They are a type of antigen that some people carry on their red blood cells. They are called "rhesus" because they were initially identified and studied on the red blood cells of rhesus monkeys, then were later also found in humans. If a person has Rh+ blood type they have this antigen, if a person has Rh- blood type they do not.
They are important in blood transfusions in that a person with Rh+ blood type can receive either Rh+ or Rh- blood with no problems, but a person with Rh- blood type can only receive Rh- blood (Rh+ blood could kill him when antibodies from his immune system attack the rhesus antigen, causing massive blood clotting).
They are important in pregnancy in that a woman with Rh- blood type has a much higher chance of miscarriage if her baby has Rh+ blood type.
Note: there are roughly 30 different classes of blood type antigens, not just the familiar A, B, and Rh antigens. Most however are very rare.
The blood type notation A Rh- indicates which antigens and antibodies are present in the blood. A indicates there are A antigens. Rh+ indicates there are Rh antigens. B antibodies. If there are A and Rh antigens but no B antigens, the antibodies in the blood plasma are B antibodies.
There are two main types of antigens on erythrocytes - ABO antigens and Rh antigens. ABO antigens include A and B antigens while Rh antigens include RhD antigen. These antigens play a crucial role in determining blood type compatibility for blood transfusions.
If red blood cells lack Rh antigens, the blood is called Rh-negative.
Blood antigens A and B are located on the surface of red blood cells, while the Rh antigen (Rh factor) is also found on the surface of red blood cells. These antigens determine an individual's blood type.
The Rh- person has no Rh antigens, so their body does not recognize the Rh antigens on the Rh+ donor blood as foreign. However, the B antigens on the donor blood are recognized by the recipient's immune system as foreign, leading to an immune response against the B antigens. This can result in a transfusion reaction if not properly managed.
There are about 45 different Rh antigens, the most important of which is the D-antigen.
The most important antigens in the Rh group are the RhD antigen and the RhC, RhE, Rhc, and Rhe antigens. The RhD antigen is the most clinically significant, as the presence or absence of this antigen determines an individual's Rh blood type (positive or negative). These antigens are important in blood transfusions and can cause hemolytic disease of the newborn if not properly matched during pregnancy.
Antigens. Your blood type depends if you have A, B, AB, or none of those antigens (O). These antigens can also be positive or negative depending on whether you have the Rh antigen, or Rh factor.
The Rh factor refers to the presence or absence of a specific protein on the surface of red blood cells, while A, B, and O antigens refer to different types of carbohydrates found on the cell membrane. The Rh factor is a separate antigen system from the ABO system and does not directly influence blood typing based on A, B, and O antigens.
The serum used to prevent sensitization to Rh antigens is called Rh immune globulin (RhIG) or RhoGAM. It is typically given to Rh-negative mothers during pregnancy or after giving birth to prevent their immune system from developing antibodies against Rh-positive red blood cells in case of Rh incompatibility between the mother and baby.
RhoGAM
Antigens or RH factor