[Objective]To investigate the effects of mesenchymal stem cells (MSC) feeder layer, culture sere and freeze-thaw lysates on expansion and differentiation of cord blood CD34~+ cells in vitro. [Methods] MSC were isolated from human bone marrow and cultured until the third passage. Sera were obtained from the cultured MSC, and freeze-thaw lysates were obtained by repeated freeze-thaw procedures. Cord blood CD34~+ cells were isolated by magnetic cell separation system, and were co-cultured with the MSC feeder layer, culture sera, freeze-thaw lysates and hematopeietic growth factors (HGFs), respectively. The nucleated cells, CD34~+ cells, CD34~+CD38~- cells, CD41~+ cells and CD3~+ cells in the above culture system were detected by flow cytometry on day 6 and day 12. [Results] ①MSC feeder layer had a strong effect on nucleated cells, CD34~+,CD34~+CD38~- cells expansion. The MSC sera and freeze-thaw lysates had similar effect on cell expansion, but the effect was weaker than that of feeder layer (P<0.05). ② Both MSC sera and feeder layer inhibited cord blood CD34~+ cells differentiation toward CD3~+ cells or CD19~+ cells, and no significant differences were found between these two groups (P>0.05). ③ Both MSC sera and feeder layer promoted cord blood CD34~+ cells differentiation toward CD41~+ cells, and the effect was stronger in the feeder layer than that of the sera (P<0.05). ④ Freeze-thaw lysates had no effect on cell expansion and differentiation, and were similar with that of HGFs (P>0.05). [Conclusions] The MSC sera have positive effects on expansion of cord blood CD34~+ and CD34~+CD38~- cells, moreover they have the ability of promoting cord blood CD34~+ cells differentiation toward CD41~+ cells.

AIM:To explore the supportive and expansive effects of aorta-gonad-mesonephros(AGM) region derived stromal cells on hematopoietic stem cells(HSC) in vitro.METHODS:The murine stromal cells were separated and cultured from AGM region of a 11 day postcoitum(dpc) mouse embryo and 6 week mouse.After identification by Wright's staining and flow cytometry,the stromal cells were co-cultured with the embryonic stem cell(ESC)-derived,cytokine-induced HSCs,and the maintenance and expansion of HSCs were evaluated by detecting CD34+,CD34+Sca-1+cells with flow cytometry.Blast colony-forming cell(BL-CFC) and high proliferative potential colony-forming cells(HPP-CFC) were determined by semi-solid medium clonal culture.RESULTS:AGM-derived and bone marrow(BM)-derived stromal cells were similar in morphology and phenotype,and had common character of stromal cells.Supported by AGM stromal cells or by BM stromal cells,more primitive progenitor cells HPP-CFC were expanded,but BL-CFC expansion was only detected in AGM-derived stromal cells.In the supporting of BM stromal cells CD34+ hematopoietic stem/progenitor cells were expanded 3-4 times,but no significant expansion in CD34+Sca-1+ cells was observed.While in the supporting of AGM stromal cells,both CD34+ hematopoietic stem/progenitor cells and CD34+Sca-1+ cells were expanded significantly from 4 to 5 times,respectively(P

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.

AIM: To study the isolation,expansion and purification of mesenchymal stem cells(MSCs) from human umbilical cord blood(UCB),and investigate some biological identities of MSCs.METHODS:(1) MSCs of UCB,adult bone marrow(BM) and fetus BM were isolated by centrifugation with Ficoll,and the different kinds of MSCs were observed everyday.(2) Surface markers of MSCs were identified by flow cytometry.(3) The level of HGFs(TPO,SCF,FLT-3L,IL-6) secreted by different sources of MSCs was checked by ELISA method.RESULTS:(1) No difference in morphology of the colonies between UCB MSCs and BM MSCs was observed.However,the mononuclear cells needed in culture of UCB MSCs was about 3 times more than that in culture of BM MSCs.The times of UCB MSCs colony formation and confluencing were longer than that of BM in primary culture.(2) After passaged,there was no significant difference in the proliferation rates of 3 kinds of MSCs.Only 4 of 15 UCB samples contained a homogeneous population of MSCs.(3) UCB MSCs shared the same markers with BM MSCs.Neither hematopoietic marker nor immunologic recognition antigens were expressed.(4) The level of hematopoietic growth factors(HGFs) secreted by 3 kinds of MSCs was similar.CONCLUSIONS:(1) MSCs were isolated from UCB,but the amount of MSCs in UCB was smaller than that in BM,and just seldom samples of UCB contained homogeneous MSCs.(2) MSCs from UCB and BM shared the same biological characteristics,such as proliferation ability,surface markers,immunophenotypes and HGFs secretion.

AIM: To investigate the efficacy of dendritic cells (DCs) that augments the cytotoxic activity of cytokine-induced killer (CIK) cells, natural killer (NK) cells from a same donor and the CD45RO expression on CIK cells. METHODS: The expanded killer cells were divided into two groups: group A was pre-cocultured with DCs for 6 days, group B was the control that without any stimulation. Cytotoxicity of CIK and NK cells was measured at different effect-target ratio against K562 and HL-60. CD45RO and CD45RA expression on CIK cells in different groups were detected by flow cytometry. RESULTS: Cytotoxicity of CB derived killer cells was positive correlation with effect-target ratio. The cytotoxicity of group A against HL-60 was higher than that of group B significantly. At 20∶1 effector-target ratio, the lytic activity of group A CIK, NK cells against K562 was higher than that of group B significantly, but no significant difference between them at 10∶1 effector-target ratio. The CD45RO expression on CIK cells in groups A was significantly higher than that in groups B. CONCLUSION: CIK and NK cells cocultured with DCs can augment the killer's cytotoxicity against tumor cells and promote the CD45RO expression on CIK cells.

BACKGROUND: Embryonic stem cells fESCs) develop from early blastular inner cell mass.Under proper condition,ESCs can maintain undifferentiated state in vitro,normal diploid nuclear type,and proliferative potential.In addition,ESCs possess multi-directional differentiation capacity and can differentiate into all sorts of cells of three germ layers. OBJECTIVE: To investigate the feasibility of directed differentiation of ESCs towards thyroid cells in vitro as well as related molecular expression. DESIGN,TIME AND SETTING: A cell-based observational experiment was performed at the Bank of Cord Blood,Second Hospital Affiliated to Sun Yat-sen University between January 2004 and December 2006.MATERIALS: Balb/c pregnant mice at pregnancy 12.5-14.5 days were used for preparation of embryonic fibroblast feeder layer.E14 mouse embryonic stem cell (ESC) strains were gifted by professor Xu from Harvard University.METHODS: Murine El4 ESCs were cultured in methylcellulose semisolid medium to form embryoid bodies (Ebs).These Ebs were transferred for further inductive culture with the stepwise addition of growth factors- thyrotropin (TSH),insulin and kalium iodidum (KI).The cultured thyroid cells of adult Kunming mice were taken as positive control.MAIN OUTCOME MEASURES: ①Cellular morphological change in the process of differentiation.② Detection of expression levels of TSHR,PAX8,TTF-2,and TIF-1 by immunofluorescence assay.③ Detection of expression levels of TSHR,PAX8,NIS,TPO,and Tg by reverse transcription-polymerase chain reaction (RT-PCR).RESULTS: The differentiated cells had clear boundary,exhibiting round,oval,shuttle-shaped,or polygon adhesive growth.On day 6 of inductive ifferentiation,the differentiated cells showed the expression of PAX8,NIS,TPO,Tg,and TSHR,the specific gene of thyroid ceils.On day 8 of inductive differentiation,the expression of TSHR,TIF-1,PAX8,and TIF-2 was detectable in the differentiated cells with morphous similar to thyroid cells.CONCLUSION: ESCs can differentiate towards thyroid cells under given inductive conditions.

Objective: To investigate the efficacy and safety of micafungin (MCF) for pulmonary invasive fungal disease (PIFD) in pediatric patients with acute leukemia or post hematopoietic stem cells transplantation. Method: Twenty-five neutropenic PIFD children with acute leukemia or post hematopoietic stem cells transplantation in Sun Yat-sen Memorial Hospital of Sun Yat-sen University were selected from January 2012 to June 2015, including 12 males and 13 females, age range 2-15 (average 6.2±2.0) years. There were 12 cases of acute leukemia (AL) after chemotherapy, 4 cases of acute leukemia (AL) after allogeneic hematopoietic stem cell transplantation (allo-HSCT) and 9 cases of β-thalassemia major after allo-HSCT. All children received MCM for the treatment of PIFD, the dosage of MCM was 3-4 mg/ (kg·d) , once a day. The children received 2 to 6 courses of treatment, individually with a course of 7 days. 1, 3-β-D glucan assay (G test), galactomannan antigen test (GM test), high-resolution CT and the biochemical indexes for organ functions were closely monitored. Result: Twenty-five cases were diagnosed as PIFD, including 2 patients diagnosed as proven, 6 as probable and 17 as possible. Of the 25 cases, 1 was confirmed aspergillus by biopsy pathology and 1 was candida albicans by blood culture. The G and GM test with positive results was 5 and 2 respectively. Chest CT scans of the 25 cases had obvious lesions: air crescent sign and cavitation in 4 cases, diffuse ground glass change in 9 cases, double lung scattered patchy, small nodules and cord like high density shadow in 7 cases, unilateral or bilateral chest wall wedge-shaped consolidation edge in 5 cases and pleural effusion in 5 patients. The effective rate of MCF in treatment of PIFD was 68% (17/25), including 13 cases cured, 4 cases improved, 4 cases were improved clinically and in 4 cases the treatment was ineffective. Eight cases were effective in MCF monotherapy group (12 cases) and nine were effective in MCF combined therapy group(13 cases), respectively. Side-effects including allergies, gastrointestinal side effects, electrolyte disturbances, impairment of liver and kidney function, and myelosuppression were not found in those children treated with MCF. Conclusion Micafungin is effective and safe in the treatment of pulmonary invasive fungal disease in pediatric patients with acute leukemia or post hematopoietic stem cell transplantation.

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 analyze the short-term clinical efficacy and safety of arsenic trioxide (ATO) combined with a modified N7 induction regimen in the treatment of children with high-risk neuroblastoma (NB).Methods:This study was a prospective, single-arm, multicenter phase Ⅱ clinical study. Sixty-seven high-risk NB children from eight units of Sun Yat-sen Memorial Hospital of Sun Yat-sen University, Wuhan Children′s Hospital of Tongji Medical College of Huazhong University of Science and Technology, First Affiliated Hospital of Guangxi Medical University, Hainan General Hospital, Affiliated Hospital of Guangdong Medical University, Kunming Children′s Hospital, Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology, and Guangdong Provincial Agricultural Reclamation Center Hospital were enrolled from January 2019 to August 2023 and were treated with ATO combined with a modified N7 induction regimen. The efficacy and adverse effects at the end of induction chemotherapy were assessed and analyzed, and the differences in the clinical characteristics were further compared between the treatment-responsive and treatment-unresponsive groups by using the Fisher′s exact test.Results:Among 67 high-risk NB children, there were 40 males (60%) and 27 females (40%), with the age of disease onset of 3.5 (2.6, 4.8) years. Primary NB sites were mostly in retroperitoneum (including adrenal gland) (56/67, 84%) and the common metastases sites at initial diagnosis were distant lymph node in 25 cases (37%),bone in 48 cases (72%),bone marrow in 56 cases (84%) and intracalvarium in 3 cases (4%). MYCN gene amplification were detected in 28 cases (42%). At the end of induction, 33 cases (49%) achieved complete remission, 29 cases (43%) achieved partial remission, 1 case (1%) with stable disease, and 4 cases (6%) were assessed as progressive disease (PD). The objective remission rate was 93% (62/67) and the disease control rate was 94% (63/67). The percentage of central system metastases at the initial diagnosis was higher in the treatment-unresponsive group than in the treatment-responsive group (2/5 vs. 2% (1/62), P=0.013), whereas the difference in MYCN gene amplification was not statistically significant between two groups (3/5 vs.40% (25/62), P=0.786). Grade Ⅲ or higher adverse reactions during the induction chemotherapy period were myelosuppression occurred in 60 cases (90%), gastrointestinal symptoms occurred in 33 cases (49%), infections occurred in 20 cases (30%), hepatotoxicity occurred in 4 cases (6%), and cardiovascular toxicity occurred in 1 case (2%). There were no chemotherapy-related deaths. Conclusion:ATO combined with N7-modified induction regimen had a superiority in efficacy and safety, which deserved further promotion in clinical practice.