Rho Antigen (D)

The Rho antigen, or D antigen, is a highly immunogenic surface protein on red blood cells, encoded by the *RHD* gene. Its presence defines Rh-positive blood type, while its absence defines Rh-negative. The D antigen plays a critical role in transfusion medicine and is the primary target in Hemolytic Disease of the Fetus and Newborn (HDFN) when an Rh-negative mother carries an Rh-positive fetus. Rho(D) immune globulin (anti-D) is administered to Rh-negative pregnant women to prevent alloimmunization.

Other names

Rh(D) antigenRh factor

Rho(D) immune globulin prevents alloimmunization by binding to Rh-positive fetal red blood cells in the maternal circulation and promoting their clearance, thus preventing the mother's immune system from recognizing them as foreign and producing anti-D antibodies. It may also modulate immune response in autoimmune conditions.