Imudia Anthony N, Suzuki Yoko, Kilburn Brian A, Yelian Frank D, Diamond Michael P, Romero Roberto, Armant D Randall
Department of Obstetrics & Gynecology, Wayne State University School of Medicine, Detroit, MI, USA.
Hum Reprod. 2009 Sep;24(9):2086-92. doi: 10.1093/humrep/dep206. Epub 2009 Jun 4.
Fetal cells are shed from the regressing chorionic villi and it is possible to retrieve extravillous cytotrophoblast cells by transcervical sampling. The abundance of trophoblast cells in transcervical samples suggests that this non-invasive approach could distinguish between normal and abnormal pregnancies, such as an ectopic pregnancy (EP) and blighted ovum (BO). We aim to identify and quantify fetal trophoblast cells in the cervical canal during the first trimester to assess their usefulness to predict an abnormal pregnancy.
Patients, age 18-45, presenting with a normal intrauterine pregnancy (IUP; n = 37), diagnosis of EP (n = 10) or BO (n = 5) were enrolled for collection of transcervical specimens using a cytobrush and fixative rinse. Non-pregnant, nulliparous women (n = 7) were included as negative controls. Cells were cleared of mucus by acidification, prepared on microscope slides and labeled with a monoclonal antibody recognizing the trophoblast marker, human leukocyte antigen (HLA)-G. HLA-G positive and negative cells were counted to calculate the ratio of trophoblast cells to total cervical cells.
Trophoblast cells were observed in 35/37 normal IUP, 6/10 EP and 4/5 BO specimens. The average frequency of HLA-G positive cells in the normal IUP cervical samples was approximately 1 in 2000, which was 4-fold higher than samples from patients with EP or BO (P < 0.001). Receiver operating characteristic analysis showed that EP and BO pregnancies were distinguishable from normal pregnancies with 93% sensitivity, 95% specificity, 97% positive predictive value and 87% negative predictive value.
This pilot study presents evidence that trophoblast cells can be reliably obtained and identified among cervical cells in the first trimester by immunohistochemical staining for HLA-G, and suggests for the first time that abnormal pregnancies may be predictable based on the abundance of trophoblast cells in the cervical canal.
胎儿细胞从退化的绒毛膜绒毛中脱落，通过经宫颈采样有可能获取绒毛外细胞滋养层细胞。经宫颈样本中滋养层细胞数量丰富，这表明这种非侵入性方法可区分正常与异常妊娠，如异位妊娠（EP）和枯萎卵（BO）。我们旨在识别并量化孕早期宫颈管内的胎儿滋养层细胞，以评估其预测异常妊娠的效用。
纳入年龄在18至45岁之间、有正常宫内妊娠（IUP；n = 37）、诊断为EP（n = 10）或BO（n = 5）的患者，使用细胞刷和固定剂冲洗收集经宫颈标本。纳入未孕、未生育的女性（n = 7）作为阴性对照。通过酸化去除细胞上的黏液，制备在载玻片上，并用识别滋养层标志物人类白细胞抗原（HLA）-G的单克隆抗体进行标记。对HLA-G阳性和阴性细胞进行计数，以计算滋养层细胞与宫颈总细胞的比例。
在35/37例正常IUP、6/10例EP和4/5例BO标本中观察到滋养层细胞。正常IUP宫颈样本中HLA-G阳性细胞的平均频率约为2000个中有1个，这比EP或BO患者的样本高4倍（P < 0.001）。受试者操作特征分析表明，EP和BO妊娠与正常妊娠可区分，灵敏度为93%，特异度为95%，阳性预测值为97%，阴性预测值为87%。
这项初步研究表明，通过对HLA-G进行免疫组织化学染色，在孕早期宫颈细胞中可可靠地获取并识别滋养层细胞，首次提示基于宫颈管内滋养层细胞的数量可能预测异常妊娠。
