急性髓系白血病（AML）和高白细胞计数对预后不利，但儿童AML患者高白细胞计数对预后的影响尚不确定。我们调查了儿童AML伴高白细胞计数的临床特征和预后，定义高白细胞计数为WBC≥50×109/L。从2009年9月至2021年8月，我们连续纳入132例新诊断的儿童AML伴高白细胞计数的患者，以调查预后因素和临床结果。高白细胞计数发生在27.4%的AML患者中。儿童患者伴高白细胞计数的CR和OS率与无高白细胞计数的患者相似，但EFS率较低。在我们的研究中，WBC计数为50-100×109/L和≥100×109/L的AML患者的CR1率、死亡率、复发/难治性疾病率和造血干细胞移植率相似。WBC计数为50-100×109/L的AML患者的5年OS率与WBC计数≥100×109/L的患者相似（74.6%与75.4%，P=0.921）。在所有伴高白细胞计数的患者中，FAB M5亚型与明显较差的生存率有关，而CBF-AML的预后良好。儿童AML患者伴高白细胞计数不论其WBC计数为50-100×109/L还是≥100×109/L，预后相似。©2023年日本血液学会。

Acute myeloid leukemia (AML) and hyperleukocytosis have an unfavorable prognosis, but the impact of hyperleukocytosis on the prognosis of pediatric AML remains uncertain. We investigated the clinical characteristics and prognosis of pediatric AML with hyperleukocytosis, defined as WBC ≥ 50 × 109/L.A total of 132 patients with newly diagnosed childhood AML with hyperleukocytosis were consecutively enrolled at our center from September 2009 to August 2021 to investigate prognostic factors and clinical outcomes.Hyperleukocytosis occurred in 27.4% of AML patients. Pediatric patients with hyperleukocytosis had similar CR and OS rates to those without hyperleukocytosis, but had a lower EFS rate. In our study, rates of CR1, mortality, relapsed/refractory disease, and HSCT were comparable between AML patients with WBC counts of 50-100 × 109/L and ≥ 100 × 109/L. AML patients with a WBC count of 50-100 × 109/L had a similar 5-year OS rate to patients with a WBC count ≥ 100 × 109/L (74.6% vs. 75.4%, P = 0.921). Among all patients with hyperleukocytosis, the FAB M5 subtype was associated with significantly inferior survival, and the prognosis of CBF-AML was good.Pediatric AML patients with hyperleukocytosis have the similar prognosis regardless of whether their WBC count is 50-100 × 109/L or ≥ 100 × 109/L.© 2023. Japanese Society of Hematology.