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7/30/2019 Blood Banking 1

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Genetics

Population Genetics-Mendels Laws of Inheritance

-Hardy-Weinberg Principle

-Inheritance Patterns

Cellular Genetics- Genetics &CytologyCell Division

-Mitosis

-Meiosis

Molecular Genetics

-Deoxyribonucleic Acid (DNA)

-Ribonucleic Acid (RNA)


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RBC BIOLOGY

Structure and chemical composition, Hemoglobin, and Metabolism

I. Normal structure and composition of RBCA.Chemical Composition

RBC membrane External- glucose&choline phospho.

-Phospholipid

Internal- aminophospho.

Integral- Glycophorins

-Protein

Peripheral- Spectrin

B. Characteristic of RBC

Deformability

- Due to decrease of ATP and phosphorylation of spectrum.

Permeability

- freely permeable to water and anion.


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C. Metabolic Pathways Mainly anaerobic energy (90% ATP)

Other Pathways :

Pentose Phosphate - (10% ATP)

Methemoglobin Reductase - Prevents conversion of ferrous to ferric.

Luebering Rafofort2,3 PDG affinity of hemoglobin to Oxygen.

Tensed

Relaxed


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II. Hemoglobin Structure and Function

A. Hemoglobin SynthesisTypes of Hemoglobin : Adult

- alpha

- beta

B. Hemoglobin Functiongas transportaion


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GENETICS OF ABO BLOOD GROUP

Blood groups A or B are either HOMOZYGOUS or HETEROZYGOUS

Blood group AB is always HETEROZYGOUS

Blood group O is always HOMOZYGOUS

INHERITANCE OF ABO BLOOD GROUPS

Blood Types of Couple (Parents) Possible Blood Types of Children

A & AB A, B, AB

B & AB A, B, AB

A & B A, B, AB, O

AB & O A, B

A & O A, O

B & O B, O


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Mendelian Law of Blood Group Inheritance

1. A person inherits one paternal and one maternal allele.

2. A person can either be homozygous or heterozygous for a blood group.

3. A blood factor can not be present in a child if the blood factor is absent to

both parents.4. A blood factor can not be absent in a child if one of his parents is

homozygous for a blood group.

Blood Types Frequency

O 45%

A 41%

B 10%

AB 4%


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Formation of ABH antigen

A and B genes depend on H geneHH

Hh

hh/Oh (Bombay type)

ABO genes - do not directly code for ABH Ag

- code for the production of glycosyl transferase that add sugar to a precursorsubstance converted by H gene to H substance.

H substance converts AB gene to AB antigen.

O gene no conversion takes place.

* ABH substance in saliva (Secretor & Non-Secretor)

Se geneABH antigen in secretion3 genes:

SeSe seseNon-Secretor

Sese Secretor


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BOMBAY PHENOTYPES

Cells do not have the ABH antigens

Cells fail to react with anti-A

Cells do not react with anti-H lectin (Dolichos biflorus)

Only blood from another Bombay individual will be compatible and will be

transfused to a Bombay recipient.

Differences between Bombay and Group O blood

Cells contain Serum contains

Bombay group ---------------- Anti-A1,Anti-B,Anti-H

Group O H substance Anti-A1, Anti-B

The H ag is detected using antisera prepared from plant lectin- Ulex europaeus

Reactivity of Anti H sera w/ ABO Blood groups

O A2 B A2B A1 A1B


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Weak expression of D antigenDu- weak form of D antigen

- give weak or neg. rxn w/anti D

-detected only by IAT (indirect antiglobulin test)

3 mechanisms that explain weakened D ag

Genetic weak D

C trans

D mosaic or partial


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Subgroups of A and B

Weak A subgroups

A3, Ax, Aend

Am, Ay, Ael

Weak B subgroups

B, B3

, Bx

Bm, Bel


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Fisher-Race concept of Rh

D

Production

Close C/ c

Linkage

Pathway E/ e

RBC Surface

D Gene

C/c Gene

E/e Gene


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Weiners Agglutinogen Theory

Rh0

Rh gene hr'

hr"

RBC Surface

Factor Rh0

Factor hr'

Factor h"

Aggutinogen Rh Factor


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Rosenfield

- a number is assigned to each antigen of the Rh system in order of its discovery

example : ( Rh1 = D, Rh2 = C, Rh3 = E, Rh4 = c, Rh5 = e)

ISBT ( International Society of Blood Tranfusion)- to establish a uniform nomenclature that is both eye- and machine-readable and is inkeeping with the genetics basis of blood groups.

example : Rh1004001

Rh2004002

Rh3004003

Rh4004004

Rh5004005


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Rh Blood Group System

FISHER RACE WIENER

Gene complex Antigens Shorthand

Designation

Gene Agglutinogen Blood Factors

Dce D, c, e Ro Rho Rho Rho, hr hr

DCe D, C, e R1

Rh1 Rh1

Rho, rh hr

DcE D, c, E R2 Rh2 Rh2 Rho hr rh

DCE D, C, E Rz Rhz Rhz Rho rh rh

dce c, e r rh rh hr hr

dCe C, e r rh rh rh hr

dcE c, E r rh rh hr rh

dCE C, E ry rhy rhy rh rh


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MINOR BLOOD GROUP

SYSTEM

The Lewis System and Secretor Status

1.Inheritance

a. the Lewis antigen is inherited by means of

2 genes : Le, lei. the Lewis Positive (Le) gene converts a

precursor material to Lea substance.

ii. The Lewis negative (le) gene cannot convert a

precursor material to Lea substance.


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2. The expression of Lewis antigens is influenced by the

presence of Hh and Sese genes.

i. Se gene determines secretor status.

ii. H gene produces the ability to secrete

H antigen

When both are present they convert Lea to Leb subst.

Lewis phenotypes

Le(a-b+)-present in secretors. Have Lea&Leb in secretions

Le(a+b-)-present in non-secretors. Have Lea in secretionsLe(a-b-)- usu. Fd. in secretors. Never secrete Lea&Leb subst


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P Blood Group SystemAntigens

1.P antigen universal ag on red cells, white tissue cells andplasma, most common deteriorate rapidly.

2.The P1 antigen is present on the red cells of 79% of the

population

3.Individuals who lack P1 are termed P2.

4. Individuals who lack P1 P1 or P k antigens are termed p


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I, i BLOOD GROUP SYSTEM

1.I, i antigensa.a. I is a public antigen i.e. most adults posess the I

antigen. I antigen is found on cord blood cells.

b. b. it is transitional between I and i.

2.Antii.

3.a. a. Common abs seen association withmycoplasma pneumonia and cold AHA


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MNSsU BLOOD GROUP SYSTEM

This was discovered in 1927 by Landsteiner and Levine.

Consists of 40 ags of w/c only 4 are commonly encountered.

Biochemistry of MNSs Antigens

-Encoded by genes on chro.4

-Developed at birth

-MN ags reside on Glycophorin A-Ss&U ags reside on Glycophorin B

Plant lectins that exhibit Anti M reactivity:

Iberis amara, I.umbellate

Japanese turnip

Plant lectins that exhibit Anti N reactivity:

Bauhinia variegata, B.candicans

Vicia graminea


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The Kell and Kx Blood Group System

Antigens:

K and k antigens:

a. K- excluding ABO, K is the second only to D in

immunogenecity.

b. k- antibodies to k antigen are seldom encountered.

Antibodies:

Anti-Kis the most common antibody seen in the blood bank,

it isusually IgG and reactive in the antiglobulin phase.


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ANTIGLOBULIN (COOMBS TEST)

-AHG binds to IgG bound to red cell or free in the serum

-Used to detect red cells sensitized by IgG alloantibodies ,IgG autoantibodies,

and/or complement components

DIRECT INDIRECT

Principle Detects in-vivo RBC

sensitization

Detects in-vitro

sensitization

Applications HDN.

HTR

AIHA

Drug-induced sensitization

Antibody detection

Antibody identification

Antibody titration Red cellphenotype (Du, K, Fy)


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Causes of False (+) AHG Test

Extreme reticulocytosis

Lead poisoning

Certain viral disease

Refrigerated clotted specimen may cause in vitro complement attachment

Autoagglutinable (polyagglutinable) cells

Bacterial contamination of cells or saline used in washing

Dirty glasswares

Causes of False (-) AHG test

Failure to add AHG reagent

Undercentrifugation

Inadequate or improper washing of cells

Nonreactive AHG reagent

Cell suspension either too weak or too heavy


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Detection and Identification of Antibodies

I.Antibody screen IV. DAT and Elution Technique

-Tube Technique -Temperature

-Gel Technique -pH-Solid Phase Technique -Organic Solvents

-Interpretation

-Limitations

II. Antibody Identification V. Antibody Titration

-Patient History

-Reagents

-Exclusion

-Evaluation of Panel Results

III. Antibody Identification

-Selected Cell Panels

-Enzymes

-Neutralization

-Adsorption


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ANTIBODY SCREENING TEST

Antibody screening is based on indirect AHG or AHG test. Reagent O-

cells are subjected to all phases of cross-matching. Presence of unexpectedantibody will recognized by the haemagglutination reaction or haemolysis of O-

cells. This usually occurs in thermophase (with protein) and AHG phase .the

nature of the antibody is judged by the reaction phase. If agglutination of red cells

does not occur, it it concluded that the patients serum does not have unexpected

antibodies.

IDENTIFICATION OF IRREGULAR ANTIBODIES

If the presence of irregular antibody is detected in the antibody procedure

described earlier, the specificity of the antibody should be determined. Because of

the lack of availability of panel reagent cells with known antigenic character, it is

difficult to identify the antibody in a routine blood bank laboratory of a developing

country.


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TYPE OF BLOOD DONOR

I.Autologous Donors - one who donates blood for his or her own use, referred to as the donor-patient. Autologous blood is safer than allogeic blood.

Types:

1. Preoperative collection

2. Acute normovolemic collection

3. Intraoperative collection

4. Postoperative collection

II.Directed Donor - is a unit collected under the same requirements as those for allogeneic donors,except that the unit collected is directed toward a specific patient.

III. PheresisA pheresis donor may be characterized into one or all of the following:

1.Plateletpheresis

2.Plasmapheresis

3.Leukopheresis

4.Double RBC pheresis

5.Stem cell pheresis


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DONOR SCREENING

I.Registration

- Obtaining an accurate medical history of the donor is essential to ensure benefit to the

recipient.

- Name (first, last, MI) - Gender

- Date and time of donation - Age or date of birth

- Address - Consent to donate

- Telephone

II.Medical History Questionnaire

III. The Physical Examination

-General Appearance -Weight

-Temperature -Pulse

-Blood Pressure -Hemoglobin

-Skin Lesions

IV. Informed Concent

- the donor must be informed of the risks of the procedure.


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ABO Blood Group System

1. Antigen inheritance

-in a codominant manner following simple Mendelian genetics laws. Other

genetic loci interact with the ABO locus:

H, Se, Le, I, and P

-is controlled by the A, B, and H genes

2. Antigen Developmenta. H antigens are precursor for the A and b antigens. The presence of H

substances in the body secretions is controlled by the Se gene.

* individuals who are homozygous (SeSe) or heterozygous (Sese) are called

secretors.

Group O secretors- have H antigen

Group A secretors- have A and H antigens

Group B secretors- have B and H antigens

Group AB secretors- have A, B and H antigens


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b. A and B antigens

c. O gene does not result in the conversion of H antigen

3. Phenotypes

- ABO genes allow for five different phenotypes:

a.) A phenotype. Group A individuals may be homozygous (AA) or

heterozygous (AO)

b.) B phenotype. Group B individuals may be homozygous (BB) or

heterozygous (BO)

c.) AB phenotype. Group AB individuals have both A and B antigens on their

RBCs, but lack both anti-A and anti- B antibodies in their serum or plasma.

d.) O phenotype. Group O individuals are homozygous (OO) and have neither

A nor B antigens on their RBCs

e.) Bombay phenotype.

4. ABO antibodies

a. naturally occuring antibodies- mostly IgM; best at room temperature or below

b. immune ABO antibodies are usually IgG and can cross the placental barrier


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5. Testing

a. Forward Grouping

b. Reverse Groupingc. Discrepancies:

Subgroups of A or B

Polyagglutination

Interfering substances in the serum or plasma

IgM alloantibodies

Strong autoantibodies

Rouleaux

The age of the patient

Disease


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Rh Blood Group System

1. Nomenclature

Fisher- Race- D, C, E, c and e

WienerRho, rh, rh, hr and hr

Rosenfield- Rh1, Rh2, Rh3, Rh4 and Rh5

International Society of Blood Transfusion (ISBT)

2. D antigen

- only Rh antigen that undergoes routine testing\

-Incomplete D antigens result when some of the component parts are missing,individuals with

these antigens are called D mosaics.

-Du is a weakened form of D antigen

3. C and c antigens are codominant. Less immunogenic than D antigens

4. E and e antigen expression is codominant- as immunogenis as D antigens

5. G antigens

6. Compound antigens- occur when two Rh genes are on the same chromosome

Ex. f(ce), rhj (Ce), cE, CE, V (ces)


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7. D- deletion genes

8. Rh null

9. LW antigens

10. Rh- system antibodies

-most are IgG1 and IgG3

-do not agglutinate in saline

-react best at 37 o C

-enhanced by enzyme-treated RBCs

-do not usually bind complement

-often occur together

-cross the placenta and can cause HDN

11. Rh- antigen- detection reagents

a) High protein IgG anti- D reagents

b) IgM anti-D reagents

c) Chemically modified IgG anti-D reagents

d) Monoclonal anti- D reagents


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Routine Blood Bank Testing: Comparison of

Traditional and Alternative method

Traditional Gel Solid-Phase

Reaction

Chamber

Tube Microtube Card Microplate wells

Reaction

pattern

Agglutination Agglutination Solid-phase

immune

adherence

Reaction

Matrix

None

(Cell andSerum/Plasma)

Immunologically

inert dextran-acrylamide gels

Chemically

modifiedpolystyrene

microplate wells


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Testing

Detection

AHG

(Antihuman

Globulin Sera)

AHG

(Antihuman

Globulin Sera)

Anti- IgG-

coated red cells

Washing

Required

YES NO YES

Raction

readings

Quantitative

1+ to 4+, MF

Quantitative

1+ to 4+, MF

Semiquantitative

Strong pos, Pos,Neg, No MF

Stable

Reaction

No Yes (2-3 days) Yes (2 days)


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Specialequipment No Yes Yes

Automation

(FDA-

approved)

No Yes Yes


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Comparison of PCH and CHD

PCH CHD

Patient Population Children and young Elderly or middle aged

adults

Pathogenesis following viral infection Idiopathic,

Lymphoproliferative

disorder: following M.

pneumoniae infectionClinical features Hemoglobinuria, Acute

attacks upon exposure to

cold (symptoms resolve in

hours to days)

Acrocyanosis;

Autoagglutination of blood

at room temperature

Severity of hemolysis Acute and rapid Chronic and rarely severe

Site of hemolysis Intravascular Extravascular/ Intravascular

Autoantibody class IgG (Anti-P specificity;

biphasic hemolysin)

IgM (Anti-I/I) monophasic


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DAT 2-3 + polyspecific AHG;

negative IgG

3-4 + monospecific C3

AHG

2-3 + polyspecific AHG;

negative

IgG; 3-4 + monospecific

C3 AHG

Thermal range Moderate(


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Blood Component Therapy

Component Indication for Use

Whole blood rapid blood loss

PackedRBC symptomatic anemia

DeglycerolizedRBC rare donor&autologous donation

WashedRBC avoid allergic rxn

Leuko.poorRBC for leuko.antibodies

FFP DIC,VitK deficiency


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Platelets Thrombocytopenia

Plasma volume expander

Cryopptate Hemophilia A,FactorXIII

Granulocyte Neutropenia,sepsis

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