Ludescher C, Eisterer W, Hilbe W, Gotwald M, Hofmann J, Zabernigg A, Cianfriglia M, Thaler J
Department of Internal Medicine, University of Innsbruck, Austria.
Leukemia. 1995 Feb;9(2):350-6.
The purpose of our investigations was to measure P-glycoprotein (P-170) activity in blast cells of 35 adults with acute myeloid leukemia (AML), and 24 children and adults with acute lymphoblastic leukemia (ALL) at time of diagnosis. Studies were based on a flow cytometric assay that detects efflux of the fluorescent dye rhodamine 123 (Rh123), which is transported from the cell by the P-170 pump. Dual-fluorescence staining with Rh123 and phycoerythrin-labeled monoclonal antibodies allowed selective measurement of Rh123 efflux in blast cells. Samples were scored positive when the fraction of blast cells showing Rh123 efflux exceeded 10% after a 120-min incubation. Activity of P-170 was observed in 19 (54%) of the 35 AML cases and was completely blocked in the presence of multidrug resistance inhibitors. Efflux activity was significantly higher in CD34-positive AML samples (p < 0.02). All AML patients with the FAB-subtype M5 (n = 5) lacked Rh123 pumping activity (p < 0.03). The complete remission rate in response to induction chemotherapy was significantly higher for Rh123-negative (11/13, 85%) than for Rh 123-positive AML patients (4/15, 27%) (p < 0.007). At a median follow-up of 9 months overall survival was significantly shorter for Rh123-positive than for Rh123-negative patients (p < 0.05). In contrast to AML, we could detect Rh123 efflux in only two (8%) out of 24 ALL cases. The immunological subtypes of these two positive cases was of B-ALL and pre-T-ALL. Bone marrow cryostat sections from 13 AML and five ALL patients were further analyzed for staining with monoclonal antibodies MM4.17 and JSB1. Ten of 13 AML and two of five ALL cases expressed the MDR protein. Our results indicate that there is a rather low frequency of P-170 pumping activity in ALL compared with AML. Further, functional activity of P-170 contributes to chemoresistance in de novo AML.
我们研究的目的是测定35例成年急性髓系白血病（AML）患者以及24例儿童和成年急性淋巴细胞白血病（ALL）患者诊断时原始细胞中的P-糖蛋白（P-170）活性。研究基于一种流式细胞术检测方法，该方法可检测荧光染料罗丹明123（Rh123）的外排情况，Rh123由P-170泵从细胞中转运出去。用Rh123和藻红蛋白标记的单克隆抗体进行双荧光染色，可选择性地测定原始细胞中Rh123的外排情况。孵育120分钟后，若显示Rh123外排的原始细胞比例超过10%，则样本被判定为阳性。在35例AML病例中，有19例（54%）观察到P-170活性，且在多药耐药抑制剂存在的情况下活性被完全阻断。CD34阳性的AML样本中外排活性显著更高（p < 0.02）。所有FAB亚型为M5的AML患者（n = 5）均缺乏Rh123泵活性（p < 0.03）。诱导化疗后，Rh123阴性的AML患者（11/13，85%）完全缓解率显著高于Rh123阳性的AML患者（4/15，27%）（p < 0.007）。在中位随访9个月时，Rh123阳性患者的总生存期显著短于Rh123阴性患者（p < 0.05）。与AML相反，在24例ALL病例中，我们仅在2例（8%）中检测到Rh123外排。这两例阳性病例的免疫亚型为B-ALL和前T-ALL。对13例AML患者和5例ALL患者的骨髓低温切片用单克隆抗体MM4.17和JSB1进行进一步染色分析。13例AML患者中有10例以及5例ALL患者中有2例表达多药耐药蛋白。我们的结果表明，与AML相比，ALL中P-170泵活性的频率相当低。此外，P-170的功能活性导致初发AML的化疗耐药。
