Sat Mar 23, 2024 11:33 pm by globalturbo
THE RHESUS SYSTEM
The Rhesus system was simultaneously discovered in 1937 by Levine and Stester and in 1940 by Karl Landsteiner and Alexander S. Wiener. Levine and Stetser discovered the actual D antigen, and Landsteiner and Wiener discovered the anti-D antibody.
You don't have to have Rh negative parents to be an rh negative blood type. Two people who are rh positive can have an rh negative baby. This is because the rh protein is considered to be a recessive allele, just like the blood type O. Your rh positive parents can each be what is called Heterozygous, which means they carry one rh negative allele and one rh positive allele. If both parents provide a copy of the rh negative allele, then the child will be rh negative, because they have two negative alleles. If one parent donates an rh negative allele, and the other parent donates an rh positive allele, then the child will be rh positive- because the rh positive alleles are dominant.
The following example illustrates the point. The left hand cell is fully rh positive, the middle cell has noticably less D (+) proteins- so that cell is considered to be weak D. A person with "weak D" blood is +/-. The cell on the right shows a blood cell with no D proteins, it is Rh negative.
If your red blood cells SPECIFICALLY do not have the D protein, you are considered to be Rh D negative, also known as Rh negative, or Rhesus negative. The old way of writing this was Du or rr. The new way of writing it is dd. If you do not have ANY of the rhesus proteins, then you are considered to be rh NULL which is extremely rare. An rh NULL person is at risk any time there is blood transference, even if the donor is rh negative.
Because of the specificity of blood types, it's important to note that a negative reaction can occur when ANY two "un-matched" blood types are mixed- it's not just rh negatives that are in danger of this. However, when an rh D negative produces antibodies to rh positive blood, it's a particularly potent antibody and can cause very serious problems during transfusions or pregnancy.
The percentage of Rh (D) negative blood varies within ethnic groups, and is most commonly found in Caucasian peoples of European descent. The following is a breakdown of occurrence in some ethic and racial groups.
According to Dr. Luigi Cavalli-Sforza the highest percentage of rh negative blood is in the tribes still living in the Atlas mountains, the next highest are the Basque.
In a transfusion situation, an rh (D) negative individual, should receive only A-B-O compatible rh negative blood because an rh negative body will not recognize the positive rh (D) proteins (or antigens) as SELF and will attack even an A-B-O compatible blood type if it has the additional (D) protein (antigen). Unfortunately, the availability of rh negative blood is limited by eligible, available donors and some areas of the world just don’t have much of it! In cases where no rh negative blood can be found, then the compatible rh positive blood type will be used. It’s always a good idea for rh negatives to bank their own blood, and/or have a contact list of people who could donate to you if you ever need it.
50% of rh negative people who have developed antibodies will naturally purge them from their body. The antibodies do not cause personal physical harm to the rh negative individual, and only becomes a problem in a transfusion situation, or pregnancy with an rh positive child.
When alloimmunization occurs, the body produces antibodies which attach themselves to the offending antigens and essentially suffocate them. This is called Hemolysis. The process of hemolysis is called a hemolytic reaction.
In pregnancy, a hemolytic reaction in the fetus is called Hemolytic Disease of the Newborn, and can occur with any difference in the Rhesus System proteins. However, a reaction to the Rh (D) proteins is considered the most severe form of Hemolytic Disease of the Newborn and is commonly referred to as Rh Disease. Symptoms range from mild to severe and can include anaemia and heart failure.
Thanks to: http://rhnegativeblood.ning.com
THE RHESUS SYSTEM
Also known as the Rhesus Factor, the Rh factor, or Rh system.
The Rhesus system was simultaneously discovered in 1937 by Levine and Stester and in 1940 by Karl Landsteiner and Alexander S. Wiener. Levine and Stetser discovered the actual D antigen, and Landsteiner and Wiener discovered the anti-D antibody.
In 1939 Philip Levine and Rufus E. Stetson published their findings about a family who had a stillborn baby who died of hemolytic disease of the newborn. The mother was aged 25 and it was her second pregnancy and she suffered blood loss at the delivery. Both parents were blood group O and the husband's blood was used to give the mother a blood transfusion, but the mother suffered a severe transfusion reaction. They investigated this transfusion reaction. Since the mother and the father were both blood group O, they concluded that there must be a previously undiscovered blood group antigen that was present on the husband's RBCs but was not present on the mother's RBCs and that the mother had formed antibodies against the new blood group antigen. This suggested for the "first time" that a mother could make blood group antibodies because of immune sensitization to her fetus's RBCs.
Karl Landsteiner and Alexander S. Wiener noticed that when 85% of human blood was mixed with rabbit blood, the antibody that was produced was similar to what happened when the test subjects were exposed to Rhesus monkey red blood cells. They also noticed that 15% of blood did not cause this problem. Through their research, the Rh Negative blood type was brought to the attention of the people responsible for blood transfusions. It's interesting to note that although the monkey proteins were subsequently found to be different than the human proteins, the name Rhesus System stuck.
We now know that the Rhesus system is the second most important blood consideration other than the A-B-O type system that is discussed above. Currently, in the Rhesus system, or Rh system, there are over 100 defined blood-group antigens (proteins), among which the 5 antigens D, C, c, E, and e are the most important ones. Your red blood cells either have these proteins or they don’t. We inherit our Rh status from our parents, just as we inherit our A-B-O type.You don't have to have Rh negative parents to be an rh negative blood type. Two people who are rh positive can have an rh negative baby. This is because the rh protein is considered to be a recessive allele, just like the blood type O. Your rh positive parents can each be what is called Heterozygous, which means they carry one rh negative allele and one rh positive allele. If both parents provide a copy of the rh negative allele, then the child will be rh negative, because they have two negative alleles. If one parent donates an rh negative allele, and the other parent donates an rh positive allele, then the child will be rh positive- because the rh positive alleles are dominant. The following example illustrates the point. The left hand cell is fully rh positive, the middle cell has noticably less D (+) proteins- so that cell is considered to be weak D. A person with "weak D" blood is +/-. The cell on the right shows a blood cell with no D proteins, it is Rh negative.
 |
Free Emergency Medical ID Wallet Card Here |
Because of the specificity of blood types, it's important to note that a negative reaction can occur when ANY two "un-matched" blood types are mixed- it's not just rh negatives that are in danger of this. However, when an rh D negative produces antibodies to rh positive blood, it's a particularly potent antibody and can cause very serious problems during transfusions or pregnancy.
The percentage of Rh (D) negative blood varies within ethnic groups, and is most commonly found in Caucasian peoples of European descent. The following is a breakdown of occurrence in some ethic and racial groups.
Rates of Rh negative blood among ethnic and racial groups
- White - 15-16%
- African American - 8%
- African - 4%
- Basque (region of Spain/France) - 30-35%
- Asian - Less than 1%
- Asian American - 1%
- American Indian/Inuit - 1-2%
- Eurasian - 2-4%
According to Dr. Luigi Cavalli-Sforza the highest percentage of rh negative blood is in the tribes still living in the Atlas mountains, the next highest are the Basque.
In a transfusion situation, an rh (D) negative individual, should receive only A-B-O compatible rh negative blood because an rh negative body will not recognize the positive rh (D) proteins (or antigens) as SELF and will attack even an A-B-O compatible blood type if it has the additional (D) protein (antigen). Unfortunately, the availability of rh negative blood is limited by eligible, available donors and some areas of the world just don’t have much of it! In cases where no rh negative blood can be found, then the compatible rh positive blood type will be used. It’s always a good idea for rh negatives to bank their own blood, and/or have a contact list of people who could donate to you if you ever need it.
When an rh negative does not develop antibodies to rh positive blood, it’s called Sensibiliation. There has been no research done to determine why some rh negatives become sensitized and others do not.Alloimmunization or sensitization refers to the immune process that occurs when the rh negative body reacts to rh positive blood. The process of
Alloimmunization or sensitization is a simple immune response where the body detects something that is not SELF, and sends antibodies to fight it. The amount of blood exposure that causes alloimmunization varies. Some rh negative people have developed antibodies to as little 0.01 ml. of rh positive blood. There are others, (about 30% of rh negative people) who will NEVER develop an immune response, even when challenged with large amounts of rh positive blood and or repeated exposure.
50% of rh negative people who have developed antibodies will naturally purge them from their body. The antibodies do not cause personal physical harm to the rh negative individual, and only becomes a problem in a transfusion situation, or pregnancy with an rh positive child.
When alloimmunization occurs, the body produces antibodies which attach themselves to the offending antigens and essentially suffocate them. This is called Hemolysis. The process of hemolysis is called a hemolytic reaction.
In pregnancy, a hemolytic reaction in the fetus is called Hemolytic Disease of the Newborn, and can occur with any difference in the Rhesus System proteins. However, a reaction to the Rh (D) proteins is considered the most severe form of Hemolytic Disease of the Newborn and is commonly referred to as Rh Disease. Symptoms range from mild to severe and can include anaemia and heart failure.
Thanks to: http://rhnegativeblood.ning.com
Yes! Your rhesus status is determined by both of your parents through the donation of alleles or proteins which are the building blocks for genetic expression. 
