Nizet Y, Van Daele S, Lewalle P, Vaerman J L, Philippe M, Vermylen C, Cornu G, Ferrant A, Michaux J L, Martiat P
Department of Hematology, Cliniques Universitaires Saint-Luc, Brussels, Belgium.
Blood. 1993 Sep 1;82(5):1618-25.
We sequentially studied bone marrow (BM) samples of 25 patients in complete remission of an acute lymphoblastic leukemia (ALL) using a simplified polymerase chain reaction (PCR) strategy (direct use of the PCR product as a clonogenic probe recognizing rearranged Ig heavy chain sequences) as a first approach. BM aspirates were serially investigated after obtention of a complete response. When sensitivity was less than 1:10(4), the PCR fragment was sequenced and a specific oligonucleotide was synthetized and used as a probe (five cases). Cases in which minimal residual disease (MRD) became undetectable were cross-controlled using either TCR delta rearrangement or a specific translocation to circumvent the problem of false-negative results arising from clonal evolution. The median follow-up was 30 months (3 to 51 months). Within the first 3 months of complete remission, MRD was detectable in 22 of 23 investigated patients and remained so in 19 of 21 patients examined at 6 months, regardless of the long-term clinical outcome. In patients remaining in complete remission at 30 months or more, two patterns of MRD emerged during the follow-up. Either it continuously decreased to ultimately become undetectable (five patients) or remained detectable (five patients) with an increase after discontinuation of treatment in two. In the eight patients who relapsed, MRD persisted throughout the clinical course, and eventually increased 3 to 12 months before relapse was clinically detectable. In one case, clonal evolution of the VDJ heavy chain region was observed and recurrence of MRD shown by the use of TCR delta rearrangement as a control. We conclude that the use of this simplified methodology is a valuable tool for the follow-up of MRD in a majority of ALL patients, though in a few cases, sequencing needs to be performed to achieve a relevant sensitivity. The possibility of clonal evolution requires a cross-control of any sample becoming negative whatever the initial rearrangement used to generate a probe. In patients on therapy, sequential search for MRD seems to be a good tool for predicting the long-term outcome. In addition, patients remaining positive at the time treatment is discontinued or with a high tumor burden after a few months therapy may be at a higher risk of subsequent relapse, although a longer follow-up is needed to answer this question.
我们采用简化的聚合酶链反应（PCR）策略（直接将PCR产物用作识别重排Ig重链序列的克隆探针），作为首要方法，对25例急性淋巴细胞白血病（ALL）完全缓解患者的骨髓（BM）样本进行了序贯研究。在获得完全缓解后，对骨髓抽吸物进行了连续检测。当灵敏度低于1:10⁴时，对PCR片段进行测序，并合成特异性寡核苷酸用作探针（5例）。对于微小残留病（MRD）检测不到的病例，使用TCRδ重排或特异性易位进行交叉对照，以规避因克隆进化导致假阴性结果的问题。中位随访时间为30个月（3至51个月）。在完全缓解的前3个月内，23例接受检测的患者中有22例可检测到MRD，在6个月时接受检查的21例患者中有19例仍可检测到MRD，无论长期临床结局如何。在30个月或更长时间保持完全缓解的患者中，随访期间出现了两种MRD模式。要么它持续下降最终检测不到（5例患者），要么保持可检测（5例患者），其中2例在治疗中断后有所增加。在8例复发的患者中，MRD在整个临床过程中持续存在，并最终在临床可检测到复发前3至12个月增加。在1例患者中，观察到VDJ重链区域的克隆进化，并通过使用TCRδ重排作为对照显示了MRD的复发。我们得出结论，使用这种简化方法是大多数ALL患者MRD随访的有价值工具，尽管在少数情况下，需要进行测序以达到相关灵敏度。克隆进化的可能性要求对任何变为阴性的样本进行交叉对照，无论最初用于生成探针的重排是什么。在接受治疗的患者中，序贯检测MRD似乎是预测长期结局的良好工具。此外，在治疗中断时仍为阳性或在几个月治疗后肿瘤负荷较高的患者，后续复发风险可能更高，尽管需要更长时间的随访来回答这个问题。
