Abstract：
BACKGROUND: Fetal and Neonatal Alloimmune Thrombocytopenia (FNAIT) results from maternal platelet alloimmunization against paternal antigens inherited by the fetus, most often due to the Human Platelet Antigen (HPA)-1 system in Caucasians. We investigated in 2023, a 30-year-old Caucasian woman Gravida 2 Para 1 who gave birth at 35 weeks of gestation to a male (body weight 2210 g) without signs of bleeding. A severe thrombocytopenia (platelet count at 3 G/L) was discovered incidentally a few hours after delivery in the context of the management of a respiratory distress. The newborn recovered after one platelet concentrate transfusion and normalized his platelet count at Day 5.
METHODS: FNAIT investigation was performed according to guideline recommendations. Platelet genotyping was carried out by multiplex PCR. Maternal serological investigation included Monoclonal Antibody-specific Immobilization of Platelet Antigens method (MAIPA) and Luminex technology.
RESULTS: Parental and newborn genotyping pointed out an HPA-4 incompatibility between the mother and the newborn and the father. Serological investigation revealed an anti-HPA-4b alloantibody confirming the diagnosis of neonatal alloimmune thrombocytopenia.
CONCLUSIONS: We described the third case of anti-HPA-4b alloantibody discovered in a Caucasian mother. This case strengthens the need for reference laboratory to genotype a panel of HPA alleles reflecting local genetic population diversity and for crossmatch of maternal serum with fresh paternal platelets in clinical suspected cases of neonatal alloimmune thrombocytopenia.
METHODS: FNAIT investigation was performed according to guideline recommendations. Platelet genotyping was carried out by multiplex PCR. Maternal serological investigation included Monoclonal Antibody-specific Immobilization of Platelet Antigens method (MAIPA) and Luminex technology.
RESULTS: Parental and newborn genotyping pointed out an HPA-4 incompatibility between the mother and the newborn and the father. Serological investigation revealed an anti-HPA-4b alloantibody confirming the diagnosis of neonatal alloimmune thrombocytopenia.
CONCLUSIONS: We described the third case of anti-HPA-4b alloantibody discovered in a Caucasian mother. This case strengthens the need for reference laboratory to genotype a panel of HPA alleles reflecting local genetic population diversity and for crossmatch of maternal serum with fresh paternal platelets in clinical suspected cases of neonatal alloimmune thrombocytopenia.
摘要：
背景：胎儿和新生儿同种免疫性血小板减少症（FNAIT）是由母体血小板同种免疫针对胎儿遗传的父系抗原引起的，最常见的原因是白种人的血小板抗原（HPA）-1系统。我们在2023年调查了一名30岁的白人女性Gravida2Para1，她在妊娠35周时分娩了一名男性（体重2210g），没有出血迹象。在治疗呼吸窘迫的情况下，分娩后数小时偶然发现了严重的血小板减少症（血小板计数为3G/L）。新生儿在一次血小板浓缩物输注后恢复，并在第5天使他的血小板计数恢复正常。
方法：根据指南建议进行FNAIT调查。通过多重PCR进行血小板基因分型。母体血清学研究包括单克隆抗体特异性固定血小板抗原方法（MAIPA）和Luminex技术。
结果：父母和新生儿的基因分型指出了母亲和新生儿以及父亲之间的HPA-4不相容。血清学研究显示抗HPA-4b同种抗体证实了新生儿同种免疫性血小板减少症的诊断。
结论：我们描述了在白种人母亲中发现的第三例抗HPA-4b同种抗体。这种情况加强了参考实验室对反映局部遗传种群多样性的一组HPA等位基因进行基因分型的需求，以及在新生儿同种免疫性血小板减少症的临床疑似病例中，将母体血清与新鲜的父系血小板交叉匹配的需求。
方法：根据指南建议进行FNAIT调查。通过多重PCR进行血小板基因分型。母体血清学研究包括单克隆抗体特异性固定血小板抗原方法（MAIPA）和Luminex技术。
结果：父母和新生儿的基因分型指出了母亲和新生儿以及父亲之间的HPA-4不相容。血清学研究显示抗HPA-4b同种抗体证实了新生儿同种免疫性血小板减少症的诊断。
结论：我们描述了在白种人母亲中发现的第三例抗HPA-4b同种抗体。这种情况加强了参考实验室对反映局部遗传种群多样性的一组HPA等位基因进行基因分型的需求，以及在新生儿同种免疫性血小板减少症的临床疑似病例中，将母体血清与新鲜的父系血小板交叉匹配的需求。
