Expression of CD56 is a risk factor for acute lymphocytic leukemia with central nervous system involvement in adults

<b>Objective:</b> To gain further insights into the predisposing risk factors for central nervous system (CNS) involvement in patients with acute lymphocytic leukemia (ALL), the impact of CD56 expression in these patients was investigated. <b>Methods:</b> We reviewed the clinical features of CD56 expression in 588 consecutive ALL patients treated with systemic chemotherapy regimens between 2000 and 2014. The categorical data from CD56⁺ ALL patients were compared with those from CD56⁻ ALL patients. <b>Results:</b> Among the 588 patients studied, 18.9% showed CD56 expression. The expression was significantly associated with CD33⁺, CD10⁻, CD15⁺, TdT⁻, and CD5⁺ immunophenotypes. After systemic chemotherapy, 8.8% patients showed CNS involvement, of which 3.2% exhibited combined recurrences and 5.6% exhibited isolated CNS involvement. The 5-year event-free survival was significantly lower for patients with CD56⁺ immunophenotype compared with patients with CD56⁻ immunophenotype (22.5% vs. 32.7%, <i>P</i> = 0.04). Cumulative incidences of CNS involvement were significantly greater in the CD56⁺ cohort compared with the CD56⁻ cohort (14.4% vs. 7.5%, <i>P</i> = 0.02). Multivariate analysis revealed CD56 expression to be statistically significant risk factors for CNS involvement. <b>Conclusion:</b> CD56 expression should be regarded as an independent risk factor for ALL with CNS involvement in adults.

<b>研究目的：</b>为进一步明确急性淋巴细胞白血病（acute lymphocytic leukemia, ALL）患者发生中枢神经系统（central nervous system, CNS）受累的易感危险因素，本研究针对该类患者的CD56表达影响展开了探究。
<b>研究方法：</b>我们回顾性分析了2000年至2014年间接受系统性化疗方案治疗的588例连续纳入的ALL患者的CD56表达相关临床特征，并将CD56阳性（CD56⁺）患者与CD56阴性（CD56⁻）患者的分类数据进行对比。
<b>研究结果：</b>在本次研究的588例患者中，18.9%的患者存在CD56表达。该表达与CD33阳性（CD33⁺）、CD10阴性（CD10⁻）、CD15阳性（CD15⁺）、TdT阴性（TdT⁻）及CD5阳性（CD5⁺）的免疫表型显著相关。经系统性化疗后，8.8%的患者出现中枢神经系统受累，其中3.2%为复发合并中枢神经系统受累，5.6%为单纯中枢神经系统受累。CD56阳性免疫表型患者的5年无事件生存率显著低于CD56阴性免疫表型患者（22.5% vs. 32.7%，<i>P</i> = 0.04）。CD56阳性队列的中枢神经系统受累累积发生率显著高于CD56阴性队列（14.4% vs. 7.5%，<i>P</i> = 0.02）。多因素分析显示，CD56表达是中枢神经系统受累的具有统计学意义的危险因素。
<b>研究结论：</b>CD56表达可被视为成人ALL患者合并中枢神经系统受累的独立危险因素。