实时定量RT-PCR监测慢性粒细胞白血病患者伊马替尼治疗过程中bcr/abl mRNA水平

Monitoring bcr/abl mRNA levels in imatinib mesylate treated chronic myeloid leukemia patients by real-time quantitative RT-PCR

目的观察甲磺酸伊马替尼(简称伊马替尼)治疗Ph+慢性粒细胞白血病(CML)患者骨髓bcr/ablmRNA水平的变化。方法采用实时定量(Realtimequantitative)RTPCR(RQPCR)技术连续监测34例α干扰素治疗无效Ph+CML患者在伊马替尼治疗前后不同时间120份骨髓标本bcr/ablmRNA水平。治疗前骨髓Ph+细胞百分率均≥95%。结果RQPCR的敏感度为10pgRNA,标准品日间差及日内差均<5%。10例伊马替尼治疗前标本中位bcr/ablmRNA水平为5.79%,各例之间差异甚大(0.24%～60.90%)。72份Ph+细胞百分率为0%～94%的治疗后标本bcr/ablmRNA水平与Ph+细胞百分率显著相关(r=0.82,P<0.001)。7例治疗12个月内达到完全遗传学缓解(CCyR)的患者bcr/ablmRNA水平随治疗时间延长而迅速降低,可供分析的6例患者治疗3个月时较治疗前下降65.9%～98.8%。达到CCyR后,bcr/ablmRNA水平随治疗时间延长继续下降,直至为0。4例治疗12个月后获得显著遗传学缓解患者(Ph+细胞百分率均<35%)bcr/ablmRNA水平缓慢下降,可供分析的3例患者治疗3个月时的bcr/ablmRNA水平分别比治疗前下降2.5%、18.5%及61.6%。5例持续遗传学无效,并且维持在慢性期的患者bcr/ablmRNA水平1例缓慢下降,2例缓慢上升,2例基本不变。4例治疗中发生急变的患者bcr/ablmRNA水平均逐步升高。

Objective To quantify bone marrow bcr/abl mRNA levels in imatinib mesylate treated Ph chromosome positive chronic myeloid leukemia (CML) patients. Methods Serial monitoring of bcr/abl mRNA levels by real-time quantitative RT-PCR technique (RQ-PCR) was performed in 34 cases (120 samples) of CML treated with imatinib mesylate. All the patients were IFNα based treatment failure before enrolled in this study and the percentage of Ph+ bone marrow cells were over 95%. Results The sensitivity of RQ-PCR was 10 pg RNA, with both coefficients of interassay and intraassay variation below 5% for standard samples. The median bcr/abl mRNA level of 10 patients’s amples pre imatinib treatment was 5.79% with marked variation (0.24%—60.90%). In 72 samples post imatinib treatment, which the rates of Ph+ cells [Ph(+)%] were between 0 and 94%, the mRNA level well correlated with Ph(+)% (r=0.82,P<~0.001 ). The mRNA levels of 7 patients who achieved complete cytogenetic response (CCyR) within 12 months decreased markedly, the levels of 6 analysable patients decreased by 65.9%—98.8% after 3 months’treatment accordingly. The level further decreased to 0 after achieving CCyR. For 4 patients who achieved major cytogenetic response (Ph+ cells<35%) later than 12 months, the mRNA levels decreased slowly.The levels of 3 analysable patients on 3 month therapy decreased by 2.5%, 18.5% and 61.6% compared with that before treatment. Out of 5 patients in chronic phase without cytogenetic response, 1 decreased, 2 increased gradually and 2 had no change. In 4 disease progression patients, the levels increased stepwise. Conclusions Serial quantifications of bcr/abl mRNA levels are necessary for imatinib treated patients, and are more informative than a single detection. A sharp decline of bcr/abl mRNA levels after the treatment implies a promise of CCyR.