A pregnant patient at risk of hemolytic disease of the fetus and newborn (HDFN) due to a rare P1PK incompatibility was successfully treated with intravenous immunoglobulin (IVIG) and plasma exchange (PE), according to a recently-published article in the Journal of Clinical Apheresis.
HDFN is a consequence of blood type incompatibility between fetus and mother. Blood type is determined by the antigens present in the membrane of the red blood cells (RBCs); when the fetal RBCs have an antigen that the mother doesn’t have , the mother can produce antibodies targeting that antigen producing RBC destruction in a subsequent pregnancy (alloimmunization).
Currently, the two most common causes of HDFN are ABO and Rh incompatibility. However, there are many other antigens in the red blood membrane whose incompatibility could lead to HDFN.
Learn more about HDFN causes and risk factors
P1PK is an antigen present in the red blood cells of over 99% of the global population. Therefore, maternal alloimmunization against this antigen is considered to be extremely rare. Individuals without this antigen can develop antibodies against it even when they have not had any previous exposure.
Consequently, anti-PP1PK antibodies are associated with recurrent spontaneous first-trimester miscarriages, direct placental toxicity, HDFN, and intrauterine growth restriction (IUGR) in pregnant patients,” the authors wrote.
The case involved a 23 year old pregnant woman with a history of a prior miscarriage initially attributed to ABO incompatibility. However, further testing revealed the presence of anti P1PK antibodies. The patient underwent biweekly treatment with IVIG, PE, and close monitoring of fetal anemia.
Neither the mother nor the fetus experienced serious complications during the pregnancy, and no intrauterine transfusions were required. The baby was born after a programmed induction at 38 weeks. The baby was born with normal hemoglobin levels, required no special neonatal care, and was released two days after birth.
“Despite the rare occurrence of maternal anti-PP1PK alloimmunization, successful management is possible with twice-weekly TPE and weekly IVIG adjusted to titers and PV,” the authors concluded.
