Blood Grouping New

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DR. AQUIL AHMDDept. of physiology

JNMC. AMU. Aligarh.


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History of Blood Groups and Blood Transfusions

Experiments with blood transfusionshave been carried out for hundreds ofyears. Many patients have died and it wasnot until 1901, when the Austrian Karl

Landsteiner discovered human bloodgroups, that blood transfusions becamesafer.

He found that mixing blood from two

individuals can lead to blood clumping.The clumped RBCs can crack and causetoxic reactions. This can be fatal.


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Karl Landsteiner discovered that bloodclumping was an immunological reactionwhich occurs when the receiver of a bloodtransfusion has antibodies against the donor

blood cells.

Karl Landsteiner's work made it possible todetermine blood types.

For this discovery he was awarded theNobel Prize in Physiology in 1930.

History of Blood Groups and BloodTransfusions (Cont.)


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The differences in human blood are due to the

presence or absence of certain protein moleculescalled antigens and antibodies.

The antigens are located on the surface of the

RBCs and the antibodies are in the bloodplasma.

Individuals have different types andcombinations of these molecules.

The blood group you belong to depends onwhat you have inherited from your parents.

What are the different blood groups?


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BLOOD GROUP SYSTEM A group of relatedantigens present on RBC that show similarchemical genetic and reactivity properties.

There are more than 20 genetically determinedblood group systems known today. eg. ABO, Rh,MNS, Lutheran Kell, Coltan,Duffy.

The AB0 and Rhesus (Rh) systems are themost important ones used for blood transfusions.

What are the different blood groups?


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According to the ABO bloodtyping system there are four

different kinds of blood types:A, B, AB or O (null).

ABO blood grouping system


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The ABO Antigens They are complex oligosaccharides present over RBC surface.

Basic Substrate Molecule is H (fucose) antigen.

A antigen - N-acetyl-galactosamine

B antigen - Galactose

A and B genes code for transferase enzymes


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Blood group AIf you belong to the blood

group A, you have Aantigens on the surface ofyour RBCs and Bantibodies in your bloodplasma.

Blood group BIf you belong to the bloodgroup B, you have Bantigens on the surface ofyour RBCs and Aantibodies in your bloodplasma.

AB0 blood grouping system


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Blood group AB

If you belong to the blood groupAB, you have both A and Bantigens on the surface of yourRBCs and no A or B antibodiesat all in your blood plasma.

Blood group OIf you belong to the blood group O

(null), you have neither A or Bantigens on the surface of your RBCsbut you have both A and B antibodiesin your blood plasma.


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ABO Antibodies Produced after first few months of life reaching

maximum by the age of 10 years.

They are produced to non-self antigen.

ABO antibodies are mainly IgM type.

They are cold antibodies as the react best at lowtemp. 0f 5*-20*


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Antigens are present from time birth but not theantibodies.The "A and "B" antigens are also producedby some other plants and microorganisms.

These antigens are absorbed into blood andstimulate the formation of antibodies aganistantigen not present in the infant red cell.

Why do individuals produce antibodies to

antigens they do not have?


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LANDSTEINER LAWThis has two component.

1) if an antigen is present on RBC of an individual,the corresponding antibody must be absent inplasma.

2) if an antigen is absent in RBC, the correspondingantibody must be present in the plasma.


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The ABO gene is autosomal (the gene is not on either sex

chromosomes)

The ABO gene locusis located on the chromosome 9.

Each person has two copies of genes coding for their ABO blood

group (one maternal and one paternal in origin)

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

A and B group genesare co-dominant

ABO inheritance and genetics


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Rh antigens are transmembrane proteins with loops

exposed at the surface of red blood cells.

They are of several types eg C, D, E but D is mostpotent.

They are named for the rhesus monkey in which theywere first discovered in 1940 by Landsteiner and weiner.

RBCs that are "Rh positive" express the antigen

A person with Rh- blood does not have Rh antibodiesnaturally in the blood plasma

The Rhesus (Rh) System


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Distribution of Rh(D) Types

Population Rh(D) pos Rh(D) neg

Caucasian 86% 14%

African-American

95% 5%

Oriental >99%


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A person with Rh- blood can develop Rh antibodiesin the blood plasma if he or she receives blood from aperson with Rh+ blood, whose Rh antigens can trigger

the production of Rh antibodies.

A person with Rh+ blood can receive blood froma person with Rh- blood without any problems.


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People with blood group Oare called "universal

donors" and people withblood group AB are called"universal receivers."

Blood transfusions who canreceive blood from

whom?


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BloodGroup

Antigens Antibodies Can giveblood to

Canreceive

blood from

AB A and B None AB AB, A, B, O

A A B A and AB A and O

B B A B and AB B and O

O None A and B AB, A, B, O O


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Significance of ABO Group

1) Bloodtransfusion fortreatment

purposes.

CROSS MATCHING

MAJOR CROSSMATCHING

MINOR CROSSMATCHING


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2) PATERNITY DISPUTES.

3) MEDICOLEGAL USE.

4) SUSCEPTIBILITY TO DISEASE.


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Significance of Rh(D) 80% of Rh(D) neg persons exposed to Rh(D) pos blood will

develop anti-D.

Anti-D can also be stimulated by pregnancy with an Rh(D)positive baby in Rh(D) neg mother.

Sensitisation can be prevented by the use of anti-Dimmunoglobulin, antenatally and postnatally.

Rh(D) neg females of childbearing potential should neverbe given Rh(D) positive blood products


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