anti-A1

Anti-B

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ABO SUBSTANCES :GLYCOSPHINGOLIPIDS & GLYCOPROTEINS

ABO substances Are complex oligosaccharides present in most cells of the body and in certain

secretions On membranes of red blood cells, the oligosaccharides that determine the

specific natures of the ABO substances appear to be mostly present in glycosphingolipids

whereas in secretions the same oligosaccharides are present in glycoproteins. Their presence in secretions is determined by a gene designated Se (for

secretor ), which codes for a specific fucosyl (Fuc) transferase enzyme that adds fucose onto Type I chains primarily in secretory glands. Individuals of SeSe or Sese genotypes secrete A or B antigens (or both), whereas individuals of the sese genotype do not secrete A or B substances, but their red blood cells can express the A and B antigens.

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HOW DO YOU MAKE AN ANTIGEN?

Start with a protein precursor

Add fucose to make H antigen

Add N-acetylgalactosamine to H Ag to make A Ag

Add galactose to H Ag to make B Ag

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Biochemical structure of Precursor Substance

A, B and H antigens are built on oligosaccharide chains of 4 types. The most common forms are Type 1 and Type 2.

Type 1: Carbon one of Gal is attached to the carbon three of GlcNAc.

Type 2: Carbon one of Gal is attached to the carbon four of GlcNAc.

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Biochemical structure of H antigen

Precursor Substance-Oligosaccharide chain

H gene acts on a Precursor substance(PS) by adding Fucose

L-fucosyl transferase

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Biochemical structure of A antigen

H gene acts on a Precursor substance(PS) by adding Fucose

N-acetyl-galactosamine added to H substance

Precursor substance- oligosaccharide chain

GalNAc transferase

L-fucosyl transferase

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Biochemical structure of B antigen

H gene acts on a Precursor substance(PS) by adding Fucose

D-galactose added to H substance

D- galactosyl transferase

Precursor Substance -oligosaccharide chain

L-fucosyl transferase

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Blood Group O people have red blood cells rich in H antigen. Why?

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Donor Nucleotides & Immundominant Sugars responsible for H, A, and B Ags specificity

Antigen Immunodominant sugar Nucleotide Glcosyltransferase Gene

H L-fucose Guanosine

GDP-FUC L- fucosyl transferase

H

A N-acetyl-D-galactoseamine

Uridine

UDP-GALNAC

N acetylgalactosaminyl

transferaseA

B D-galactose Uridine

UDP-GALD- galactosyl transferase

B

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ABO Genetics

1. Hh gene – H and h alleles (h is an a morph)

2. Se gene – Se and se alleles (se is an amorph)

3. ABO genes– A, B and O alleles

1. Controls presence of H, A, and B antigens on both RBCs and in Secretions

2. Controls presence of ABH antigen in the secretions

3. Inherit 1 gene from each parent that codes for an enzyme that adds a sugar to the H antigen

Genes at three separate loci control the occurrence and location of A and B antigens

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Genotype Antigens Blood type

AAA A

AO

BBB B

BO

AB A and B AB

OO None O

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BLOOD TYPING, TRANSFUSION, REACTIONS

Doc Jennyca De Villa

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ABO TYPING

2 Methods: Direct/Toward/Cell Grouping – Testing the patients red cell

using known antisera Anti-A : Blue Anti-B : Yellow

Indirect/Reverse/Serum Group – Testing the patients using known cells (To detect Antibodies)

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ABO SYSTEM IN BLOOD TRANSFUSIONType A have anti-B antibodies in their plasma, thus agglutinate type B or type AB blood.

Type B have anti-A antibodies and will agglutinate type A or type AB blood

Type AB blood has neither anti-A nor anti-B antibodies (universal recipient)

Type O blood has neither A nor B substances (universal donor)

Explanation of these findings is related to the fact that the body does not usually produce antibodies to its own constituents.

Thus, individuals of type A do not produce antibodies to their own blood group substance, A, but do possess antibodies to the foreign blood group substance, B, possibly because similar structures are present in microorganisms to which the body is exposed early in life.

Since individuals of type O have neither A nor B substances, they possess antibodies to both these foreign substances.

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RED BLOOD CELL COMPATIBILITY TABLE

Recipient[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.

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UNTOWARD EFFECTS OF BLOOD TRANSFUSION

Hemolytic Transfusion Reactions Anaphylaptic and Allergic Reactions Circulatory Overload Bacterial Reactions Miscellaneous Acute Problems Delayed Effects Transmission of Diseases

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HEMOLYTIC TRANSFUSION REACTIONS The most dreaded transfusion reaction Results from acute hemolysis of donor’s red cells as they

enter the circulation of the recipient Caused by ABO incompatibilty which most frequently

results from some form of clerical error Signs and Symptoms:

Fever Chills Flushing Nausea Burning at the intravenous (IV) line site Chest tightness Restlessness Apprehension Joint pain Back pain

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ANAPHYLACTIC AND ALLERGIC REACTIONS Happens very rapidly as the transfusion

begins Requires immediate intervention Cause by a rapid antibody reaction to a

plasma protein lacking the recipient Signs and Symptoms:

Urticaria or Hives

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CIRCULATORY OVERLOAD Sudden increase in circulating blood volume

are not well tolerated by patients with: Cardiac / Pulmonary diseases Very anemic patients Infants

Signs and Symptoms: Dyspnea Coughing Pulmonary Edema Cyanosis

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BACTERIAL REACTIONS When the donor’s blood is contaminated with

large numbers of living organisms Often caused by psychrophilic organisms Signs and Symptoms:

Chills Headache Vomiting Muscle pains Diarrhea High Fever

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MISC ACUTE PROBLEMS Citrate Intoxication Hyperkalemia Hypothermia Pulmonary insfuciency due to debris in stored

blood Air embolism Hemolysis due to overheated blood

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DELAYED EFFECTS Delayed hemolytic reactions

5-7 DaysReason: A previously immunized recipient may

have little or no circulating antibody at the time compatibility tests are performed.

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TRANSMISSION OF DISEASES (UNLUCKY ONES) Viral Hepatitis

Cytomegalovirus Infection

Syphilis

Malaria

AIDS

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GUIDE QUESTIONS

What are the compositions of RBC? Discuss the Biochemical Basis of blood typing and blood type

determination. Explain the importance of the oligosaccharide sequence in the

RBC membrane in blood type determination. Explain the role of genetics in determining the blood type,

especially in the oligosaccharide content of membrane lipoproteins.

Discuss the biochemical basis of ABO incompatibility.

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