Multidisciplinary management of anti-PP1Pk or anti-P alloimmunization during pregnancy: A new case with anti-P and a literature review

Abstract

Background: Red blood cell alloimmunization is the first cause of fetal and neonatal anemia. Alloimmunizations with anti-PP1P^k or anti-P can cause recurrent miscarriages and hemolytic disease of the fetus and newborn in the 2nd and 3rd trimesters of pregnancy. We report on a pregnant patient immunized with anti-P and a history of recurrent miscarriages.

Case report: This P₂^k (GLOB:-1; P1PK:-1,3) patient had a first pregnancy marked by a caesarean at 38 weeks of gestation (WG) for non-reassuring fetal heart rate. Then, she had three early spontaneous miscarriages. The fifth pregnancy began with a high titer of anti-P at 128. Early initiation of treatment with Intravenous Immunoglobulins (IVIg) and plasma exchanges (PE) starting at 5 WG permitted us to reduce the titer of anti-P below 32. A healthy infant was delivered by caesarean at 38 WG without anemia at birth and no exchange transfusion was required.

Discussion and review of the literature: The P and P^k antigens are expressed on placental, trophoblastic, and embryonic cells. This explains why P₁^k (GLOB:-1; P1PK:1,3), P₂^k (GLOB:-1; P1PK:-1,3), or Tj(a-)/p (GLOB:-1; P1PK:-1,-3) patients are prone to recurrent abortions in the first trimester of pregnancy. A literature review demonstrated 87% (68/78) of miscarriages in p patients. However, publication biases are possible with the most severe cases being reported.

Conclusion: Immunizations to P and PP1P^k antigens differ from others in their physiopathology and precocity. The association of PE and IVIg seems to be an effective treatment in the management of anti-PP1P^k or anti-P fetomaternal incompatibilities.

Keywords: anti-GLOB1; anti-P alloimmunizations; anti-PP1Pk; anti-Tja; fetal anemia; fetomaternal red blood cell incompatibility; intravenous immunoglobulin; plasmapheresis; recurrent miscarriages; repeated miscarriages.