Placenta-associated biomarkers and pregnancy outcome in HPA-1a alloimmunization: A prospective cohort study.

Introduction: Fetal and neonatal alloimmune thrombocytopenia (FNAIT) results from parental incompatibility in human platelet antigens (HPA) and subsequent maternal sensitization. The HPA-1a epitope is also expressed on placental tissue. Chronic placental inflammation and lower birth weight is observed more often in HPA-1a alloimmunized pregnancies, suggesting a placental component in the pathophysiology of FNAIT.

What's with the boys? Lower birth weight in boys from HPA-1a alloimmunized pregnancies - New insights from a large prospective screening study in Poland.

Fetomaternal incompatibility in human platelet antigens (HPAs) can cause maternal alloimmunization, which in turn may lead to thrombocytopenia with or without intracranial hemorrhage (ICH) in the fetus or newborn. Retrospective studies suggest that boys from alloimmunized mothers may have higher risk of ICH and lower birth weight than girls. The objective of this study was to assess how maternal HPA-1a alloimmunization, sex of the neonate and birth weight relates in a large prospective cohort.

Platelet alloimmunization is associated with low grade chronic histiocytic intervillositis - A new link to a rare placental lesion?

Introduction: Maternal alloimmunization against human platelet antigen (HPA)-1a has been implied to mediate both reduced birth weight and chronic placental inflammation. Fetal growth restriction is associated with different types of chronic inflammation in the placenta, mainly chronic histiocytic intervillositis and chronic villitis. The aim of this prospective study was to do a systematic examination of placentas from HPA-1a alloimmunized pregnancies, with focus on the histopathological and immunohistochemical diagnosis of variants of chronic inflammation.

Prediction of fetal blood group and platelet antigens from maternal plasma using next-generation sequencing.

Background: Fetuses whose mothers have produced antibodies to red blood cell (RBC) or platelet antigens are at risk of being affected by hemolytic disease or alloimmune thrombocytopenia, respectively, only if they inherit the incompatible antigen. Noninvasive diagnosis of the fetal antigen is employed for management of immunized pregnancies, but the specific detection of SNPs, encoding the majority of antigens, in maternal plasma is still a challenge. We applied targeted next-generation sequencing (NGS) to predict the fetal antigen based on the detection of fetomaternal chimerism.

Noninvasive prenatal HPA-1 typing in HPA-1a negative pregnancies selected in the Polish PREVFNAIT screening program.

Background: Anti-HPA-1a alloantibodies in HPA-1a negative mothers can lead to fetal/neonatal alloimmune thrombocytopenia (FNAIT). Noninvasive prenatal testing (NIPT) of HPA-1a determines fetuses at risk and the course of maternal antenatal treatment.

Study Design And Methods: The aim was to develop and validate HPA-1a NIPT by real-time polymerase chain reaction (PCR) or next-generation sequencing (NGS) for a high-throughput screening setting.