Pichert G, Alyea E P, Soiffer R J, Roy D C, Ritz J
Division of Hematologic Malignancies, Dana-Farber Cancer Institute, Boston, MA 02115.
Blood. 1994 Oct 1;84(7):2109-14.
Previous studies have shown that tumor-specific bcr-abl mRNA can often be detected by polymerase chain reaction. (PCR) for months to years after allogeneic bone marrow transplantation (BMT) for chronic myelocytic leukemia (CML). Nevertheless, the presence of bcr-abl mRNA by itself does not invariably predict for clinical relapse post-BMT. This has led to the hypothesis that bcr-abl mRNA might be expressed in cells that have lost either proliferative or myeloid differentiation potential. To directly characterize the cells detected by PCR in patients with CML after allogeneic BMT, we first identified five individuals in whom PCR-positive cells could be detected at multiple times post-BMT. Bone marrow samples from these individuals were cultured in vitro and single erythroid, granulocytic, and macrophage colonies, each containing 50 to 100 cells, were examined for the presence of bcr-abl mRNA by PCR. PCR-positive myeloid colonies could be detected in four of five individuals in marrow samples obtained 5 to 56 months post-BMT. Overall, 7 of 135 progenitor cell colonies (5.2%) were found to be PCR-positive. The expression of bcr-abl mRNA appeared to be equally distributed among committed erythroid, macrophage, and granulocyte progenitors. These patients have now been followed-up for an additional 20 to 33 months from the time of progenitor cell PCR analysis but only one of these individuals has been found to have cytogenetic evidence of recurrent Ph+ cells. These results show that long-term persistence of PCR-detectable bcr-abl mRNA after allogeneic BMT can be caused by the persistence of CML-derived clonogenic myeloid precursors that have survived the BMT preparative regimen. These cells continue to have both proliferative and myeloid differentiation capacity in vitro. Nevertheless, these PCR-positive cells do not appear to either expand or differentiate in vivo for prolonged periods, suggesting the presence of mechanisms for suppression of residual clonogenic leukemia cells in vivo.
先前的研究表明，在慢性粒细胞白血病（CML）患者接受异基因骨髓移植（BMT）后的数月至数年里，通常可通过聚合酶链反应（PCR）检测到肿瘤特异性的bcr-abl mRNA。然而，bcr-abl mRNA的存在本身并不能始终预测BMT后的临床复发。这就引发了一个假说，即bcr-abl mRNA可能在那些已丧失增殖或髓系分化潜能的细胞中表达。为了直接鉴定异基因BMT后CML患者中通过PCR检测到的细胞，我们首先确定了五名个体，在BMT后的多个时间点都能检测到PCR阳性细胞。从这些个体获取的骨髓样本在体外进行培养，然后通过PCR检测每个含有50至100个细胞的单个红系、粒系和巨噬细胞集落中bcr-abl mRNA的存在情况。在BMT后5至56个月获取的骨髓样本中，五名个体中有四名检测到了PCR阳性的髓系集落。总体而言，135个祖细胞集落中有7个（5.2%）被发现为PCR阳性。bcr-abl mRNA的表达似乎在定向红系、巨噬细胞和粒系祖细胞中均匀分布。从祖细胞PCR分析之时起，这些患者现已又随访了20至33个月，但其中只有一名个体被发现有复发的Ph+细胞的细胞遗传学证据。这些结果表明，异基因BMT后PCR可检测到的bcr-abl mRNA的长期持续存在可能是由于CML来源的具有克隆形成能力的髓系前体细胞在BMT预处理方案中存活下来所致。这些细胞在体外继续具有增殖和髓系分化能力。然而，这些PCR阳性细胞在体内似乎并不会长时间扩增或分化，这表明体内存在抑制残留克隆形成白血病细胞的机制。
