Prognostic Significance of CD45dimCD117+ Cells in Patients with Acute Myeloid Leukemia after Complete Remission

Abstract

To investigate the predictive value of CD45dimCD117+ phenotype-abnormal cells (hereinafter referred to as "abnormal cells") for relapse and prognosis in adult patients with acute myeloid leukemia (AML) within 2 weeks after the first complete remission (CR1). The clinical data of patients with newly diagnosed AML (non-acute promyelocytic leukemia) admitted in our department from July 1, 2014 to June 30, 2017 were analyzed retrospectively, and the relationship between clinical features at the initial diagnosis and the abnormal phenotype cells of CD45dimCD117+ within 2 weeks after CR1 with the prognosis were analyzed. A total of 91 patients with CD45dimCD117+ abnormal cells were detected. The median age was 51 years old, the median WBC count was 11.60×109/L, and the median ratio of bone marrow blast cells was 0.35 at initial diagnosis. According to the FAB classification, 1 (1.1%), 7 (7.7%), 38 (41.7%), 20 (22.0%), 21 (23.1%) and 4 (4.4%) patients were classifice as M0, M1, M2, M4, M5, and M6, respectively. According to the NCCN risk stratification, 30 (33.0%), 51 (56.0%), and 10 (11.0%) patients were determined as good, moderate, and poor prognosis, respectively. The median ratio of abnormal cells within 2 weeks after CR1 was 1.8500 (0.0236-8.0000)%. The median time from initiation of induction therapy to the acquisition of CR was 46 days, median recurrence-free survival time was 319 days, and median overall survival time was 352 days. A total of 45 patients relapsed, of which 14 died; 46 patients did not relapse, of which 3 died. The cutoff of abnormal cells by receiver operating characteristic curve (ROC) analysis was 2.055% (Se=0.733，Sp=0.761). The abnormal cell ratio was＞2.055% in 44 patients, the median ratio of abnormal cells was 3.075%, among which 33 patients relapsed and 12 patients died; the abnormal cell ratio was ＜2.055% in 47 patients, the median ratio of abnormal cells was 1.150%, 12 patients relapsed and 5 patients died. Regression analysis showed that WBC count＞50×109/L and abnormal cell ratio＞2.055% were independent risk factors for recurrence. The abnormal cell ratio＞2.055% group had a 2-year RFS rate of 54.3% and a 2-year OS rate of 52.8%. The abnormal cell ratio＜2.055% group had a 2-year RFS rate of 86.6% (P=0.018), and a 2-year OS rate of 85.3% (P＜0.05). For adult AML patients, CD45dimCD117+ phenotypical abnormal cells ratio＞2.055% within 2 weeks after CR1 is an independent risk factor for recurrence, which also is an dverse factor for RFS and OS.