Objective:To investigate the clinical features and prognostic factors of pediatric patients with acute hyperleukocytic leukemia (AHL).Methods:A retrospective case series study was conducted. The clinical data of 99 pediatric patients diagnosed with AHL who admitted to the Affiliated Huai'an No.1 People's Hospital of Nanjing Medical University between May 2015 and November 2020 were retrospectively analyzed. The enrolled children were grouped based on the following factors including gender, age, initial white blood cell count (WBC), initial lactate dehydrogenase (LDH), whether tumor lysis syndrome (TLS) occurred, immunophenotype, fusion gene, whether complete remission (CR) was achieved on the 19th day (D19) after transplantation, and whether CR was achieved on the 46th day (D46) after transplantation. All the patients were treated with the chemotherapy regimen of Shanghai Children's Medical Center - Acute Lymphoblastic Leukemia - 2015 (SCMC-ALL-2015). Flow cytometry was used to monitor the minimal residual disease (MRD); fluorescence in situ hybridization (FISH) was used to screen out the mutant genes. The median follow-up time was 47 months. The Kaplan-Meier method was used for survival analysis, and the log-rank test was used for intergroup comparisons. Multivariate Cox proportional hazard regression model was used to screen out the the prognostic factors.Results:Among 99 AHL patients, there were 65 males and 35 females; the median age was 7.71 (3.32, 11.20) years. At the initial diagnosis, 48 cases had WBC≤100×10 9/L, and 51 cases had WBC>100×10 9/L; 36 cases had LDH ≤ 2 000 U/L, and 63 cases had LDH > 2 000 U/L; 3 cases had TLS, 5 cases had MLL::AF4 positive, 7 cases had BCR::ABL positive, 7 cases had E2APBX1 positive, and 10 cases had TEL::AML1 positive; 28 cases were acute T-cell lymphoblastic leukemia (T-ALL), and 71 cases were acute B-cell lymphoblastic leukemia (B-ALL). At D19, 74 cases achieved bone marrow CR; at D46, 82 cases achieved bone marrow CR; 3-year and 5-year OS rates were 74.5% and 71.3%, respectively. During the follow-up, 14 cases relapsed and 15 died, including 12 dying of relapse, 2 dying of infection and 1 case dying of pulmonary graft-versus-host disease (GVHD). There were statistically significant differences in the 3-year OS rate in patients with different age, initial WBC, initial LDH, immunophenotyping, whether bone marrow CR at D19 was achieved, whether MRD at D19 occurred, whether bone marrow CR at D46 was achieved, whether MRD at D46 occurred, the presence of TLS, MLL::AF4 positive and TEL::AML1 positive (all P < 0.05). Furthermore, multivariate Cox regression analysis showed that LDH(>2 000 U/L), MLL::AF4 positive, T immunophenotyping, relapse, not achieving bone marrow CR at D19, not achieving bone marrow CR at D46, and MRD positive at D46 were independent risk factors influencing 3-year OS rate (all P < 0.05). Conclusions:Pediatric patients with AHL have high tumor burden at early stage, and TLS may cause death. Patients treated with the SCMC-ALL-2015 protocol can achieve favorable therapeutic effects and prognosis. LDH, MLL::AF4, immunophenotyping and relapse are prognostic factors.

Fifty children with refractory idiopathic thrombocytopenic purpura (RITP) were treated with rituximab (n =26) or vincristine (n =24).The response rate,adverse reaction and recurrence rate in two groups were compared.The CD19 +/CD20 + B cells in peripheral blood were detected by flow cytometry in 26 patients before and after RITP treatment.The response rates of rituximab group was significantly higher than that of vincristine group ( 69.2％ vs. 37.5％,x2 =9.74,P ＜ 0.01 ). There was no significant difference in the rate of adverse reaction between two groups ( 11.5％ vs.8.3％,x2 =0.62,P ＞ 0.05 ).The recurrence rate of rituximab group ( 22.2％ ) was significantly lower than that of vincristine group (55.6％,x2 =7.24,P ＜ 0.05 ).In rituximab group the platelet count after treatment was significantly higher than that before treatment ( t =12.48,P ＜0.01 ),and the ratio of CD19 +/CD20 + B cells decreased significantly after treatment compare to that before treatment ( t =6.71,P ＜0.05 ).Rituximab is effective in treatment of refractory idiopathic thrombocytopenic purpura in children,which may be associated with decreased B cells in peripheral bloos.