Erythroblastosis Fetalis: Hemolytic disease of the newborn

 

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Mismatching of the mother's blood group with her fetus can cause brain damage to the fetus

Erythroblastosis Fetalis: Hemolytic disease of the newborn

Hypersensitivity ! when intolerance undesirable reaction produced by the normal immune system is known as hypersensitivity. Depending upon the immunologic aspects hypersensitivity reaction can be categorized into 4types .ie. Hypersensitivity type I, II, III, and IV. When our body shows hypersensitivity then it may cause various types of damages. Anaphylaxis, allergic rhinoconjunctivitis, etc are examples of hypersensitivity. 

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Transfusion reaction of mismatching blood group

Our blood group containing RBCs .ie. Red Blood Cells are encoded by different genes. Each of which has several alternative alleles. An individual possessing one allelic form of a blood group an antigen can recognize other allelic forms on transfused blood as foreign and mount an antibody response. 

Here is an example of a transfusion reaction. If in a case individuals have a type A blood group is transfused with the individual that have a blood containing type B cells, then during transfusion of blood the anti-B isohemagglutinins binds to the type B blood cells and mediate the destruction via complement-mediated lysis this type of reaction between the two different blood group transfusion is called a transfusion reaction. 

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Erythroblastosis Fetalis: Hemolytic disease of the newborn

The hemolytic disease is shown in newborns. Other names of Erythroblastosis Fetalis disease are Hemolytic disease of the fetus and newborn (HDFN) and alloimmune HDFN. This disease basically occurs when maternal immunoglobulin antigen ( IgG) antibodies that are specific for fetal blood-group antigen cross the placenta ( Where fetal placed in mother womb) and destroy fetal red blood cells then it leads to erythroblastosis fetalis in newborn. The consequences of this hemolytic disease can be minor, serious, or lethal.

 In the majority of cases around 65% of hemolytic disease of the newborn have minor consequences that are caused by ABO-group incompatibility between mother and fetus.

How Erythroblastosis fetalis develop in the fetus?

Erythroblastosis fetalis most commonly develops when an Rh+( Rhesus positive ) fetus expresses an Rh antigen on its blood cells that the Rh- ( Rhesus negative)and then the mother does not express.

During pregnancy, mother blood circulation is separated from fetus blood circulation via a layer of cells in the placenta known as the trophoblast. This layer prevents to mixing of blood circulation of both mother and fetus during the pregnancy period. 

At the time of delivery, the placenta allows a larger amount of fetal umbilical cord blood( Umbilical cord-Connecting tube between mother and fetus during pregnancy)to the mother’s blood circulation. 

During this blood- exchange transfusion reaction fetal red blood cells activate Rh-specific B cells that result in the production of Rh-specific plasma cells and memory cells in the mother. Activation of these memory cells in the subsequent pregnancy results in the formation of Immunoglobulin G (IgG) anti-Rh antibodies which cross the placenta and damage the fetal red blood cells.

How Rh-incompatibility can be detected?

The Rh-incompatibility can be detected by a test name is the Coombs test. 

What is the Coombs Test?

The coombs test helps to detect the Rh-incompatibility vis detecting antibodies that act against the surface of Red blood cells.

The presence of maternal IgG on the surface of fetal red blood cells can be detected by this test. There is a coombs reagent that helps in the detection of Rh-incompatibility.

During the coombs test, isolated fetal red blood cells are incubated with coombs reagent, if maternal IgG is bound to the fetal red blood cells if the cells agglutinate with the coombs reagent that shows the presence of Rh -incompatibility.

How to prevent it?

Erythroblastosis fetalis disease is caused by Rh-incompatibility so, this can be prevented by administering antibodies against the Rh antigen to the mother. These administering antibodies are marked as Rhogam.

Administering of anti-Rh-antibodies to the mother should be :

1. Around the 28 weeks of pregnancy 
2. During 24 to 48 hours after the first delivery. 
3. can be administered this anti-Rh-antibodies to pregnant women after amniocentesis. 

During administering of anti-Rh-antibodies bind to fetal red blood cells then it entered to mother's blood circulation and further helps to facilitate their clearance before B-cell activation and the ensuing memory B-cell production can take place. 

With the help of this Rhogam treatment, the fetus can be protected from Erthyroblastosis Fetalis disease.

References :

George N. Nassar and Cristin Wehbe (2020), “ Erthyloblastosis Fetalis”.. Treasure Island (FL): StatPearls Publishing; 2020 Jan.PMID: 30020664.Bookshelf ID: NBK513292

https://www.healthline.com/health/erythroblastosis-fetalis#diagnosis

https://www.medicalnewstoday.com/articles/314472

www.ncbi.nlm.nih.gov

Image References :

https://cdn.pixabay.com/photo/2019/10/09/03/31/ultrasound-4536369_960_720.jpg

https://cdn.pixabay.com/photo/2019/03/07/09/04/blood-4039751_960_720.jpg