Castro Vagner, Kroll Hartmut, Origa Andréa F, Falconi Mônica A, Marques Sílvia B D, Marba Sérgio T, Passini Renato, Annichino-Bizzacchi Joyce M, Costa Fernando F, Santoso Sentot, Arruda Valder R
Hematology and Transfusion Center, the Department of Neonatology, State University of Campinas, UNICAMP, Campinas-SP, Brazil.
Transfusion. 2007 Jan;47(1):59-66. doi: 10.1111/j.1537-2995.2007.01064.x.
Neonatal thrombocytopenia (NT) occurs in 0.5 to 0.9% of unselected Caucasian newborns. However, the prevalence of this complication in other populations is unknown. In this study the prevalence/causes of NT was determined in Brazilian newborns, a population characterized by admixture among Indigenous, Africans, and Caucasians.
A prospective study was carried out in a 3-year period, to determine the prevalence and causes of thrombocytopenia in cord blood samples. Genotyping for HPA 1-5 systems was performed in pairs of mother/neonates with and without thrombocytopenia. All mothers with genotypic mismatches from each group were tested for HPA-specific antibody using the MAIPA technique to identify alloimmunization.
Platelet counts <100 x 10(9)/L were detected in 1.5% of 9,332 unselected newborns. In 0.15%, platelet count was <50 x 10(9)/L. Clinically significant bleeding was rare. Underlying diseases were present in 48% of the thrombocytopenic cases. HPA 1-5 system genotype mismatches occurred in 50% of gestations, but did not predict the risk for thrombocytopenia. Notably, mismatched genotypes for HPA-5 were slightly increased in the thrombocytopenic group. The presence of anti-HPA-5b antibodies was observed in 0.05% of unselected pregnancies, but increased to 12% among mothers of neonates with thrombocytopenia and mismatched genotype (N = 51).
Neonatal thrombocytopenia is common among Brazilian newborns at rates comparable with those described among Caucasians. These data suggest that screening for genotypic HPA mismatch, followed by an HPA-specific immunoassay system, particularly for the HPA-5 system, among mothers of newborns with thrombocytopenia in our population would allow the identification of pregnancies at risk of alloimmune thrombocytopenia.
在未经筛选的白种人新生儿中，新生儿血小板减少症（NT）的发生率为0.5%至0.9%。然而，该并发症在其他人群中的患病率尚不清楚。在本研究中，对巴西新生儿（一个以原住民、非洲人和白种人混合为特征的人群）NT的患病率/病因进行了测定。
在3年期间进行了一项前瞻性研究，以确定脐带血样本中血小板减少症的患病率和病因。对有和没有血小板减少症的母婴对进行HPA 1 - 5系统基因分型。使用MAIPA技术对每组基因不匹配的所有母亲进行HPA特异性抗体检测，以确定同种免疫。
在9332例未经筛选的新生儿中，1.5%的新生儿血小板计数<100×10⁹/L。在0.15%的新生儿中，血小板计数<50×10⁹/L。临床上显著的出血很少见。48%的血小板减少症病例存在基础疾病。HPA 1 - 5系统基因不匹配发生在50%的妊娠中，但不能预测血小板减少症的风险。值得注意的是，血小板减少症组中HPA - 5的不匹配基因型略有增加。在0.05%的未经筛选的妊娠中观察到抗HPA - 5b抗体的存在，但在血小板减少症且基因型不匹配的新生儿母亲中（N = 51）增加到12%。
新生儿血小板减少症在巴西新生儿中很常见，发生率与白种人描述的发生率相当。这些数据表明，在我们人群中对血小板减少症新生儿的母亲进行基因HPA不匹配筛查，随后进行HPA特异性免疫测定系统检测，特别是针对HPA - 5系统，将有助于识别有同种免疫性血小板减少症风险的妊娠。
