Fetal and neonatal alloimmune thrombocytopenia, the platelet equivalent of hemolytic
disease of the fetus and newborn, can have devastating effects on both the fetus and
neonate. Current management of fetal and neonatal alloimmune thrombocytopenia in a
subsequent affected pregnancy involves antenatal administration of intravenous immune
globulin and prednisone to the pregnant woman to prevent the development of severe
fetal thrombocytopenia and secondary intracranial hemorrhage in utero. That therapy
has proven to be highly effective but is associated with maternal side effects and
is expensive. This commentary describes 4 advances that could substantially change
the current approach to detecting and managing fetal and neonatal alloimmune thrombocytopenia
in the near future. The first would be an introduction of a program to screen all
antepartum patients in this country for pregnancies at risk of developing fetal and
neonatal alloimmune thrombocytopenia. Strategies to implement this complex process
have been described. A second advance is testing of cell-free fetal DNA obtained from
maternal blood to noninvasively determine the fetal human platelet antigen 1 genotype.
A third, in preliminary development, is creation of a prophylactic product that would
be the platelet equivalent of Rh immune globulin (RhoGAM). Finally, a fourth major
potential advance is the development of neonatal Fc receptor inhibitors to replace
the current medical therapy administered to pregnant women with an affected fetus.
Neonatal Fc receptor recycles plasma immunoglobulin G to increase its half-life and
is the means by which immunoglobulin G crosses the placenta from the maternal to the
fetal circulation. Blocking the neonatal Fc receptor is an ideal way to prevent maternal
immunoglobulin G antibody from causing fetal and neonatal alloimmune thrombocytopenia
in a fetus at risk of developing that disorder. The pertinent pathophysiology and
rationale for each of these developments will be presented in addition to our thoughts
relating to steps that must be taken and difficulties that each approach would face
for them to be successfully implemented.
Key words
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Article info
Publication history
Published online: April 08, 2021
Accepted:
April 2,
2021
Received in revised form:
March 26,
2021
Received:
December 2,
2020
Footnotes
J.B.B. reports the following disclosures: consultant at CSL Behring (intravenous immunoglobulin manufacturer), UCB, Argenx, Momenta/Janssen (manufacturers of neonatal Fc receptor [FcRn] inhibitors), and Rallybio (company interested in screening and prophylaxis of fetal and neonatal alloimmune thrombocytopenia [FNAIT]) and Data Safety Monitoring Board at CSL Behring. R.L.B. reports the following disclosures: Momenta/Janssen (manufacturers of FcRn inhibitors) and Rallybio (company interested in screening and prophylaxis of FNAIT). E.L.V.H. reports no conflict of interest.
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