Blood Groups & Blood Transfusion - PowerPoint Presentation

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Blood Groups & Blood Transfusion

Dr. Shaikh Mujeeb AhmedAssistant ProfessorAlMaarefa College

HMIM BLOCK 224

Objectives

Different types of Blood groups blood group systemExplain blood typing and how it is used to avoid adverse reactions following blood transfusions. Describe how blood reactions may occur between fetal and maternal tissues.

Blood Groups and Transfusions

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In the year 1900, identification of the ABO blood antigen gene explained the observed blood type

incompatibilities by

Karl Landsteiner

Today there are 31 different genes known to contribute to the surface features of RBCs determining compatibility between blood types

Blood Group Systems

Major systemsABORhesus system(Rh)MinorMNPFamilial blood groups

Importance of Blood Groups

Transfusion of bloodAssociation with diseaseDuodenal ulcers are more common in group O than in A or BTumors of salivary glands, stomach and pancreas are more common in group A than in group O individuals.

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Antigens and Antibodies

Terms to become familiar with:

Agglutination – clumping of red blood cells in response to a reaction between an antibody and an antigen

Antigens – a chemical that stimulates cells to produce antibodies

Antibodies – a protein that reacts against a specific antigen

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Type B blood

Type AB blood

Type O blood

Red blood cell

Red blood cell

Anti-B antibody

Antigen A

Anti-A antibody

Anti-B antibody

Red blood cell

Antigen A

Antigen B

Red blood cell

Anti-A antibody

Antigen B

Type A blood

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Red blood cell

Anti-B antibody

(a)

(c)

(d)

(b)

Agglutinated red

blood cells

Anti-A antibody

Antigen A

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ABO Blood Group

Based on the presence or absence of two major antigens on red blood cell membranes

Antigen A

Antigen B

Antigens and antibodies of the ABO blood group

Blood TypeAntigenAntibodyAA

Anti B

B

B

Anti A

AB

A and B

Neither Anti

A nor Anti B

O

Neither

A nor B

Both Anti A and Anti B

Genotype of ABO blood groups

Blood GroupPossible Genotype(s)AAA, AOB

BB, BO

AB

AB

O

OO

Landsteiner’s law.

If an agglutinogen (antigen) is present on the RBCs the corresponding agglutinin (anti body) must be absent in the plasmaIf an agglutinogen (antigen) is absent on the RBCs the corresponding agglutinin (anti body) must be present in the plasmaThe first law is applicable to all blood groups. But the second part is not necessary always, its true for ABO blood groups.

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Rh Blood Group

The

Rh

blood group was named for the rhesus monkey

The group includes several Rh antigens or

factors (Cc,

Dd

&

Ee

)

Rh

positive – presence of antigen D or other

Rh

antigens on the red blood cell membranes

Rh

negative – lack of these antigens

The seriousness of the

Rh

blood group is evident in a fetus that develops the condition

erythroblastosis

fetalis or hemolytic disease of the newborn

Erythroblstosis

Fetalis14

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Rh-negative

woman with

Rh-positive

fetus

Cells from

Rh-positive

fetus enter

woman’s

bloodstream

In the next

Rh-positive

pregnancy,

maternal

antibodies

attack fetal red

blood cells

Woman

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sensitized—

antibodies (

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form to fight

Rh-positive

blood cells

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Erythroblastosis Fetalis

(Hemolytic disease of the newborn-HDN)Clinical FeaturesEdema (Hydrops)JaundiceAnemiaEnlarged Liver & Spleen

Erythroblastosis Fetalis

(Hemolytic disease of the newborn-HDN)Treatment Exchange blood transfusionPreventionRh immune globulin (RhIG) injections to the Rh –negative mother during pregnancy

Blood groups in local population

Blood GroupPercentage of PopulationO +48 %

A +

24 %

B +

17 %

AB +

4 %

Rh Positive are about 93% (90-95%)

O-

4 %

A-

2%

B-

1 %

AB-

0.23%

Rh negative are about 7% (5-10%)

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Blood transfusion

Autologus

blood transfusion

Blood grouping and cross matching

Donor’s RBCs + Recipient’s plasma (major cross matching)

Recipients RBCs + Donor’s plasma (minor cross matching)

Proffered And Permissible Blood Types For Transfusion

Blood Type of RecipientPreferred Blood Type of The DonorPermissible Blood Type of The Donor (In Extreme Emergency)

A

A

O

B

B

O

AB

A B

A,B, O

O

O

No alternate type

Complications of Blood Transfusion

Fatal hemolytic reactions in mismatched reactions. Rapid hemolysisJaundiceRenal tubular damage Circulatory overload – if rapid transfusionHemosiderosis – repeated blood transfusionElectrolyte disturbancesTransmission of diseaseHepatitis – B or CAIDS