Stewart A K, Imrie K, Keating A, Anania S, Nayar R, Sutherland D R
University of Toronto Autologous Blood and Marrow Transplantation Program and Oncology Research, Toronto Hospital, Ontario, Canada.
Exp Hematol. 1995 Dec;23(14):1619-27.
We have previously described a sensitive and specific CD34 enumeration assay and report here a prospective analysis of 25 myeloma patients undergoing PBSC mobilization using this assay to determine the optimal days for collection of CD34+ and CD34+Thy-1+ cells after chemotherapy and growth factor mobilization. Correlations between frequency of peripheral blood CD34+ cells, circulating white blood cell (WBC) count, apheresis CD34+ cell count, nucleated cell count (NCC), and numbers of apheresis colony-forming units granulocyte/macrophage (CFU-GM) were determined. To assess levels of the more primitive subsets of CD34+ cells in the PBSC collections, coexpression of the Thy-1 antigen (CDw90) on CD34+ cells was also assessed. Marked heterogeneity was noted between patients with apheresis samples containing a median NCC of 4.2 x 10(8)/kg (range 1.3-8.1), median CFU-GM 17 x 10(4)/kg (range 0.15-32 x 10(4)/kg), and median CD34+ cell count of 1.39 x 10(6)/kg (range 0.02-6.6). The frequency of CD34+ cells in PBSC collections coexpressing Thy-1 was also heterogenous (6.2-50% of CD34+ cells), median 21.6%, mean 24.7 +/- 2%. The apheresis CD34+ cell count correlated with the peripheral blood CD34+ cell percentage (r = 0.71, p < 0.0001) but only weakly with the peripheral WBC. Apheresis CD34+Thy-1+ cell numbers correlated strongly with the circulating CD34+ cell numbers (r = 0.80), but no correlation was noted between these candidate stem cells and the peripheral WBC. In contrast, apheresis CFU-GM levels correlated most strongly with the peripheral WBC count (r = 0.61, p < 0.0001). The apheresis CD34+ cell count correlated with apheresis CFU-GM (r = 0.75, p < 0.0001) but not with the apheresis NCC. Apheresis CD34+Thy-1+ counts significantly correlated only with the apheresis CD34+ cell count and not with the apheresis CFU-GM or NCC. A higher percentage of circulating and apheresis CD34+ cells expressing Thy-1 were found on day 1 of collection, and the percentage of CD34+ cells expressing Thy-1 decreased on each subsequent day of measurement: median of 22% day 1 vs. 16.6% day 4, p = 0.04. This study therefore confirms that accurate quantitation of circulating CD34+ cells best predicts the optimal day for apheresis collection of CD34+ and CD34+Thy-1+ cells and is superior to the WBC count in this regard. Furthermore, the candidate stem cell (CD34+Thy-1+) subset is most prevalent during the earliest phases of CD34+ cell mobilization.
我们之前描述过一种灵敏且特异的CD34计数检测方法，在此报告一项对25例接受外周血干细胞（PBSC）动员的骨髓瘤患者的前瞻性分析，该分析使用此检测方法来确定化疗和生长因子动员后采集CD34+和CD34+Thy-1+细胞的最佳天数。测定了外周血CD34+细胞频率、循环白细胞（WBC）计数、单采CD34+细胞计数、有核细胞计数（NCC）以及单采集落形成单位粒细胞/巨噬细胞（CFU-GM）数量之间的相关性。为评估PBSC采集中更原始的CD34+细胞亚群水平，还评估了CD34+细胞上Thy-1抗原（CDw90）的共表达情况。单采样本中，患者之间存在显著异质性，其中位NCC为4.2×10⁸/kg（范围1.3 - 8.1），中位CFU-GM为17×10⁴/kg（范围0.15 - 32×10⁴/kg），中位CD34+细胞计数为1.39×10⁶/kg（范围0.02 - 6.6）。PBSC采集中共表达Thy-1的CD34+细胞频率也存在异质性（占CD34+细胞的6.2% - 50%），中位值为21.6%，均值为24.7±2%。单采CD34+细胞计数与外周血CD34+细胞百分比相关（r = 0.71，p < 0.0001），但与外周WBC的相关性较弱。单采CD34+Thy-1+细胞数量与循环CD34+细胞数量密切相关（r = 0.80），但这些候选干细胞与外周WBC之间未发现相关性。相比之下，单采CFU-GM水平与外周WBC计数的相关性最强（r = 0.61，p < 0.0001）。单采CD34+细胞计数与单采CFU-GM相关（r = 0.75，p < 0.0001），但与单采NCC无关。单采CD34+Thy-1+计数仅与单采CD34+细胞计数显著相关，与单采CFU-GM或NCC无关。在采集第1天发现循环和单采CD34+细胞中表达Thy-1的比例更高，且在随后各测量日表达Thy-1的CD34+细胞比例均下降：第1天中位值为22%，第4天为16.6%，p = 0.04。因此，本研究证实，准确定量循环CD34+细胞最能预测单采采集CD34+和CD34+Thy-1+细胞的最佳天数，在这方面优于WBC计数。此外，候选干细胞（CD34+Thy-1+）亚群在CD34+细胞动员的最早阶段最为普遍。
