Objective:To explore the characteristics, diagnosis, and treatment of precursor B-cell acute lymphocytic leukemia with C- MYC rearrangement (preBLL) in children. Methods:The clinical data in 2 cases of childhood preBLL in Department of Hematology, Children′s Hospital Affiliated to Capital Institute of Pediatrics in June and August 2019 were summarized and analyzed.Results:Both cases were acute lymphoblastic leukemia with precursor B-cell immunophenotype.Hepatosplenomegaly and peripheral white blood cells were significantly increased, and the morphology of bone marrow was L3. C- MYC rearrangement was discovered by cytogenetic tests.Both children have received the treatment of the mature B-cell tumor protocol (FAB/LMB96), and early remission was developed in 1 case with TP53 gene mutation but relapsed thereafter and died finally.Another case had reached sustained complete remission after treatment. Conclusions:Children with preBLL is rare, and routine C- MYC rearrangement should be performed in children with Precursor B-cell lymphoblastic leukemia whose morphology of bone marrow was L3.Its treatment needs to be further studied, and multi-center clinical trials need to be actively conducted to analyze and summarize large numbers of cases to identify effective protocol and improve the prognosis.

OBJECTIVETo observe the efficacy and adverse reaction of the improvement program of cladribine combined with cytarabine (2-CdA+Ara-C) in treatment of children with refractory high-risk Langerhans cell histiocytosis (LCH).

METHODS13 patients with refractory high-risk LCH or recurrent LCH were treated by combined 2-CdA+Ara-C chemotherapy. The treatment efficacy and the disease state in the process were evaluated according to the Histiocyte Society Evaluation and Treatment Guidelines (2009). The drug toxicity was evaluated according to the Common Terminology Criteria Adverse Events Version 4.0 (CTCAE v4.0, 2009).

RESULTSOf 13 patients, 10 cases achieved non active disease (NAD); 2 patients with liver cirrhosis before the improvement program with CIP-LCH-2012 gave up the treatment after 1 course of therapy; 1 patient died of infectious shock after chemotherapy with severe pulmonary infection and intestinal infection. All 13 patients had grade 3 of blood and lymphatic system toxicity; 10 patients had grade 1 of hepatobiliary and gastrointestinal side effects; 3 patients with liver cirrhosis before the improvement program had grade 2 or grade 3 of hepatobiliary system and gastrointestinal system side effects, including 1 patient of death.

CONCLUSIONThe improvement program of CIP-LCH-2012 had significant efficacy for children with refractory high-risk and relapsed LCH. The cladribine-associated toxicity was of significant myelosuppression, which may be tolerated in the most children patients. The program could be considered as a recommended salvage therapy for multi-system LCH (MS-LCH) after failure of first-line therapy, and as a first-line therapy for MS-LCH with risk organ injury. The program should be used with caution or dose-adjustment consideration for pre-treatment of severe organ damage exist, especially cirrhosis.

Child ; Cladribine ; therapeutic use ; Histiocytosis, Langerhans-Cell ; drug therapy ; Humans ; Immunosuppressive Agents ; therapeutic use ; Risk Factors ; Salvage Therapy