A newborn child with an uneventful pregnancy history was diagnosed with fetal and neonatal alloimmune thrombocytopenia (FNAITFetal and neonatal alloimmune thrombocytopenia A rare condition in which a mother’s immune system attacks fetal platelets, leading to dangerously low platelet levels before and/or after birth.) at birth, necessitating continuous platelet transfusionPlatelet transfusion A treatment for newborns with very low platelet counts that ideally uses HPA-compatible or washed maternal platelets. therapy, according to a case report recently published in Immunohematology.
A female child was born via spontaneous vaginal delivery at full term. Within the first day of life, the child was found to have severely low platelet levels, causing doctors to suspect a diagnosis of FNAIT.
The child was administered intravenous immunoglobulinIntravenous immunoglobulin A treatment given to pregnant women with a history of FNAIT or known alloantibodies. IVIG reduces the immune reaction against fetal platelets. (IVIGIntravenous immunoglobulin A treatment given to pregnant women with a history of FNAIT or known alloantibodies. IVIG reduces the immune reaction against fetal platelets.) and two units of platelet transfusions. Following these therapies, the child’s platelets rose to 265 x 109/L, which is within normal range.
Because the child’s abnormally low platelet countPlatelet count A measure of how many platelets are in the blood. FNAIT is characterized by severely reduced counts in a fetus or newborn. was a surprise, with no known prior indications that this risk was present, doctors tested the mother’s blood for anti-human platelet antigenHuman platelet antigen Proteins found on the surface of platelets. Incompatibility between maternal and fetal human platelet antigens can trigger FNAIT. (HPAHuman platelet antigen Proteins found on the surface of platelets. Incompatibility between maternal and fetal human platelet antigens can trigger FNAIT.) antibodies and anti-human leukocyte antigen (HLA) Class I antibodies to search for clues regarding the source of the child’s likely diagnosis of FNAIT.
Read more about FNAIT testing and diagnosis
HPA typing of the mother found maternal-fetal HPA-1 incompatibility, as well as mismatch in terms of HLA Class I. Studies showed a rigorous maternal reaction against fetal platelets, thus explaining the low platelet count of the child.
The final diagnosis was FNAIT secondary to anti-HPA-1b and anti-HLA antibodies. The child continued to receive platelet transfusions, this time with platelets lacking HPA and HLA antigens that were targeted. This resulted in the child’s clinical condition being stabilized. By two months of age, she no longer required platelet transfusions.
One of the most common reasons that FNAIT goes unrecognized is a lack of awareness of this condition, in addition to technical limitations in antibody detection. The majority of guidelines focus on anti-HPA-1a, meaning that other antibodies are typically left uninvestigated. Because there is a lack of standardization in terms of screening protocols, delayed diagnosis is frequent, which poses a substantial risk to the health of the fetus/newborn involved.
“Postnatally [ie, after birth], early HPA/HLA typing and alloantibodyAlloantibody An antibody a pregnant woman develops in response to fetal platelets that carry a different human platelet antigen. These antibodies can cross the placenta and destroy fetal platelets. screening are essential,” the authors of the report wrote. “Platelet transfusions—ideally using HPA/HLA-matched units—should not be delayed.”
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