In 1901 Karl Landsteiner discovered that when the Blood of one human being was transfused with that of another human being, differences in their Blood leads to shock, jaundice, and renal failure. Since the blood
group antigen and antibody reactions result in the agglutination reaction the antigen is known as agglutinogen and the antibody is known as agglutinin. Blood group antigens are present on the RBC membrane.
According to Land Steiner when an agglutinogen is present on the RBC membrane the corresponding antibody is absent in the plasma. So your ‘blood group’ depends on type antigens which found on the surface of the red blood cell membrane.
Landsteiner law states that a. If a particular agglutinogen (antigen) is present in the RBCs, corresponding agglutinin (antibody) must be absent in the serum.b. If a particular agglutinogen is absent in the RBCs,
the corresponding agglutinin must be present in the serum.
ABO System
Land Steiner found two types of antigens on the RBC they are antigen A and antigen B, similarly there are two types of antibodies in the plasma called antibody alpha and beta antibody. Since this antigen antibody
involved in agglutination reactions the antigen is called as agglutinogen and the antibody is known as agglutinin.According to Land Steiner’s law when an agglutinogen is present on the RBC the corresponding antibody will be absent in the plasma.Based on the presence or absence of antigens and
antibodies human blood is classified into four major groups namely A,B, AB and O.
Blood group A
If you belong to the blood group A, you have A antigens on the surface of your red blood cells and beta antibodies in your blood plasma.
Blood group B
If you belong to the blood group B, you have B antigens on the surface of your red blood cells and alpha antibodies in your blood plasma.
Blood group AB
If you belong to the blood group AB, you have both A and B antigens on the surface of your red blood cells and both alpha and beta antibodies are absent in your blood plasma.
Blood group O
If you belong to the blood group O (null), you donot have the A and B antigens on the surface of your red blood cells but you have both alpha and beta antibodies in your blood plasma.
Rh factor
It is also like the blood group antigen and also present in the cell membrane. Since this antigen was found in Rhesus monkey first they called this antigen as Rhesus antigen or Rh system. Most people are ‘rhesus
positive’ as they have rhesus antigens on their red blood cells. But, about 3 in 20 people do not have rhesus antigen and are said to be ‘rhesus negative
Testing of blood group
Basically, a sample of blood is mixed separately with anti-A antibodies, anti B antibody and Rh antibodies. If the red cells to clump together with anti-A antibodies, then it indicate the presence of A antigens in the blood cells and the person belongs to A group. Similarly if agglutination reaction occurs with anti B antibodies then it indicates the presence of B antigen. When agglutination is found in both anti A and anti B antibodies it
indicates that the person belongs to AB group. If no agglutination found with both antibodies of A and B then it indicates the absence of antigens and the person belongs to O group. Similarly if an anti Rh antibody shows agglutination with the given blood then it indicates the presence of Rh antigens on the blood cells. Hence the person is Rh positive. If no agglutination seen then the person is Rh negative.
Hemolytic disease is the disease in fetus and newborn, characterized by abnormal hemolysis of RBCs. It is due to Rh incompatibility, i.e. the difference between the Rh blood group of the mother and baby. Hemolytic disease leads to erythroblastosis fetalis.
Erythroblastosis fetalis is a disorder in fetus, characterized by the presence of erythroblasts in blood. When a mother is Rh negative and fetus is Rh positive (the Rh factor being inherited from the father), usually the first child escapes the complications of Rh incompatibility. This is because the Rh antigen cannot
pass from fetal blood into the mother’s blood through the placental barrier. However, at the time of parturition (delivery of the child), the Rh antigen from fetal blood may leak into mother’s blood because of placental detachment. During postpartum period, i.e. within a month after delivery, the mother develops Rh antibody in her blood. When the mother conceives for the second time and if the fetus happens to be Rh positive again, the Rh antibody from mother’s blood crosses placental barrier and enters the fetal blood. Thus, the Rh antigen cannot cross the placental barrier, whereas Rh antibody can cross it.Rh antibody which enters the fetus causes agglutination of fetal RBCs resulting in hemolysis. Severe hemolysis in the fetus causes jaundice. To compensate the hemolysis of more and more number of RBCs, there is rapid production of RBCs, not only from bone marrow, but also from spleen and liver. Now, many large and immature cells in proerythroblastic stage are released into circulation. Because of this, the disease is
called erythroblastosis fetalis. Ultimately due to excessive hemolysis severe complica tions develop, viz.
a Severe Anemia:Excessive hemolysis results in anemia and the infant dies when anemia becomes severe.
b.. Hydrops Fetalis:Hydrops fetails is a serious condition in fetus, characterized
by edema. Severe hemolysis results in the develop ment of edema, enlargement of liver and spleen and cardiac failure. When this condition becomes more severe, it may lead to intrauterine death of fetus.. Kernicterus
Kernicterus is the form of brain damage in infants caused by severe jaundice. If the baby survives anemia
in erythroblastosis fetalis (see above), then kernicterus develops because of high bilirubin content.
.Prevention or treatment for erythroblastosis fetalis
i. If mother is found to be Rh negative and fetus is Rh positive, anti D (antibody against D antigen)
should be administered to the mother at 28th and 34th weeks of gestation, as prophylactic
measure. If Rh negative mother delivers Rh positive baby, then anti D should be administered to the mother within 48 hours of delivery. This develops passive immunity and prevents the formation of Rh antibodies in mother’s blood. So, the hemolytic disease of newborn does not occur in a subsequent pregnancy.. If the baby is born with erythroblastosis fetalis, the treatment is given by means of exchange transfusion . Rh negative blood is transfused into the infant, replacing infant’s own Rh positive blood. It will now take at least
6 months for the infant’s new Rh positive blood to replace the transfused Rh negative blood. By this time, all the molecules of Rh antibody derived from the mother get destroyed.
group antigen and antibody reactions result in the agglutination reaction the antigen is known as agglutinogen and the antibody is known as agglutinin. Blood group antigens are present on the RBC membrane.
According to Land Steiner when an agglutinogen is present on the RBC membrane the corresponding antibody is absent in the plasma. So your ‘blood group’ depends on type antigens which found on the surface of the red blood cell membrane.
Landsteiner law states that a. If a particular agglutinogen (antigen) is present in the RBCs, corresponding agglutinin (antibody) must be absent in the serum.b. If a particular agglutinogen is absent in the RBCs,
the corresponding agglutinin must be present in the serum.
ABO System
Land Steiner found two types of antigens on the RBC they are antigen A and antigen B, similarly there are two types of antibodies in the plasma called antibody alpha and beta antibody. Since this antigen antibody
involved in agglutination reactions the antigen is called as agglutinogen and the antibody is known as agglutinin.According to Land Steiner’s law when an agglutinogen is present on the RBC the corresponding antibody will be absent in the plasma.Based on the presence or absence of antigens and
antibodies human blood is classified into four major groups namely A,B, AB and O.
Blood group A
If you belong to the blood group A, you have A antigens on the surface of your red blood cells and beta antibodies in your blood plasma.
Blood group B
If you belong to the blood group B, you have B antigens on the surface of your red blood cells and alpha antibodies in your blood plasma.
Blood group AB
If you belong to the blood group AB, you have both A and B antigens on the surface of your red blood cells and both alpha and beta antibodies are absent in your blood plasma.
Blood group O
If you belong to the blood group O (null), you donot have the A and B antigens on the surface of your red blood cells but you have both alpha and beta antibodies in your blood plasma.
Rh factor
It is also like the blood group antigen and also present in the cell membrane. Since this antigen was found in Rhesus monkey first they called this antigen as Rhesus antigen or Rh system. Most people are ‘rhesus
positive’ as they have rhesus antigens on their red blood cells. But, about 3 in 20 people do not have rhesus antigen and are said to be ‘rhesus negative
Testing of blood group
Basically, a sample of blood is mixed separately with anti-A antibodies, anti B antibody and Rh antibodies. If the red cells to clump together with anti-A antibodies, then it indicate the presence of A antigens in the blood cells and the person belongs to A group. Similarly if agglutination reaction occurs with anti B antibodies then it indicates the presence of B antigen. When agglutination is found in both anti A and anti B antibodies it
indicates that the person belongs to AB group. If no agglutination found with both antibodies of A and B then it indicates the absence of antigens and the person belongs to O group. Similarly if an anti Rh antibody shows agglutination with the given blood then it indicates the presence of Rh antigens on the blood cells. Hence the person is Rh positive. If no agglutination seen then the person is Rh negative.
Hemolytic disease is the disease in fetus and newborn, characterized by abnormal hemolysis of RBCs. It is due to Rh incompatibility, i.e. the difference between the Rh blood group of the mother and baby. Hemolytic disease leads to erythroblastosis fetalis.
Erythroblastosis fetalis is a disorder in fetus, characterized by the presence of erythroblasts in blood. When a mother is Rh negative and fetus is Rh positive (the Rh factor being inherited from the father), usually the first child escapes the complications of Rh incompatibility. This is because the Rh antigen cannot
pass from fetal blood into the mother’s blood through the placental barrier. However, at the time of parturition (delivery of the child), the Rh antigen from fetal blood may leak into mother’s blood because of placental detachment. During postpartum period, i.e. within a month after delivery, the mother develops Rh antibody in her blood. When the mother conceives for the second time and if the fetus happens to be Rh positive again, the Rh antibody from mother’s blood crosses placental barrier and enters the fetal blood. Thus, the Rh antigen cannot cross the placental barrier, whereas Rh antibody can cross it.Rh antibody which enters the fetus causes agglutination of fetal RBCs resulting in hemolysis. Severe hemolysis in the fetus causes jaundice. To compensate the hemolysis of more and more number of RBCs, there is rapid production of RBCs, not only from bone marrow, but also from spleen and liver. Now, many large and immature cells in proerythroblastic stage are released into circulation. Because of this, the disease is
called erythroblastosis fetalis. Ultimately due to excessive hemolysis severe complica tions develop, viz.
a Severe Anemia:Excessive hemolysis results in anemia and the infant dies when anemia becomes severe.
b.. Hydrops Fetalis:Hydrops fetails is a serious condition in fetus, characterized
by edema. Severe hemolysis results in the develop ment of edema, enlargement of liver and spleen and cardiac failure. When this condition becomes more severe, it may lead to intrauterine death of fetus.. Kernicterus
Kernicterus is the form of brain damage in infants caused by severe jaundice. If the baby survives anemia
in erythroblastosis fetalis (see above), then kernicterus develops because of high bilirubin content.
.Prevention or treatment for erythroblastosis fetalis
i. If mother is found to be Rh negative and fetus is Rh positive, anti D (antibody against D antigen)
should be administered to the mother at 28th and 34th weeks of gestation, as prophylactic
measure. If Rh negative mother delivers Rh positive baby, then anti D should be administered to the mother within 48 hours of delivery. This develops passive immunity and prevents the formation of Rh antibodies in mother’s blood. So, the hemolytic disease of newborn does not occur in a subsequent pregnancy.. If the baby is born with erythroblastosis fetalis, the treatment is given by means of exchange transfusion . Rh negative blood is transfused into the infant, replacing infant’s own Rh positive blood. It will now take at least
6 months for the infant’s new Rh positive blood to replace the transfused Rh negative blood. By this time, all the molecules of Rh antibody derived from the mother get destroyed.
No comments:
Post a Comment
Note: Only a member of this blog may post a comment.