AIM: To evaluate the biological characteristics and differentiating potentials of bone marrow-derived mesenchymal stem cells(MSCs) from sensitized mice by allogeneic splenocyte transfusion in vitro.METHODS: Adherent culture method was applied for culturing the bone marrow-derived MSCs from sensitized mice.The cell morphology was examined and the surface marker profiles were analyzed by flow cytometry.The differentiating potentials of the MSCs into osteogenic,adipogenic and myogenic lineages were explored.The bone marrow-derived MSCs from the normal mice were collected and served as controls.RESULTS: Both the bone marrow-derived MSCs from sensitized and normal mice were exhibited a homogeneous distinctive morphology and were positive for the surface markers CD29,CD105,CD44 and Sca-1,negative in CD 34 and CD11b.The abilities of both MSCs to differentiate into osteogenic,adipogenic and myogenic pathways in the same condition were also observed.CONCLUSION: There is no difference in the biological characteristics and induced differentiating potentials between the sensitized mouse bone marrow-derived MSCs by allogeneic splenocytes transfusion and the MSCs from normal mice.

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 observe the clinical efficacy and adverse reaction of the combination of fiudarabine,cytarabine and granulocytecolony-stimulating factor (G-CSF) (FLAG regime) therapy for refractory and relapsed acute leukemia in children. Methods From 2004 to date, a total of 9 patients with relapsed and refractory acute leukemia patients in our hospital accepted the treatment, in 9 cases 8 cases were AML,1cases were ALL; in 9 cases 5 cases were refractory acute leukemia, 4 cases were recurrent acute leukemia.Results Among the 9 cases,6 cases with 1 cycles of chemotherapy achieved complete remission (CR),CR rate was 66.7 ％ (6/9); partial remission (PR) rate was 22.2 ％ (2/9),total efficiency (CR+PR) was 88.9 ％.In 6 CR patients 2 underwent hematopoietic stem cell transplantation, are disease-free survival; this regimen' s main adverse reactions were infection,bone marrow depression and gastrointestinal reaction.Conclusion The remission rate of FLAG regimen in the treatment of children with refractory and relapsed acute leukemia is relatively high, adverse reactions were tolerable; the FLAG program is a choice for the treatment of children with refractory and relapsed acute leukemia,which provides the opportunity for subsequent hematopoietic stem cell transplantation.

BACKGROUND: Panel reaction antibody (PRA) plays an important role in rejection of recipients undergoing solid organ transplantation, which has a positive effect on nonfunction of implant. OBJECTIVE: To evaluate the effect of thalassemic serum-specific PRA on the proliferation and differentiation of umbilical cord blood hernatopoetic stem/progenitor cells (HSC/HPCs) in children patients with thalassemia. DESIGN, TIME AND SETTING: The in vitro cytology experiment was performed at the Experimental Research Center, Second Affiliated Hospital, Zhongshan University from January 2006 to August 2007. MATERIALS: Five samples of umbilical cord blood from healthy full-term birth puerperants (each 80 100 mL) were used in this study. PRA serum samples of children patients with thalassemia after repetitive blood transfusion, five samples of AB blood grouping serum, and six samples of positive anticoagulation vein blood (10 mL) were used in the study. METHODS: Mononuclear cells were harvested from umbilical cord blood by Ficoll-Hypaque gradient centrifugation. 1 × 105 rnononuclear cells from umbilical cord blood were incubated with different levels of experimental or AB control serum (0, 50, 100 μ L) from healthy children. The mixture mentioned above was incubated with rabbit complement for semisolid colony culture.MAIN OUTCOME MEASURES: Colony-forming units (CFU) were counted and observed after 7 days and 14 days of culture under an inverted microscope.RESULTS: After incubation with HSC/HPCs PRA serum, total number of CFUs and varied CFUs decreased to different extents, of which the total number of CFUs and CFU- granulocyte-rnacrophages (CFU-GM) had significant differences (P < 0.01). Moreover, there were negative correlations between different levels of serum PRA and the followings: number of total colonies, CFU- GM, CFU- granulocyte-erythrocyte-monocyte-megakaryocytes, CFU-erythroids, burst forming unit-megakaryocytes, and CFU-megakaryocytes (P < 0.05).CONCLUSION: The thalassemic serum PRA has an apparent inhibitory effect on the proliferation and differentiation of cord blood HSC/HPCs in vitro, an effect that may be pronounced with increasing serum PRA.

BACKGROUND: Hemorrhagic cystitis (HC) is one of common complications in patients undergoing hematopoietic stem cell transplantation (HSCT). It is of great value for improvement in the HSCT outcome to describe the clinical characteristics of HC and risk factors. OBJECTIVE: To investigate the incidence of HC in children after HSCT, and to analyze its clinical characteristics and risk factors.DESIGN: Case analysis SETTING: Center of Hematopoietic Stem Cell Transplantation, Department of Pediatrics, Second Affiliated Hospital of Sun Yat-sen University.PARTICIPANTS: Experiments were performed at the Center of Hematopoietic Stem Cell Transplantation, Department of Pediatrics of Second Affiliated Hospital of Sun Yat-sen University from October 1998 to June 2004. Eighty-eight patients receiving umbilical cord blood transplantation (UCBT) and peripheral blood stem cell transplantation (PBSCT) were enrolled; 49 were males and 39 were females. The age ranged from 2 to 18 years with an average of 8.0 years. Guardians of child patients signed informed consents. The experimental procedures were approved by Medical Ethics Committee.METHODS: ①Conditioning regimens included combination of cyclophosphamide (CY, 120-200 mg/kg) with busulphan (BU, 14-20 mg/kg)-based chemotherapy and combination of CY with total body irradiation (TBI, 2-8 Gy) or total lymphoid irradiation (TLI, 2-8 Gy)-based radiotherapy. ②HC was defined according to the criteria proposed by references 7 and 8. The incidence, clinical characteristics, laboratory examination, treatment and outcome for HC were described. The association of various clinical factors including age, gender, human leucocyte antigen (HLA) typing, diseases for transplant, the type of stem cell, the type of transplantation, the occurrence of acute graft-versus-host disease (aGVHD) and cytomegalovirus (CMV) infection with the development of HC were examined.MAIN OUTCOME MEASURES: ①Incidence of HC, ②HC patient characteristics and laboratory examination, ③HC treatment and outcome, and ④risk factors analysis. RESULTS: All 88 patients were included in the final analysis. ①The incidence of HC: 16 patients (18.2%, 16/88) developed HC post-transplant with the severity graded as mild in 11 cases (68.7%) and severe in 5 cases (31.3%). ②HC patient characteristics and laboratory examination: All had hematuria and 8 cases (50.0%) had typical pollakisuria, urinary urgency, odynuria and gross hematuria; 10 cases (62.5%) had gross hematuria and 11 had proteinuria (+ to +++); Leucocytes were detected in 7 cases. ③Treatment and outcome: All patients recovered at a median of 13.5 days (range 2-53 days). ④Risk factors analysis: The incidence of HC was significantly higher in the group of ≥ 6 years old, presence of aGVHD and development of cytomegalo-virus (CMV) infection (P < 0.05-0.01). CONCLUSION: ①HC has its own clinical characteristics following HSCT in children but with good prognosis. ②The risk factors for HC are ≥ 6 years old, presence of aGVHD and CMV infection.

Platelet is an important component of human blood, which plays a key role in the physiological and pathological processes. Recently, novel drug delivery system based on platelet and platelet membrane bionics attracted much attention. Compared to the traditional drug carriers, platelet and platelet membrane-based biomimetic drug delivery system has great performances in biocompatibility, longer circulation and stronger ability of targeting. This review presented the features, classifications, drug-loading and applications of platelet and platelet membrane-based biomimetic drug delivery systems, promoting their development and application in the future.

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.

Objective:To explore the clinical characteristics and management of childhood acute lymphoblastic leukemia (ALL) complicated with cerebral venous thrombosis (CVT).Methods:The clinical data of 14 ALL children complicated with CVT who were admitted to Department of Pediatrics of Sun Yat-sen Memorial Hospital and underwent chemotherapy from January 2011 to October 2019 were collected retrospectively. The clinical manifestations, coagulation function, imaging findings, treatment plan and prognosis of patients were analyzed.Results:CVT was diagnosed in 14 (2.8%, 14/505) cases, with a median age of 10 (3-14) years at onset, 11 cases occurred in the stage of induction remission, and the acute onsets were mainly characterized by convulsions (9 cases), consciousness disorders (6 cases) and headache (4 cases). Coagulation function test showed that, before the CVT, antithrombin Ⅲ activity was lower than 60% in 8 cases, D-dimer elevated on the day of onset in 8 cases. Arteriovenous angiography showed filling defects in single (9 cases) or multiple (5 cases) venous sinuses. The most common site of venous sinus enlargement was superior sagittal sinus (10 cases). Secondary cerebral hemorrhage was found in 5 cases. Anticoagulation therapy included combination of low-molecular-weight heparin (LMWH) and warfarin in 9 cases, sequential application of LMWH and warfarin in 2 cases, and LMWH alone in 3 cases. Patients accepted further asparaginase and no CVT recurrence or progression was found.Conclusions:The secondary coagulation dysfunction during induction remission chemotherapy is the major risk factor for CVT in ALL, which needs active monitoring and early prevention. Arteriovenous angiography can diagnose accurately, and the prognosis of anticoagulant therapy with LMWH and warfarin is optimistic.

Objective:To evaluate the efficacy and safety of eltrombopag for children with thrombocytopenia after hematopoietic stem cell transplantation (HSCT).Methods:Clinical data of 24 patients with thrombocytopenia after HSCT,who were treated with eltrombopag in the Department of Pediatrics, Sun Yat-sen Memorial Hospital, Sun Yat-sen University from August 1, 2018 to April 1, 2019 were analyzed retrospectively. The response rate and adverse reactions of eltrombopag were evaluated. Patients were divided into groups by source of hematopoietic stem cells (umbilical cord blood group and peripheral stem cell group) and type of disease (malignant and non-malignant disease group) and the clinical outcomes between groups were compared. Rank Sum test was used for comparisons between groups.Results:Among 24 cases, 15 were males and 9 females, the age of starting eltrombopag was 7.7 (2.6-13.7) years, the time of eltrombopag treatment after HSCT was 27.5 (8.0-125.0) days, the time from treatment to complete response (CR) was 23.5 (6.0-83.0) days, with the treatment course 36.5 (8.0-90.0) days. The total dose of eltrombopag was 1 400(200-5 900) mg. Complete response rate was 92% (22/24),without eltrombopag related adverse reactions. Comparing with peripheral stem cell group ( n=8), the course and total dose of eltrombopag in umbilical cord blood group ( n=16) were significantly reduced(24.5 (8.0-81.0) vs. 65.5 (35.0-90.0) d, Z=-3.004, P=0.002; 900.0 (200.0-3 850.0) vs. 2 862.5 (1 175.0-5 900.0) mg, Z=-2.604, P=0.007), but no significant differences were found in the time from treatment to complete response, platelet count after 2 weeks of eltrombopag withdrawal or platelet count at the end point of follow-up (all P>0.05). Comparing malignant patients ( n=12) and non-malignant patients ( n=12), no significant differences were found in the time from treatment to complete response, course, total dose, platelet count after 2 weeks of eltrombopag withdrawal, and platelet count at the end point of follow-up in non-malignant patients (all P>0.05). Conclusion:Eltrombopag is safe and maybe effective for thrombocytopenia after HSCT, especially for umbilical cord blood transplantation.