Rh Blood Group Flashcards
What are the antigens in the Rh system
- C
- c
- E
- e
When was the Rh blood group system first described and by who?
1939 by Levine and Stetson
What chromosome is the Rh locus found on?
Chromosome 1
What two genes are respnsible for the Rh antigens and what chromosome are they linked on?
the genes RHD and RHCE are responsible for the RH antigens. they are closely linked on chromosome 1
What is the third gene which produces a protein that incorporates the RH antigens into the red cell membrane
The RH associated glycoprotein gene (RH AG)
On which chromosome is the RH AG gene located
Chromosome 6
Function of the RH AG gene
It produces a protein, the Rh associated glycoprotein, that is required for the incorporation of the RH antigens into the red cell membrane
What is the two-locus theory
- One locus carries the Rh D gene
- A second closely linked gene carries the RHCE gene that codes for Cc and Ee antigens
- C and c and E and e are antithetical genes, meaning that a protein can only express one of them
What does d or D- indicate
The absence of the D antigen
At how many weeks has the D antigen been detected on the cells of the embryo
6 weeks
What does the Rh D antigen being very antigenic mean
The Rh D antigen is very antigenic. This means that it induces an immune response producing the anti D antibody if its introduced into individuals who are Rh D negative (lack the D antigen)
Describe Rh D Grouping
- A patients blood sample must be tested in duplicate with IgM monoclonal anti D grouping reagent prior to transfusion
- Two commercial anti D antisera are used to distinguish between D+ and D- red cell samples
Why are two anti D grouping antisera used to detect the presence or absence of the D antigen on red cells (2 reasons)
- Act as a recheck
- To detect anomalies
What are Rh antibodies stimulated by (2)
- Pregnancy
- Transfusion
When may Rh D- individuals / Rh D- pregnant women produce the anti D antibody
If exposed to the D antigen
