CONFERENCE--ISOLATED FETAL CELLS IN MATERNAL BLOOD

从母体血液中回收胎儿细胞的可能性已经很久了。 一直是对产前诊断感兴趣的遗传学家的目标。这将 将产前诊断（至少对于细胞遗传学疾病）扩展到 所有人，而不仅仅是那些风险增加的人。一九七九年， Hertzenberg及其同事使用流式分选技术恢复了 具有父亲而非母亲HLA-A2抗原的淋巴细胞，因此 可能是胎儿起源的。然而，相当多的怀疑 因为胎儿起源的确认是基于Y染色质 分析.经过近十年的表面上的不活动，几个团体， 最近使用聚合酶链反应（PCR）显示，胎儿 细胞很可能存在于母体血液中。第一组这样做的是 Lo等人的结果，他使用了Y序列的嵌套引物。妇女 事实证明，怀有男性胎儿的女性更有可能显示出Y染色体特异性信号， 比怀女性胎儿的人多。我们大学的候选细胞 田纳西小组以及其他人正在追求的是有核胎红 细胞（成红细胞）因此，我们采用荧光原位 用染色体特异性DNA探针进行荧光原位杂交（FISH）。在我们的一 第一次成功，在CVS之前采集血液样本并进行流式分选 显示18号染色体三体细胞。使用各种富集策略来分离 有核红细胞与FISH结合，其他人随后 也检测到胎儿非整倍体在这次会议上，我们将回顾 胎儿细胞复苏的科学基础和临床现状 应用程序.所有积极的工作人员寻求恢复各种细胞类型 将被邀请。我们将探讨这段经文背后的科学基础 胎儿细胞（滋养层细胞、淋巴细胞、有核红细胞）转化为 产妇的血液循环，流分类的科学依据和其他 富集技术，原位杂交的缺陷和潜力 进行诊断。以及临床前的道德和后勤要求 导论.会议开始时应概述 历史方面。接下来，我们将考虑胎盘的发育， 包括生理和解剖学的发展， 一种细胞类型与另一种细胞类型在胎儿循环中的传代。 母胎之间的免疫信号将被视为线索 用于解释母体血液中胎儿细胞的现象。当前 10-12个寻求恢复胎儿细胞的小组的工作状况将是 综述深入审议将集中在两个领域， 基本的进展对于临床应用来说是关键的。一个涉及 富集稀有细胞，即通过流式分选或磁性细胞 分居另一种是原位杂交技术，尤其是多基因原位杂交技术。 色彩技术然后，我们将考虑流的基础技术 分选，荧光探针的使用，最后，在 流式细胞仪检测流式细胞仪我们讨论的基础是 评估该技术在以下方面的灵敏度和特异性： 一般人口。总的来说，我们希望这次会议能更新当前的 在该领域的地位，帮助确定最有利可图的几个 潜在的方法，并允许制定合作研究， 将包括交换样本以确定灵敏度和特异性。

The possibility of recovering fetal cells from maternal blood has long been a goal for geneticists interested in prenatal diagnosis. This would extend prenatal diagnosis (at least for cytogenetic disorders) to the entire population, not merely those at increased risk. In 1979, Hertzenberg and colleagues used flow-sorting techniques to recover lymphocytes having a paternal but not maternal HLA-A2 antigen, thus presumably being fetal in origin. However, considerable skepticism persisted because confirmation of fetal origin was based on Y chromatin analysis. After nearly a decade of ostensible inactivity, several groups have recently used polymerase chain reaction (PCR) to show that fetal cells very likely exist in maternal blood. The first group to do so was that of Lo et al., who used nested primers for a Y sequence. Women carrying male fetuses proved far more likely to show a Y-specific signal than those carrying female fetuses. The candidate cell our University of Tennessee group as well as others are pursuing is the nucleated fetal red cell (erythroblast.) We thus are employing fluorescence in situ hybridization (FISH) with chromosome-specific DNA probes. In one of our first successes, a blood sample taken prior to CVS and flow-sorted revealed trisomy 18 cells. Using various enrichment strategies to isolate nucleated red cells in combination with FISH, others have subsequently detected fetal aneuploidies also. In this conference, we will review the scientific basis of fetal cell recovery, and current state of clinical application. All active workers seeking to recover the various cell types will be invited. We shall explore the scientific basis underlying passage of fetal cells (trophoblasts, lymphocytes, nucleated red blood cells) into the maternal circulation, the scientific basis of flow sorting and other enrichment techniques, the pitfalls and potential of in situ hybridization for diagnosis. and ethical and logistical requirements before clinical introduction. The conference shall begin with a general overview of historical aspects. Next, we shall consider placenta development, including physiological and anatomical developments that could favor passage in the fetal circulation of one cell type versus another. Immunologic signals between mother and fetus will be considered as a clue for explaining the phenomena of fetal cells in maternal blood. The current status of work by the 10-12 groups seeking to recover fetal cells will be reviewed. In-depth consideration will then focus on two areas in which fundamental advances appear pivotal to clinical application. One involves enrichment for rare cells, namely by either flow sorting or magnetic cell separation. The other is in situ hybridization (ISH), especially multi- color techniques. We will then consider basic technology underlying flow sorting, use of fluorescent probes and, finally, the application of in situ hybridization to flow sorted cells. Underlying our discussion will be assessment of the sensitivity and specificity of this technology in the general population. Overall, we expect this conference to update current status in the field, help identify the most profitable of several potential approaches and allow formulation of collaborative studies that will include exchange of samples to determine sensitivity and specificity.