The use of ABO+D+cEK match protocol before transfusion could prevent the formation of pathogenic antibodies that could lead to hemolytic disease of the fetus and newborn (HDFN) in a future pregnancy, according to a recently published study in the SMFM 2024 Pregnancy Meeting.
When a person enters into contact with a foreign molecule (antigen), the immune system creates antibodies against the antigen in question to clear it from the body.
As a result of a blood transfusion, a patient can be exposed to antigens present in the donor’s red blood cells (RBCs) but not in the patient’s RBCs. This patient can then form antibodies against this antigen, a process known as alloimmunization. In a future pregnancy in which the baby has some of these antigens, the previously formed antibodies can cross the placenta and cause HDFN.
Learn more about HDFN causes and risk factors
Red blood cell alloimmunization poses challenges in blood transfusion. Notably, antigens D, c, E and Kell can produce severe HDFN after alloimmunization. However, most institutions in the United States only match donors for ABO and D antigens (ABO+D). The authors aimed to investigate the outcomes of a more comprehensive donor matching protocol, including c, E and Kell antigens (ABO+D+cEK), in reducing new alloimmunization.
The authors analyzed 10 studies comparing ABO+D and ABO+D+cEK donor match protocols to determine if there was a difference in the number of new alloimmunizations.
Among 85,385 transfused patients in the 10 selected studies, 43.3% received ABO+D+cEK-matched blood. The ABO+D+cEK protocol was associated with a significantly lower rate of new alloimmunization compared to ABO+D alone.
“New alloimmunization is significantly reduced when using an ABO+D+cEK match protocol. Given sequelae of alloimmunization in pregnancy and thereafter, establishing routine use of ABO+D+cEK donor match in adults of pregnancy potential merits consideration,” the authors concluded.
