Question

2. What is the basis for the immune response that leads to hemolvtic disease of the newborn? Specifically, what antibodies are involved and why is diseases caused only after the second exposure?

Answer 1

Hemolysis means as the break down of RBC

Hemolytic disease of the newborn is otherwise called as erythroblastosis fetalis.This is the condition occurs to the newborn when there is an incompatibility between the blood group of the mother and the baby.

Hemolytic disease of the newborn occurs when the Rh negative mother has a baby with an Rh positive father,where the baby's Rh factor is positive.And the case where the baby's red blood cells cross the Rh negative mother.This usually happens at any time at the delivery when the placenta detaches..Here the blood cells of the two circulations mix.This can occur(mixing of two circulation) during a miscarriage or abortion with a fall,or any other invasive procedures such as Chorionic villus sampling or amniocentesis during the prenatal period.

In the first pregnancy the Rh sensitization is not likely.It only become a problem to the next pregnancy with another Rh positive baby.In the next pregnancy the mothers antibodies cross the placenta to fight the Rh positive cells in the babys body.The mothers immune system sees the Rh positive red blood cells of the baby'sas foreign and the immune system of the mother responds by developing antibodies to fight and destroy these foreign cells.As the antibodies activates in the maternal system destroy the red blood cells,the baby may become sick due to making of immature red blood cells.This condition is called as erythroblastosis fetalis during pregnacy,where the mother's antibodies attack the bay's red blood cells thay are broken down and destroyed called as hemolysis.

The main antibodies responsible for the hemolytic disease of the newborn are of IgG type.These antibodies that will transported across the placental barrier to the fetal circulation.The hemolytic disease of the newborn can be seen in incompatibility of the ABO blood group also,but here it is not that much severe as Rh incompatibility.It canbe caused by anti-A and anti-B antibodies.

For the newborn,the condition is called as hemolytic disease of the newborn.

The hemolytic disease can be easily prevented by having a blood test to know their blood type and if in case she is Rh negative and not been sensitized she has to receive a immunoglobulin called as Rh immunoglobulin (RhoGAM).Thus after the sensitization it can stop mother's antibodies from reacting to thebaby's Rh positive cells.