Rh blood group system proteins (RhD and RhCE) (RhD/RhCE)

The Rh blood group system consists of two highly homologous transmembrane proteins, RhD and RhCE, expressed exclusively on red blood cells (UniProt P18577, P18175). These proteins are essential for maintaining the structural integrity of the erythrocyte membrane and are thought to function as part of a core complex involved in the transport of gases like ammonia and carbon dioxide (NCBI Gene ID 6000; PMID: 18635528). The RhD antigen is particularly significant due to its high immunogenicity; Rh-negative individuals exposed to RhD-positive blood can develop anti-D antibodies (StatPearls: Rh Incompatibility). This sensitization is the underlying cause of hemolytic disease of the fetus and newborn (HDFN), where maternal IgG antibodies cross the placenta and destroy fetal erythrocytes (PMID: 25331578). Therapeutic management involves the use of Rho(D) immune globulin to prevent maternal alloimmunization in Rh-negative women carrying Rh-positive fetuses. Additionally, Rh antigens are critical markers for blood transfusion compatibility to prevent life-threatening hemolytic reactions. The RhCE protein carries the C/c and E/e antigens, which, while less immunogenic than D, can also cause transfusion reactions and HDFN (PMID: 15273211). These antigens are encoded by two closely linked genes on chromosome 1, RHD and RHCE, which arose through gene duplication.

Other names

Rhesus factorRh antigenRh blood group D antigenRh blood group CcEe antigensRHDRHCEBlood group Rh erythrocyte marker

Rho(D) Immune Globulin provides passive immunity by binding to RhD-positive fetal erythrocytes in the maternal circulation, facilitating their rapid clearance by the spleen before the maternal immune system can initiate an active immune response, a process known as antibody-mediated immune suppression (AMIS) (PMID: 21633031).