Blood group Rh(D) antigen (RhD) (RhD)

The Blood group Rh(D) antigen is a multi-pass transmembrane protein located on the erythrocyte membrane, encoded by the RHD gene (UniProt: P18577). It plays a critical role in maintaining the structural integrity of the red blood cell and is part of a complex involved in ammonium transport (NCBI Gene ID: 6000). Clinically, RhD is the most immunogenic antigen in the Rhesus system; exposure of an Rh-negative individual to Rh-positive blood can lead to the production of anti-D antibodies, causing hemolytic transfusion reactions or hemolytic disease of the newborn (StatPearls: Rh Incompatibility). Rho(D) immune globulin is a key therapeutic agent that targets this antigen to prevent maternal alloimmunization by clearing fetal Rh-positive cells from maternal circulation (PubMed: PMID 29262015). Additionally, it is used in the treatment of immune thrombocytopenic purpura (ITP), where it coats RhD-positive cells to saturate Fc receptors and prevent platelet destruction (NIH: MedlinePlus).

Other names

Rh polypeptide 1RhD proteinRhesus blood group D antigenCD240DRHRHCU

Rho(D) immune globulin binds to the RhD antigen on red blood cells. In pregnancy, it prevents Rh-negative mothers from becoming sensitized to Rh-positive fetal cells by facilitating their clearance and suppressing the primary immune response. In immune thrombocytopenic purpura (ITP), the anti-D antibodies coat the patient's RhD-positive red blood cells, which then saturate Fc receptors on splenic macrophages, thereby reducing the destruction of platelets.