- The Rh blood grouping system, also known as the Rhesus blood group system, is the second most significant blood group system after the ABO system and determines the Rh factor.
- It was first discovered in 1940 by Karl Landsteiner and Alexander Wiener during experiments with the blood of rhesus monkeys, which is how the system got its name.
- The Rhesus system is particularly important in blood transfusion medicine, pregnancy, and certain medical conditions.
Components of the Rhesus (RH) System
- The Rhesus blood group system is based on the presence or absence of the Rhesus antigen, also known as the Rhesus factor, on the surface of red blood cells (RBCs).
- The most significant Rhesus antigen is the D antigen.
Advertisements
Rh Antigens
- D Antigen: The most immunogenic and clinically important antigen in the Rhesus system.
- Other Antigens: There are other Rhesus antigens, such as C, c, E, and e, but the D antigen is the primary focus due to its strong immunogenicity.
Rh Status
- Rh Positive (Rh⁺)
- Presence of D Antigen: Individuals have the D antigen on the surface of their RBCs.
- Frequency: Approximately 85
- Rh Negative (Rh⁻)
- Absence of D Antigen: Individuals lack the D antigen on the surface of their RBCs.
- Frequency: About 15
Advertisements
Advertisements
Clinical Significance of the Rhesus System
Blood Transfusions
- Compatibility: Rhesus status must be matched during blood transfusions to prevent hemolytic reactions. A Rh-negative individual should not receive Rhesus positive blood, as their immune system may produce anti-D antibodies that can attack the transfused RBCs.
- Universal Donor and Recipient:
- Universal Donor for Rhesus System: Rhesus negative blood can be given to both Rhesus negative and Rhesus positive recipients.
- Universal Recipient for Rhesus System: Rhesus positive individuals can receive Rh positive or Rh-negative blood.
Advertisements
Pregnancy Considerations
- If a Rhesus negative woman is pregnant with a Rhesus positive baby, she may develop antibodies against the baby’s blood (Rhesus sensitization).
- This is particularly a concern in subsequent pregnancies with a Rhesus-positive baby, as the mother’s antibodies can attack the fetal red blood cells.
- To prevent this, Rhesus negative pregnant women often receive Rhesus immunoglobulin (RhIg) injections.
Thank you for reading from Firsthope's notes, don't forget to check YouTube videos!
