Objective To explore the bone marrow stromal cells,anti-late antigen-4 (VLA-4) antibody (aVLA-4),cytarabine (Ara-C) on the proliferation and apoptosis of leukemia HL-60 cells.Methods The experiment was divided into five groups:HL-60 cells were cultured alone (control group),HL-60 cells and stromal cells group (stromal cells group),HL-60 cells + stromal cells + aVLA-4 (antibody group),HL-60 cells + stromal cells + Ara-C group (drug group),HL-60 cells + stromal cells + aVLA-4 + Ara-C group (antibody +drug group).Cell proliferation or inhibition rate was detected by CCK-8 method,the HL-60 cells apoptosis was detected by flow cytometry.The expression of anti-apoptotic gene bcl-2 in HL-60 cells was determined by Western blot.Results After 24 h and 48 h,treatment,the number of the stromal cells group HL-60 cells were higher than that of the control group with significant difference cultured [(7.2±0.3)×1O5/ml vs (5.3±0.4)×105/ml,(8.4±0.2)×105/ml vs (6.8±0.3)×105/m1,P ＜ 0.001],while the HL-60 cell proliferation inhibition rate [(24.3±2.1) ％,(37.0±2.6) ％,(65.6±3.8) ％] and apoptosis rate [(5.7±0.6) ％,(8.0±0.5) ％,(10.4±0.9) ％,(16.5±0.7) ％] of antibody group,drug group,antibody + drug group were higher than the control group with a difference of statistically significant (P ＜ 0.05),and the increase of antibody + drug group was most obvious.With the decreasing of the bcl-2 protein expression,which was most the decrease of antibody + drug group was most obvious.Conclusion Bone marrow stromal cells can stimulate the proliferation of leukemia cells,aVLA-4 interference the interaction between stromal cells and leukemia cells can enhance the chemosensitivity of leukemia cells to Ara-C.

Objective: To study the diagnostic strategy of β-thalassemia through retrospective analysis of 3 cases of β-thalassemia. Methods: Three patients were admitted to the Department of Pediatrics, Sun Yat-sen Memorial Hospital of Sun Yat-sen University from January 2014 to June 2015. The clinical manifestations, hemoglobin electrophoresis and gene detection of these patients and their parents were analyzed, diagnostic ideas and key points were discussed when beta thalassemia gene detection did not explain clinical manifestations or hemoglobin electrophoresis. Results: Case 1, boy, 5 years old, was diagnosed as compound heterozygotes of β41-42 and IVS-Ⅱ-654 with hereditary persistence of fetal hemoglobin(HPFH) according to the clinical manifestations of mild anemia, normal size of liver and spleen, 92.8% fetal hemoglobin (HbF) and gene analysis. Case 2, girl, 3 years old, was confirmed the diagnosis of thalassemia intermedia with β41-42 heterozygote compound and ααα^anti3.7 heterozygote in accordance with the manifestations of severe anemia, hepatosplenomegaly, 8.6% HbF, 4.1% hemoglobin A₂(HbA₂) and gene analysis. Case 3, girl, 3 years old, with severe anemia, hepatosplenomegaly, 51.2% HbF and 3.7% HbA₂, was diagnosed as thalassemia major with compound heterozygotes of PolyA (T→C) and β17 by DNA sequencing. Conclusion The diagnosis of β-thalassemia should be confirmed by clinical manifestations of hemolytic anemia, hemoglobin electrophoresis, gene diagnosis and family survey.

Objective:To investigate the clinical characteristics and possible causes of transient spontaneous remission of childhood acute leukemia.Methods:The data of 3 children with acute leukemia who had transient spontaneous remission before standardized chemotherapy in Sun Yat-sen Memorial Hospital of Sun Yat-sen University in July 2018, May 2019 and October 2020 were collected. Moreover, the related influencing factors of spontaneous remission in leukemia were discussed by review of the literature.Results:All 3 children had fever at the onset of the disease, and they achieved transient spontaneous remission after anti-infection therapy. Case 1 obtained partial remission after the initial diagnosis of acute B lymphocytic leukemia (B-ALL), leukemia gene test showed E2A-PBX1 fusion, and relapsed after 12 days. Case 2 obtained spontaneous remission after the initial diagnosis of B-ALL, leukemia gene test showed p16 gene deletion and NRAS and EP300 genes mutation, and relapsed after 20 days. Case 3 obtained spontaneous remission after the initial diagnosis of acute monocytic leukemia, leukemia gene test showed MLL-ENL fusion and NRAS gene mutation, and relapsed after 30 days. A review of the literature showed that the main influencing factors of spontaneous remission in leukemia were Down syndrome, infection and blood transfusion. Other influencing factors included leukemia-related genes, termination of pregnancy and application of drugs.Conclusions:Transient spontaneous remission of childhood acute leukemia is rare in clinical practice, and the possible mechanism is related to infection-induced immune abnormalities. It is recommended that leukemia patients with spontaneous remission should be closely monitored for minimal residual disease.