Alloimmunization from Non-RhD antigens - Challenges and opportunities

Fetal and neonatal anemia resulting from red blood cell (RBC) alloimmunization, also known as hemolytic disease of the fetus and newborn (HDFN), remains a significant cause of morbidity and mortality globally. Though Rhesus group D (RhD) is the most common RBC antigen known to cause alloimmunization, maternal-fetal RBC antigen incompatibility and subsequent alloimmunization can result from over 50 RBC surface antigens. Moreover, despite the development and wide-spread use of RhD immune globulin, (RhIG) and the initial decrease in RhD HDFN, there has been a recent persistence in the burden of disease from RhD incompatibility, as well as a relative increase in the incidence of non-RhD alloimmunization cases. The goal of this review is to present data regarding the incidence and implications of non-RhD group alloimmunization to highlight this ongoing global health care issue. We will also detail the latest data on alloimmunization care, management, and present areas that would benefit from further research and education.