Department of Laboratory Medicine, AZ Sint-Jan Hospitals Brugge-Oostende, Brugge, Belgium.
Transfusion. 2022 May;62(5):1103-1109. doi: 10.1111/trf.16868. Epub 2022 Mar 30.
Hemolytic disease of the fetus and newborn (HDFN) due to rhesus D (RhD) immunization is a potentially life-threatening situation for which use of Rh Immunoglobulin (RhIg) has decreased risk drastically. Determination of fetal RHD on maternal plasma can be used to restrict prenatal RhIg administration to women carrying an RhD-positive child, avoiding unnecessary administration of blood-derived products.
The aim of this study is to determine the performance of fetal RHD typing in our center. We prospectively collected 205 fetal RHD and 127 serological cord blood RhD data from RhD-negative women starting at 11 weeks of pregnancy (from October 2019 to October 2021). Real-time polymerase chain reaction targeting RHD exon 5 and 7 was used, similar to the screening program in The Netherlands, supplemented with an amplification control (beta-actin; ACTB) and a sex determination marker located on the Y-chromosome (SRY gene).
Fetal RHD testing reached a sensitivity and specificity of 100%. No false-negative nor false-positive results were reported. Inconclusive results (6%, 13/205) were due to weak amplification in 10 cases, a maternal RHD variant in 2 cases (RHD*01N.71 and partial DVI), and a fetal RHD variant (partial DVI) in 1 case. Unnecessary administration of RhIg prophylaxis was avoided in 33% of cases and on the other hand was administered in one case (fetal partial DVI) which would have been missed with cord blood serology.
This study demonstrates the high accuracy of routine prenatal fetal RHD gene screening after 11 weeks of pregnancy, encouraging routine clinical practice.
由于 Rh 免疫球蛋白（RhIg）的使用，RhD 免疫引起的胎儿和新生儿溶血病（HDFN）的风险大大降低，这是一种危及生命的潜在情况。通过检测母体血浆中的胎儿 RHD 可用于限制携带 RhD 阳性胎儿的妇女进行产前 RhIg 治疗，避免不必要地使用血液制品。
本研究旨在确定我们中心胎儿 RHD 分型的性能。我们前瞻性地收集了 205 例 RhD 阴性孕妇从妊娠 11 周（2019 年 10 月至 2021 年 10 月）开始的 205 例胎儿 RHD 和 127 例脐带血血清学 RhD 数据。使用靶向 RHD 外显子 5 和 7 的实时聚合酶链反应，类似于荷兰的筛查计划，辅以扩增对照（β-肌动蛋白；ACTB）和位于 Y 染色体上的性别决定标记（SRY 基因）。
胎儿 RHD 检测的灵敏度和特异性均达到 100%。未报告假阴性或假阳性结果。6%（13/205）的不确定结果是由于 10 例弱扩增、2 例母体 RHD 变异（RHD*01N.71 和部分 DVI）和 1 例胎儿 RHD 变异（部分 DVI）引起的。在 33%的情况下避免了不必要的 RhIg 预防治疗，另一方面，在 1 例（胎儿部分 DVI）中进行了预防治疗，如果仅进行脐带血血清学检查则可能会漏诊。
本研究表明，在妊娠 11 周后常规进行产前胎儿 RHD 基因筛查具有很高的准确性，鼓励常规临床实践。
