- 期刊
羊水培養無法排除母體細胞污染之案例報告
Case Report: Maternal Cell Contamination in Amniocytic Cell Culture
摘要
羊水為產前診斷重症甲型海洋性貧血的主要檢體來源，故一般實驗室會將羊水檢體經細胞培養，去除母體細胞污染源。在此，我們在此報告一罕見胎兒羊水案例，此例經細胞培養後，仍無法去除母體細胞污染，需輔以其他實驗方法加以確認正確胎兒基因型。本案例胎兒檢體第一次送檢為絨毛膜細胞（CV），以傳統PCR診斷，結果為Southeast Asia type （SEA）為陰性，但即時PCR（Real-time PCR）及短序列重覆片段聚合脢連鎖反應（STR PCR）皆發現有少許母體細胞污染。為求正確產前診斷，實驗室要求以羊水檢體複檢，根據上述方法，培養前羊水結果為SEA type陰性；然而，培養後之羊水卻為陽性。再以STR PCR分析此胎兒不同檢體發現，CV與培養前羊水之胎兒性別為男性；但培養後之羊水性別為女性，且STR PCR亦發現母體DNA存在。再者，觀察培養後羊水細胞型態，發現其細胞形態較扁大，非呈現胎兒羊水細胞常見的細長紡錘狀。根據上述結果，猜測應為羊水培養時，母體細胞與胎兒細胞共同繁殖，造成培養前後羊水的基因診斷結果及細胞型態有異。因此，為避免產前診斷SEA type的誤差，除細胞培養去除母體細胞污染外，建議輔以即時、STR PCR與細胞型態，作為輔助診斷，避免胎兒基因的錯誤診斷。
並列摘要
The amniotic fluid cells have being used as the major source of prenatal diagnosis of alpha thalassemia major. To avoid the contamination form mother cells, amniotic fluid culture was usually performed in routine laboratories before diagnosis. Here we presented a rare case of mother amniocyte cells contamination during diagnosis. After cell culture, the fetal cultured amniocytes were still found contaminated by mother cells. Thus other supplementary methods had to be performed for final confirmation of the fetus genotype. The first fetal specimen analysed was the chorionic villi (CV). Traditional PCR analysis indicated Southeast Asia type (SEA) negative. However, real-time PCR and short tandem repeat (STR) PCR analysis indicated contamination of traces of mother cells. To further clarify the results, the specimen of amniotic fluid was subsequently used. Similarly, samples were SEA type negative before culture; however, results turned positive after culture. Further, STR PCR analysis of different specimens from the fetus indicated a male fetus before cell culture of CV and uncultured amniocytes. Intriguingly, the gender turned female after cultured amniotic fluid. Coincidentally, existence of mother cells was detected. Cell morphology of mother amniotic fluid cells is comparatively larger than the fibroblast-like fetal amniocytes. Based on the results obtained, it was hypothesized that both mother sand fetus cells proliferate at the same time during amniotic fluid culture, resulting in inconsistence of the diagnostic results. To avoid diagnostic errors, besides cell culture to get rid of mother cell contamination, real-time PCR and STR PCR were suggested as supportive approaches.