Summary of the Rh Blood Group System O '' '.

Introduction to Rh Blood Group System

  • Rh antigens are protein-based and highly immunogenic.
  • Rh Definition:
    • RhD positive: presence of RhD antigen.
    • RhD negative: absence of RhD antigen.
  • Second most important blood group after ABO.

Historical Context

  • Levine & Stetson: Identified hemorrhagic transfusion reactions.
  • Landsteiner & Wiener: Studied antibodies from transfusions in animals.

Fisher-Race and Wiener Terminologies

  • Fisher-Race: Three closely linked genes produce Rh antigens (D, C, c, E, e).
  • Wiener: Single gene theory producing multiple blood factors (as agglutinogens).
  • Rosenfield system: Numeric designation for Rh antigens.

Molecular Genetics and Rh Genes

  • Key Genes: RHD (RhD antigen) and RHCE (various Rh antigens).
  • RHAG gene involved in coexpression of Rh antigens.
  • Importance of genetic backgrounds and mutations in Rh phenotypes.

Rh Phenotypes

  • Rh-positive: Inherit RHD genes.
  • Rh-negative: Caused by mutations in various ethnic backgrounds.

Biochemistry of Rh Antigens

  • Non-glycosylated proteins integral to RBC membranes.
  • Functions include maintaining integrity and transport.

Weak D Variations

  • Weak expression of D antigen that can complicate typing.
  • Categories: Weak D, Partial D, Del.

Rh Antibody Detection

  • Most Rh antibodies are IgG types, persist long-term, and can cross the placenta.
  • High clinical significance of IgG1 and IgG3.

Clinical Considerations

  • Rh-positive blood is crucial; careful transfusion practices are essential to avoid reactions.
  • Rh immune globulin prevents hemolytic disease of the fetus and newborn (HDFN).

Rhnull and Rhmod Syndromes

  • Rhnull: Total lack of Rh antigens.
  • Rhmod: Partial suppression caused by mutations affecting RhAG.

Landsteiner-Weiner (LW) Blood Group System

  • Similarity between Rh and LW systems; anti-LW reacts with D-positive RBCs, less with D-negative or Rhnull.

Unusual Phenotypes and Rare Alleles

  • Various rare Rh phenotypes and alleles exist, affecting blood compatibility.