Department of Radiation Oncology, Center for Radiological Research, Columbia University Irving Medical Center, New York, New York, USA.
Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York, USA.
Cytogenet Genome Res. 2023;163(3-4):121-130. doi: 10.1159/000534433. Epub 2023 Oct 4.
The cytokinesis-block micronucleus (CBMN) assay is an established method for assessing chromosome damage in human peripheral blood lymphocytes resulting from exposure to genotoxic agents such as ionizing radiation. The objective of this study was to measure cytogenetic DNA damage and hematology parameters in vivo based on MN frequency in peripheral blood lymphocytes (PBLs) from adult and pediatric leukemia patients undergoing hematopoietic stem cell transplantation preceded by total body irradiation (TBI) as part of the conditioning regimen. CBMN assay cultures were prepared from fresh blood samples collected before and at 4 and 24 h after the start of TBI, corresponding to doses of 1.25 Gy and 3.75 Gy, respectively. For both age groups, there was a significant increase in MN yields with increasing dose (p < 0.05) and dose-dependent decrease in the nuclear division index (NDI; p < 0.0001). In the pre-radiotherapy samples, there was a significantly higher NDI measured in the pediatric cohort compared to the adult due to an increase in the percentage of tri- and quadri-nucleated cells scored. Complete blood counts with differential recorded before and after TBI at the 24-h time point showed a rapid increase in neutrophil (p = 0.0001) and decrease in lymphocyte (p = 0.0006) counts, resulting in a highly elevated neutrophil-to-lymphocyte ratio (NLR) of 14.45 ± 1.85 after 3.75 Gy TBI (pre-exposure = 4.62 ± 0.49), indicating a strong systemic inflammatory response. Correlation of the hematological cell subset counts with cytogenetic damage, indicated that only the lymphocyte subset survival fraction (after TBI compared with before TBI) showed a negative correlation with increasing MN frequency from 0 to 1.25 Gy (r = -0.931; p = 0.007). Further, the data presented here indicate that the combination of CBMN assay endpoints (MN frequency and NDI values) and hematology parameters could be used to assess cytogenetic damage and early hematopoietic injury in the peripheral blood of leukemia patients, 24 h after TBI exposure.
细胞有丝分裂阻断微核（CBMN）试验是一种评估人类外周血淋巴细胞中染色体损伤的方法，这种损伤是由于接触到电离辐射等遗传毒性物质引起的。本研究的目的是通过外周血淋巴细胞（PBL）中的微核频率来测量细胞遗传学 DNA 损伤和血液学参数，这些 PBL 来自接受造血干细胞移植的成人和儿科白血病患者，移植前接受全身照射（TBI）作为预处理方案的一部分。CBMN 试验培养物是从 TBI 开始前和开始后 4 小时和 24 小时采集的新鲜血液样本中制备的，分别对应于 1.25 Gy 和 3.75 Gy 的剂量。对于两个年龄组，微核产量随着剂量的增加而显著增加（p < 0.05），核分裂指数（NDI）随着剂量的降低而呈剂量依赖性下降（p < 0.0001）。在放疗前样本中，儿科队列的 NDI 明显高于成人，这是由于三核和四核细胞的百分比增加所致。TBI 后 24 小时点进行的全血细胞计数和差异记录显示，中性粒细胞计数迅速增加（p = 0.0001），淋巴细胞计数减少（p = 0.0006），导致 3.75 Gy TBI 后中性粒细胞与淋巴细胞比值（NLR）升高至 14.45 ± 1.85（暴露前 NLR = 4.62 ± 0.49），表明强烈的全身炎症反应。血液细胞亚群计数与细胞遗传学损伤的相关性表明，只有淋巴细胞亚群存活率（TBI后与 TBI 前相比）与 0 至 1.25 Gy 之间微核频率的增加呈负相关（r = -0.931；p = 0.007）。此外，本文提供的数据表明，CBMN 试验终点（微核频率和 NDI 值）和血液学参数的组合可用于评估白血病患者 TBI 暴露后 24 小时外周血中的细胞遗传学损伤和早期造血损伤。
