BLOOD TRANSFUSION

DR DAMULAK O D

OUTLINE

• INTRODUCTION
• BLOOD GROUP ANTIGENS AND ANTIBODIES
• DONOR SELECTION
• BLOOD COLLECTION
• BLOOD TESTING
• TRANSFUSION
• ADVERSE EFFECTS OF TRANSFUSION
• INVESTIGATION OF AHTR AND MANAGEMENT
• PREVENTION OF AHTR

Blood Group Antigens

• ABO/ABH
• Rh (DCcEe
• Kell
• Duffy
• MNSs
• P
• Ii
• lewis

ANTIGENS

• substances that have the capability to stimulate the production of an antibody
• characteristics:

1. Chemical nature – protein, CHO, lipopolysaccharide or nucleic acid

2. Molecular weight > 10,000 daltons

3. Complexity – more complex, > antibody stimulation

4. Stability – if unstable 🡪 degrade 🡪 less Ab stimulation

5. Foreign

IMMUNOLOGIC PRINCIPLES

IMMUNOLOGIC PRINCIPLES

Chemical composition of antigens:

1. Glycoproteins & lipoproteins – most potent
2. Glycolipids
3. Pure polysaccharides – not immunogenic except in humans and mice
4. Pure lipids & nucleic acids – not immunogenic but can be antigenic 🡪 serve as haptens

ANTIBODIES

• also called immunoglobulins
• characteristics:

1. Protein

2. Produced in response to stimulation by an antigen

3. Specific for the stimulating antigen

• consists of 2 heavy chains & 2 light chains held together by disulfide bonds
• produce 3 fragments when cleaved by enzymes 🡪 2 Ag-binding fragments (Fab) & 1 crystallizable fragment (Fc)

IMMUNOLOGIC PRINCIPLES

Classification of Blood Group Antibodies:

1. Alloantibodies
• Reacts with foreign Ag not present on patient’s own RBC
• Most produced as result of immune stimulation via transfusion or pregnancy (usually during delivery)
2. Autoantibodies
• Reacts with an Ag on patient’s own cells & with that same Ag on the cells of other individuals

IMMUNOLOGIC PRINCIPLES

IMMUNOLOGIC PRINCIPLES

Immunogenicity of Blood Group Antigens

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A, B and D (Rho) – most immunogenic

Kell (K)

Duffy: Fy^a

Fy^b

Kidd: Jk^a

Jk^b

• discovered by Karl Landsteiner; locus on chr 9
• single most important blood group for the selection and transfusion of blood
• widely expressed 🡪 tissues & body fluids including red cells, platelets & endothelial cells
• three antigens: A, B, H
• two major antibodies: anti-A and anti-B
• four phenotypes: A, B, AB, O 🡪 A & B Ag’s autosomal co-dominant (expressed on grp A, B and AB red cells; O phenotype autosomal recessive (most frequent)

ABO BLOOD GROUP SYSTEM

ABO Antigens

• present on the surface of red cells as well as tissue and endothelial cells in the body
• found in soluble form in plasma & other body secretions in people known as secretors
• inherited in simple Mendelian fashion from an individual’s parents
• 3 possible genes that can be inherited: A, B, O
• A and B genes produce a detectable product
• O gene does not produce a detectable product

ABO BLOOD GROUP SYSTEM

ABO BLOOD GROUP SYSTEM

• A and B genes do not directly produce antigens 🡪 produce an enzyme called transferase 🡪 attaches a sugar molecule to the chemical structure of the antigen 🡪 sugar molecule responsible for specificity

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• O antigen 🡪 no transferase 🡪 no antigen produced

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• A and B antigens on surface of RBC 🡪 protrude from outermost layer of cell membrane

ABO Basics

• Blood group antigens are actually sugars attached to the red blood cell.
• Antigens are “built” onto the red cell.
• Individuals inherit a gene which codes for specific sugar(s) to be added to the red cell.
• The type of sugar added determines the blood group.

This diagram illustrates the terminal sugar for each blood group.

ABO BLOOD GROUP SYSTEM

ABO BLOOD GROUP SYSTEM

ABO BLOOD GROUP SYSTEM

H Antigen

• required to produce either A or B antigens
• possible genetic combinations: HH, Hh, or hh
• HH or Hh (+) 🡪 produce H Ag 🡪 99.99% of Caucasians
• hh 🡪 does not produce H Ag 🡪 Bombay phenotype (Oh)
• anti-H antibodies rare – found only in individuals with Bombay phenotype

ABO BLOOD GROUP SYSTEM

ABO BLOOD GROUP SYSTEM

Group O

• Approximately 50% of the population is group O.
• No A or B antigens present, think of as “0” antigens present.
• These individuals form potent anti-A and anti-B antibodies which circulate in the blood plasma at all times.

Group A

• Approximately 26% of the population is group A.
• No B antigens present.
• These individuals form potent anti-B antibodies which circulate in the blood plasma at all times.

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Group B

• Approximately 21% of the population is group B.
• No A antigens present.
• These individuals form potent anti-A antibodies which circulate in the blood plasma at all times.

Group AB

• Approximately 4% of the population is group AB.
• Both A and B antigens present.
• These individuals possess no ABO antibodies.
• NOTE: This slide is in error as it only illustrates presence of one antigen not 2.

Hemolysis

• If an individual is transfused with an incompatible blood group destruction of the red blood cells will occur.
• This may result in the death of the recipient.

ABO BLOOD GROUP SYSTEM

Frequencies of ABO Blood Groups:

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Blood Group Frequency

O 50%

A 26%

B 21%

AB 4%

ABO BLOOD GROUP SYSTEM

ABO Subtypes:

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1. A variants (A₁, A₂)
• A₁ most common (80%) & most antigenic
• A₁ and A₂ differentiated using antisera specific for A₁ Ag (anti-A₁ lectin) prepared from seed known as Dolichos biflorus 🡪 (+) reaction with A₁ but not A₂
• Anti-A 🡪 reacts with both A₁ & A₂ but more strongly with A₂

ABO BLOOD GROUP SYSTEM

ABO Subtypes:

2. Weak A and weak B phenotypes
3. Null phenotypes:

(a) Bombay (Oh)

• No A, B or H Ag on red cells & secretions
• With anti-A, anti-B & anti-H in their sera

(b) para-Bombay

• Absent or only trace A,B & H Ag’s detected on rbc with normal expression in secretions & body fluids

ABO BLOOD GROUP SYSTEM

ABO Antibodies

• Natural antibodies 🡪 antigenic stimulus is environmental 🡪 exposure occurs from birth
• Newborns 🡪 without ABO antibodies of their own; begin to produce Ab with detectable titer at 6 months of age
• Other characteristics of ABO antibodies:
1. IgM
2. Reacts at room temp. after an immediate spin

ABO ROUTINE TESTING

(slide or test tube method)

DIRECT OR FORWARD TYPING

• test for antigens
• patient’s cells containing unknown antigens tested with known antisera
• antisera manufactured from human sera
• antisera used:

Antisera Color Source

Anti-A Blue Group B donor

Anti-B Yellow Group A donor

Anti-A,B Clear Group O donor

ABO ROUTINE TESTING

Anti-A,B

• not a mixture of anti-A and anti-B
• separate Ab that reacts with both A and B antigens
• used in forward grouping for two purposes:
1. confirms the results of the anti-A and anti-B
2. will show a (+) reaction with weak subgroups of A and B that do not react with the anti-A and anti-B

ABO ROUTINE TESTING

Reaction Patterns for ABO Groups

ABO ROUTINE TESTING

INDIRECT/REVERSE TYPING

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• known antigen (cell) vs. unknown antibody (patient’s serum)
• serum is combined with cells having known Ag content in a 2:1 ratio
• uses commercially prepared reagents containing saline-suspended A₁ and B cells

ABO / Anti A, B and AB

Rh BLOOD GROUP SYSTEM

• discovered in 1940 by Landsteiner & Wiener
• most complex erythrocyte antigen system; located on chromosome 1
• found exclusively on surface of rbc 🡪 integral part of red cell membrane
• primary antigen 🡪 if present, consider Rh (+)
• lack corresponding naturally-occurring antibodies in serum

Rh BLOOD GROUP SYSTEM

CLASSIFICATION/NOMENCLATURE SYSTEM

Wiener

• Multiple allele hypothesis
• 5 antigens: Rh_o, rh’, rh”, hr’, hr”
• Single locus inheritance system with 8 alternate common alleles coding for agglutinogens 🡪 1 individual produces 2 agglutinogens inherited from both parents

Rh BLOOD GROUP SYSTEM

CLASSIFICATION/NOMENCLATURE SYSTEM

Fischer & Race

• Three alleles: D/d, C/c and E/e
• Five antigens: D, C, E, c, e
• d 🡪 no D locus 🡪 no antigenic products

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BLOOD DONOR SELECTION

TYPES OF BLOOD DONOR

• VNRBD
• PAID
• FAMILY REPLACEMENT
• DIRECTED
• AUTOLOGOUS
• THERAPEUTIC

Medical history and personal data

• Personal data
• History of major illness
• History of major surgery
• Obstetric history
• History of scarification
• History of transplant
• History of travels
• Social history
• Documentation critical

Medical examinations

• General
• Systemic overview
• Haemoglobin determination
• Documentation critical

BLOOD COLLECTION

• Trained personnel
• Appropriate environment
• Good site identified
• Aseptic measures
• Apply band
• Collect into blood bag/Storage
• Quantity
• Documentation critical
• frequency

Adverse effects of blood donation

• Immediate Local Effects
• Delayed Local Effects
• Immediate Systemic Effects
• Delayed Systemic effects
• Remedies to adverse effects of blood donation

Cold Chain

• Blood deteriorates rapidly at room temperature
• Allow to stand at room temperature for not more than 2 hours
• Transfer to temperature control cooler or blood banks
• Ensure temperature is recorded regularly
• Maintain temperature till transfusion
• Complete transfusion within time

BLOOD TESTING

• Predonation
• Post donation

-grouping

-haemoglobin electrophoresis

-testing for TTIs

-cross matching

-documentation critical

Transfusion

• Attention at blood issuing

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• Attention at patient bed side

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• Documentation

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• Prepare to handle immediate HTR

• Attention at initial phase of transfusion

Conclusion