Lion T, Gaiger A, Henn T, Hörth E, Haas O A, Geissler K, Gadner H
Children's Cancer Research Institute, St Anna Children's Hospital, Vienna, Austria.
Leukemia. 1995 Aug;9(8):1353-60.
Interferon-alpha (IFN-alpha) has become a widely used treatment modality in chronic myelogenous leukemia (CML) and was shown to induce complete hematologic responses in about 70% of the patients. In a minority of cases, complete suppression of the Philadelphia (Ph)-positive clone has been observed by cytogenetic investigation or by Southern blot analysis. In most instances, however, analyses by the highly sensitive two-step polymerase chain reaction (PCR) reveal the presence of residual leukemic cells despite continuous treatment. Since PCR positivity has not been associated with an increased risk of disease recurrence, the monitoring of cells carrying the characteristic BCR/ABL rearrangement by qualitative PCR may not facilitate early identification of patients who are likely to relapse. We have therefore employed a quantitative PCR technique to monitor the BCR/ABL mRNA expression levels during the course of treatment in an attempt to assess the response to IFN-alpha at the molecular level and to provide a basis for early detection of progressive disease. Twenty CML patients who received therapy with IFN-alpha in first chronic phase of the disease were enrolled in the study. In addition, we have monitored two CML patients treated with IFN-alpha for relapse after bone marrow transplantation. Thirteen patients who displayed decreasing, constant or fluctuating levels of BCR/ABL expression during an observation period of up to 4 years (mean 25 months) have remained in hematologic remission. Two patients showed an elevation in the marker gene expression upon discontinuation of treatment, but no further increase in BCR/ABL mRNA has been observed after reinitiation of therapy with IFN, and the patients have remained in hematologic remission. In seven patients, quantitative PCR (Q-PCR) analyses revealed increasing expression of the chimeric gene during treatment with IFN-alpha. In all seven cases, the detection of elevated BCR/ABL transcripts by quantitative PCR preceded signs of hematologic or cytogenetic disease progression by up to 8 months (median 6 months). Our data show that quantitative PCR analysis facilitates the monitoring of the response to IFN-alpha therapy and provides an effective diagnostic tool for the timely detection of recurrent disease. The employment of this technique greatly enhances the diagnostic possibilities in the management of chronic myelogenous leukemia.
α干扰素（IFN-α）已成为慢性粒细胞白血病（CML）中广泛使用的治疗方式，并且已证明其可使约70%的患者产生完全血液学反应。在少数病例中，通过细胞遗传学研究或Southern印迹分析观察到费城（Ph）阳性克隆被完全抑制。然而，在大多数情况下，尽管持续治疗，通过高度敏感的两步聚合酶链反应（PCR）分析仍可发现残留白血病细胞的存在。由于PCR阳性与疾病复发风险增加无关，因此通过定性PCR监测携带特征性BCR/ABL重排的细胞可能无法促进对可能复发患者的早期识别。因此，我们采用定量PCR技术来监测治疗过程中BCR/ABL mRNA的表达水平，以试图在分子水平评估对IFN-α的反应，并为早期发现疾病进展提供依据。20例处于疾病第一慢性期且接受IFN-α治疗的CML患者被纳入该研究。此外，我们还监测了2例接受IFN-α治疗以预防骨髓移植后复发的CML患者。在长达4年（平均25个月）的观察期内，13例BCR/ABL表达水平呈下降、稳定或波动的患者一直处于血液学缓解状态。2例患者在停药后标记基因表达升高，但在重新使用IFN治疗后未观察到BCR/ABL mRNA进一步增加，且这些患者一直处于血液学缓解状态。在7例患者中，定量PCR（Q-PCR）分析显示在IFN-α治疗期间嵌合基因表达增加。在所有7例病例中，通过定量PCR检测到BCR/ABL转录本升高比血液学或细胞遗传学疾病进展迹象提前长达8个月（中位数6个月）。我们的数据表明，定量PCR分析有助于监测对IFN-α治疗的反应，并为及时检测复发性疾病提供有效的诊断工具。该技术的应用极大地提高了慢性粒细胞白血病管理中的诊断可能性。
