Abbas Ahmed Abbas Shawka

“ ABO “ & “ Rh “ Blood Typing Systems

Mismatch blood transfusion lead to immune reaction between “ agglutinogens “ on the surface of RBCs of donor and “ agglutinins “ in the plasma of recipient. There is two Major types of these systems which are :

ABO blood typing system Rh system

Why we study these systems ?

Although there is other “ antigens “ in the blood but we usually do NOT study it because most of them are WEEK

ABO Blood Typing System

TWO major types of antigens 1- A2-B Antibodies corresponds to these antigens

A person that carries the ( A ) agglutinogens also carries antigens for ( B ) agglutinogens and referred to as ( A ) blood type.

A person that carries the ( B ) agglutinogens also carries antigens for ( A ) agglutinogens and referred to as ( B ) blood type.

A person that carries both ( A ) & ( B ) agglu-tinogens does Not carry antigen for neither ( A ) or ( B ) agglutinogens and referred to as ( AB ) blood type.

A person that does Not carries neither ( A ) agglutinogens or ( B ) agglutinogens , carries both antigens for ( A ) & ( B ) agglutinogens and referred to as ( O ) blood type.

Questions ?

1- People with ( O ) blood type can donate blood for all other blood type including ( O ) ?

2- People with ( AB ) blood type can receive blood from all other types including ( AB ) ?

Titer of agglutinins differ by different Ages.

AGGLUTINATION PROCESS IN TRANSFUSION REACTIONS

Because the agglutinins have 2 binding sites (IgG type) or 10 binding sites (IgM type), a single ag-glutinin can attach to two or more RBCs at the same time, thereby causing the cells to be bound together by the agglutinin. This bind-ing causes the cells to clump, which is the process of “agglutination.” Then these clumps plug small blood vessels throughout the circulatory system

Immediate VS. Delayed

Immediate intravascular hemolysis is far less common than agglutination followed by delayed hemolysis, because not only does there have to be a high titer of antibodies for lysis to occur, but also a different type of antibody seems to be required, mainly the IgM antibodies;theseantibodies are called hemolysins.

Question ?

When we have blood transplant from ( O ) person to ( A ) or ( B ) person, Why there will not be any reaction between antigens of ( O ) person with agglutino-gens of both ( A ) & ( B ) ?

Explain ?

Question ?

In mismatched blood transfusion why the person will develop “jaundice” ?

Rh system What is the different between ABO system & Rh sys-tem ?

In the O-A-B system, the plasma agglutinins re-sponsible for causing transfusion reactions develop spontaneously

whereas in the Rh system, spontaneous agglu-tinins almost never occur. Instead, the person must first be massively exposed to an Rh antigen, such as by transfusion of blood containing the Rh antigen, before enough agglutinins to cause a significant transfusion reaction will de-velop.

Rh antigensC D* Ec d e

A person with antigen C don’t have antigen c , also a person that will no have antigen c will have antigen C and it is correct for other antigens.

*D antigen “ Rh factor “ is the most antigenic antigen, people have D antigen referred to as “ Positive Rh “ and people do not have antigen D referred to as “ Negative Rh “.

If a negative Rh factor person 1- get positive Rh factor blood transfusion, that will cause no immediate reaction and this person will convert to immunized positive Rh factor and hemolysis do not occur ( delayed ) Because cells with antibodies will be phagocytic by macrophage.

2- get positive Rh factor blood transfusion again, immediate reaction occurs because the body have immunized against Rh factor and this will lead to severe hemolysis.

Erythroblastosis Fetalis (“Hemolytic Disease of the Newborn”)

When the mother is negtive Rh factor and the father is posi-tive Rh factor

Fetus will inherit positive Rh factor from his father. Mother will develop antibodies against Rh factor from expo-

sure to fetal+ve Rh factor Mother antibodies against +ve Rh factor ( agglutinins ) will

difuse through the placenta and will cause hemolysis for fe-tus blood.

The anti-D antibody is also administered to Rh-negative women who deliver Rh-positive babies to prevent sensitiza-tion of the mothers to the D antigen.