Impact of posttransplant cyclophosphamide on the outcome of patients undergoing unrelated single-unit umbilical cord blood transplantation for pediatric acute leukemia.

BACKGROUND: Umbilical cord blood transplantation (UCBT) from unrelated donors is one of the successful treatments for acute leukemia in childhood. The most frequent side effect of UCBT is peri-engraftment syndrome (PES), which is directly associated with the greater prevalence of acute and chronic graft-versus-host-disease (aGvHD and cGvHD). In haploidentical stem cell transplantation, posttransplant cyclophosphamide (PTCY) has been demonstrated to be an effective method against GvHD. However, the effects of PTCY as a GvHD prophylactic in UCBT had not been investigated. This study aimed to evaluate the effects of PTCY on the outcomes of UCBT for pediatric acute leukemia. METHODS: This retrospective study included 52 children with acute leukemia who underwent unrelated single-unit UCBT after myeloablative conditioning regimens. The results from the PTCY and non-PTCY groups were compared. RESULTS: The incidence of transplantation-related mortality in non-PTCY and PTCY were 5% and 10% (p = 0.525), respectively. The incidence of relapse in non-PTCY and PTCY were 5% and 23% (p = 0.095), respectively. Second complete remission status (CR2) was an independent risk factor for relapse-free survival (hazard ratio = 9.782, p = 0.001). The odds ratio for sepsis or bacteremia incidence was significantly greater in the PTCY group (9.524, p = 0.017). PTCY group had increased rates of cytomegalovirus activity and fungal infection. The incidence of PES, aGvHD, cGvHD, and hemorrhagic cystitis in the PTCY group was lower than that in the non-PTCY group, although it was not significantly different. Additionally, higher doses of PTCY (29 mg/kg and 40 mg/kg) were associated with lower incidences of aGvHD and severe GvHD (65% and 29%, respectively) than lower doses (93% and 57%, respectively). Engraftment time and graft failure incidence were similar across groups. CONCLUSION: The results support the safety and efficiency of PTCY as part of PES controlling and GvHD prophylaxis in single-unit UCBT for children with acute leukemia. A PTCY dosage of 29 mg/kg to 40 mg/kg appears to be more effective in GvHD prophylaxis for UCBT patients.

Modified conditioning regimen improves outcomes of unrelated donor peripheral blood stem cell transplantation for ß-thalassaemia major patients.

BACKGROUND: The objective of this study was to evaluate the feasibility of a modified conditioning regimen for the treatment of patients with ß-thalassaemia major (TM), using unrelated donor peripheral blood stem cell transplantation (UD-PBSCT). METHODS: A modified conditioning regimen based on intravenous busulfan, cyclophosphamide, fludarabine, and antithymocyte globulin was performed in 50 consecutive childhood patients with ß-TM and a median age of 4.6 years (range, 2-12 years). According to Pesaro's classification, three classes of risk are identified using the criteria of degree of hepatomegaly, portal fibrosis, and quality of the chelation treatment. Patients with three adverse criteria constituted class III, none of the adverse criteria constituted class I, and one or two of the adverse criteria formed class II. Ten patients were class I, 36 class II, and four class III. All patients were transplanted with UDs containing 37 of 10/10 human leukocyte antigen (HLA)-matched pairs, 11 of 9/10 matched pairs, and two of 8/10 matched pairs. The median follow-up was 36 months (range, 9-96 months). RESULTS: All patients successfully achieved engraftment, two of whom developed persistent thrombocytopaenia. The incidence of acute graft-versus-host disease (aGVHD) grade III-IV and chronic graft-versus-host disease (cGVHD) were 12% and 8%, respectively. However, 8.3% of HLA-matched and 15.4% of HLA-mismatched patients developed aGVHD. The incidence of severe bacterial infections and fungal pneumonia was 12% and 20%, respectively. The 3-year overall survival, disease-free survival, graft rejection, and transplant-related mortality were 94%, 92%, 2%, and 6%, respectively. CONCLUSION: This modified conditioning protocol effectively improved outcomes of UD-PBSCT for patients with ß-TM.

LW-213 induces G2/M cell cycle arrest through AKT/GSK3ß/ß-catenin signaling pathway in human breast cancer cells.

LW-213 is a derivative of Wogonin and the anticancer activities of Wogonin have been reported. To study whether LW-213 inhibits cancer cells and explore a possible mechanism, we investigate the compound in several cancer cell lines. We found LW-213 arrests G2/M cycle in breast cancer cells by suppression of Akt/Gsk3ß/ß-catenin signaling pathway. In compound treated cells, cell cycle-related proteins cyclin A, cyclin B1, p-CDK1, p-Cdc25C, and p-Chk2 (Thr68) were upregulated, and ß-catenin nuclear translocation was inhibited. Electrophoretic mobility shift assay revealed LW-213 inhibits binding of ß-catenin/LEF complex to DNA. GSK3ß inhibitor LiCl and siRNA against GSK3ß partially reversed G2/M arrest in breast cancer MCF-7 cells. These results suggest LW-213 triggered G2/M cell cycle arrest through suppression of ß-catenin signaling. In BALB/c mice, growth of xenotransplanted MCF-7 tumor was also inhibited after treatment of LW-213. Regulation of cyclin A, cyclin B1, and ß-catenin by LW-213 in vivo was the same as in vitro study. In conclusion, we found LW-213 exerts its anticancer effect on cell proliferation and cell cycle through repression of Akt/Gsk3ß/ß-catenin signaling pathway. LW-213 could be a potential candidate for anticancer drug development.

[Therapeutic efficacy evaluation of rabbit anti-thymocyte globulin combined with cyclosporine A in children with aplastic anemia].

This study was aimed to investigate the therapeutic efficacy of rabbit anti-thymocyte globulin (r-ATG) combined with cyclosporine A (CsA) and to analyse the efficacy-related factors in children with aplastic anemia (AA). Twenty five AA children treated with r-ATG [3.5 mg/(kg·d)×5 days] combined with CsA were analyzed retrospectively. The lymphocyte subgroups, CD4(+)/CD8 ratio and expression of CD55, CD59 on surface of neutrophils and erythrocytes in peripheral blood were detected by direct immunofluorescence method and flow cytometry; the responsive time, effective rate, adverse effects and infections after immunosuppressive therapy (IST) were analyzed; the distribution of T-lymphocyte subgroups in IST-effective and IST-uneffective groups was compared, and therapeutic efficacy-related factors were evaluated. The results showed that the response to treatments was found in 21 out of 25 cases, the total responsive rate was 84.0%; the response time was 3 - 6 months, average of 4 months; the effective rates in month 3, 6, 9, 12 after treatment were 56.0%, 72.0%, 80.0% and 84.0% respectively. The AA children with age ≥ 5 years old, course of disease < 6 months and absolute neutrophil value ≥ 1.5 ×10(9)/L on 30 days after IST had good curative effect; the effective rate in AA children with age ≥ 5 years old, course of disease < 6 months, high or reverse ratio of CD4(+)/CD8(+) and absolute neutrophil value ≥ 1.5×10(9)/L after IST was higher than that in AA children with age < 5 years old, course of disease ≥ 6 months, normal ratio of CD4(+)/CD8(+) and absolute neutrophil value after IST < 1.5×10(9)/L (94.4% vs 57.1%, 90.4% vs 50.0%, 94.1% vs 62.5%, 94.1% vs 62.5%) (P < 0.05). The high effective rate was observed in AA children with decrease of CD55 and CD59 expression, but there was no significant difference (P > 0.05) as compared with normal expression of CD55, CD59. It is concluded that the treatment using r-ATG (3.5 mg/kg·d × 5 d) combined with CsA is a safe and effective for children with AA. Age, course of disease and absolute neutrophil value on 30 days after IST are the main factors affecting curative affect.

[Analysis of one case of adolescent blastic plasmacytoid dendritic cell neoplasm].

This study was purposed to summarize the clinical characteristics and laboratorial data of blastic plasmacytoid dendritic cell neoplasm (BPDCN) in pediatric patients in order to enhance understanding this disease in diagnosis and therapy. A rare case of BPDCN in children was enrolled in this study. The blood routine test, examination of bone marrow cell morphology, histopathology and immunophenotype of the skin lesions were performed and analysed, the single cell suspensions of the biopsied skin mass were detected by flow cytometry. The results showed that tumor cells expressed CD4, CD56, CD43 and CD123, while not expressed CD19, CD20, CD3, CD8, CD13, CD11b and myeloperoxidase (MPO). According to the clinical and laboratorial features and the results from histopathological and immunophenotype examinations, BPDCN was confirmed. It is concluded that BPDCN in children is an extremely rare hematopoietic malignancy with presenting a rapidly and fatally aggressive clinical course. The diagnosis of this disease is mainly based on the clinical presentations, pathologic and immunohistochemical features. BPDCN is a highly aggressive disease, its prognosis is very poor, its pathogenesis remans still unclear. A standard treatment protocol for BPDCN has not yet been established.

Rabbit-antithymocyte globulin combined with cyclosporin A as a first-line therapy: improved, effective, and safe for children with acquired severe aplastic anemia.

PURPOSE: Acquired aplastic anemia is an organ-specific auto-immune disease characterized by pancytopenia and hypoplastic bone marrow. Immunosuppression with anti-thymocyte globulin (ATG) and cyclosporine A (CsA) is an effective and safe therapy for patients without undergoing hematopoietic stem cell transplantation. The aim of the current study was to investigate the effect of rabbit-ATG (r-ATG) combined with CsA as an intensive immunosuppressive therapy (IST) for acquired severe aplastic anemia (SAA) in children. METHODS: From January 2003 to November 2008, 46 children (30 boys and 16 girls), with a median age of 7 years (between 2 and 15 years) were diagnosed with acquired SAA. They received an IST of r-ATG combined with CsA. The average time was 3.4 months (ranging from 1 to 13 months). The effective rates 3, 6, 9, and 12 months after treatment were 30.4, 65.2, 78.8, and 84.8%, respectively. After 2 years of follow-up, the response rate was 84.8% (39/46). No response was found in five cases and relapse was found in two. RESULTS: Among the five cases without response, two received unrelated hematopoietic stem cell transplantation and are already disease-free and two died from infection caused by long-term dependence on infusion. No myelodysplastic syndrome or acute myeloid leukemia was found among the patients. CONCLUSIONS: We propose that r-ATG combined with CsA as an intensive IST is effective and safe in treating acquired SAA in children.

[Sequentially inducting murine embryonic stem cells into hematopoietic stem cells in vitro by hematopoietic development procedure for reconstitution of hematopoiesis in vivo].

This study was purposed to directly induce murine embryonic stem cells (ESC) into hematopoietic stem cells (HSC) by simulating the spatial and temporal hematopoietic microenvironment changes in embryonic development, and to investigate the function of in vivo hematopoietic reconstitution of these HSC. E14 ESC were induced into embryoid body (EB) firstly. Then the cells from EB were further co-cultured with human aorta-gonad-mesonephros (AGM) region, fetal liver (FL) and bone marrow (BM) stromal cells in Transwell non-contact system in sequential orders. After 6 days of each co-cultured stage, the induced cells derived from EB were collected to analyze the Sca-1(+)c-Kit(+) cells by flow cytometry, check teratoma formation and transplant to BALB/C female mice exposed to lethal dose (60)Co γ-ray. The recipient mice were divided randomly into 5 groups: AGM, AGM + FL, AGM + FL + BM, irradiation control and normal control groups. The survival rates, hematopoietic reconstitution and engraftment of donor cells in the different groups were monitored. The results showed that Sca-1(+)c-Kit(+) cell level in EB cells co-cultured with human AGM region and FL stromal cells reached to peak value (21.96 ± 2.54)%. Teratomas could be found in NOD-SCID mice after subcutaneous injection of EB cells co-cultured with human AGM region stromal cells, while there was no teratoma in the mice after subcutaneous injection of EB cells induced by human AGM region and FL stromal cells. The recipients in AGM group and irradiation control group all died. The survival rate was 77.8% in AGM+FL group, and 66.7% in AGM+FL+BM group. The peripheral blood cell count was near normal at day 21 after transplantation, and Sry gene copies from donor could be detected in recipient mice of these two groups. It is concluded that sequentially inductive system with feeder cells from human AGM region, fetal liver and bone marrow simulating embryonic defined hematopoiesis procedures can enhance the directed differentiation of ESC into HSC which can safely reconstitute hematopoiesis in vivo.

[Effects of human aorta-gonad-mesonephros region stromal cells on inducing differentiation of murine embryonic stem cells into hematopoietic stem/progenitor cells in vitro].

This study was aimed to investigate the effect of human aorta-gonad-mesonephros (AGM) region stromal cells on differentiation of murine embryonic stem cells (ESC) into hematopoietic stem cells (HSC) in vitro and to clarify their effect mechanism. E14 murine ESC were induced into embryo body (EB) firstly. Then the EB cells were further co-cultured with the stromal cells from human AGM region, fetal liver (FL) or bone marrow (BM) in Transwell non-contact system. According to the different culture methods, the EB cells were divided into 6 groups including EB control group, AGM group, FL group, BM group, AGM + FL group and AGM + BM group. The induced cells derived from EB were collected for Sca-1(+)/c-Kit(+) cells analysis by flow cytometry and colony forming unit (CFU) assay. The results showed that Sca-1(+)/c-Kit(+) cell proportion of EB cells significantly increased after being induced by different stromal cells (p < 0.01). The AGM + FL group had most Sca-1(+)/c-Kit(+) cells for the positive cell proportion reached (21.96 ± 2.54) % (p < 0.01). The Sca-1(+)/c-Kit(+) cell proportion of AGM + BM group was much high than that of BM group too (p < 0.01). The EB control group showed CFU amount less than any other groups, while the CFU amount of AGM + FL, AGM + BM groups were higher, especially in the AGM + FL group (p < 0.01). It is concluded that the human AGM region stromal cells may help to maintain certain number of primitive HSC with high proliferation potential. Human AGM region, FL or BM stromal cells, applied in sequential orders, can significantly expand in vitro the primitive hematopoietic stem/progenitor cells derived from ESC.

Allogeneic hematopoietic stem cell transplantation for childhood aplastic anemia: prospective trial in China.

We aim to investigate the efficacy and safety of the treatment with fully matched allogeneic hematopoietic stem cell transplants for children with severe aplastic anemia (SAA) in the first prospective trial in China. Six SAA children received allogeneic hematopoietic stem cell transplantation combined with chemotherapy. Five patients had successful engraftment while the sixth child regained normal peripheral blood counts consistent with spontaneous autologous hematopoiesis. Mean duration of follow-up was 2.75 years, and survival was 83%(5/6). The results indicated that allogeneic hematopoietic stem cell transplantation is a good option for the treatment of children with severe aplastic anemia.

Bone marrow mesenchymal stem cells reduce the antitumor activity of cytokine-induced killer/natural killer cells in K562 NOD/SCID mice.

Adoptive cellular immunotherapy is an important treatment to eliminate residual tumor cells after hematopoietic stem-cell transplantation. Bone marrow mesenchymal stem cells (MSC) have previously been shown to exert immunoregulation functions, including inhibition of proliferation and killing activities of T cells and natural killer (NK) cells in vitro and reduction of the graft-versus-host disease. MSC can survive in vivo for a long period of time, the influence of MSC on the antitumor activity of subsequently infused immune killer cells is not clear. The aim of this study was to investigate the influences of MSC infused via different paths and at different times on the antitumor activities of cytokine-induced killer (CIK)/NK cells derived from umbilical cord blood in K562 NOD/SCID mice. The potential interaction mechanisms of MSC and CIK/NK cells infused through different paths using different intervals in vivo were subsequently explored. The results show that the antitumor activities of CIK/NK cells was inhibited by MSC when injected via the same path (tail vein), and the suppressive effect of MSC on CIK/NK cells were less pronounced when they were injected separately through different paths. There were no effects of MSC on the antitumor activities of CIK/NK cells if the MSC and CIK/NK cells were injected with a 48-h interval. Moreover, the suppressive effect continuous, even if MSC were infused 48 h earlier than CIK/NK cells. It suggests that pre-injected MSC can reduce the antitumor activities of CIK/NK cells in vivo. The probable mechanisms are that MSC and CIK/NK cells might have a greater opportunity to meet and interact if they are injected simultaneously via the same path. The suppression of MSC on CIK/NK cells in vivo mainly takes place in the reticuloendothelial system, including the lung and the liver.

[Influence of FcγRIIIa polymorphism on rituximab-dependent NK cell-mediated cytotoxicity to Raji cells].

Fcgamma receptor IIIa (FcγRIIIa) polymorphisms is considered to influence clinical response to therapeutic monoclonal antibody (McAb) in cancer, most people believe it can affect McAb binding, and McAb-dependent NK cell-mediated cytotoxicity. This study was purposed to determine the difference of antibody-dependent cell-mediated cytotoxicity (ADCC) effects mediated by different FcγRIIIa NK cells. The FcγRIIIa genotypes were detected by nest-PCR, the target cells (Raji cells) were stained with 5- (and 6-) carboxyfluorescein diacetate succinimidyl ester (CFSE), cultured with effector cells with different FcγRIIIa genotypes, and finally stained with propidium iodide (PI); the CD20 expression of Raji cells were tested by flow cytometry and cytotoxic index was calculated as well. The results indicated that the ADCC cytotoxic indexes of NK cells with FcγRIIIa-158V/V and FcγRIIIa-158V/F were 69.05±2.38% and 39.63±3.86% respectively, as compared with NK cells with FcγRIIIa158 V/V, ADCC effect of NK cells with FcγRIIIa-158 on Raji cells was obviously weakened with significant difference (p<0.05). It is concluded that FcγRIIIa polymorphism can influence ADCC activity of NK cells, ADCC activity of NK cells with FcγRIIIa-158V/V is higher than that of NK cells with FcγRIIIa-158V/F.

Optimized protocols for generation of cord blood-derived cytokine-induced killer/natural killer cells.

The efficacy of various combinations of stem cell factor (SCF), FLT3 ligand, interleukin (IL)-2, IL-7 and IL-15 to induce and expand cord blood-derived cytokine-induced killer (CIK) cells was investigated. There were three treatment groups: group A: SCF combined with IL-2, IL-7 and IL-15; group B: SCF, FLT3 ligand combined with IL-2, IL-7 and IL-15, and group C: IL-2, IL-7 and IL-15, the control group. Proliferation rates of CD3(+)CD56(+) CIK cells and CD3(-)CD56(+) natural killer (NK) cells were highest in group B; expansion of CIK cells increased 796.1 ± 278.5-fold, and that of NK cells increased 36.6 ± 3.5-fold. All expanded cord blood-derived CIK/NK cells showed cytotoxic activity against the K562 cell line. Interestingly, the cytotoxicity of group A was highest and significantly higher than that of other groups. These protocols might provide an alternative choice for CIK/NK cell expansion.

[Fcγ receptorIIIa polymorphism in healthy children and those with hematological malignancies].

Fcγ receptorIIIa (FcγRIIIa) polymorphism was considered to influence clinical response to therapeutic monoclonal antibody (MAb) against cancer, which is suggested to affect MAb binding and MAb-dependent NK cell-mediated cytotoxicity. The purpose of this study was to examine the FcγRIIIa gene polymorphisms in healthy children and in children with hematological malignancy, and to explore its possible effect on MAb in children with hematological malignancies. 43 healthy children (H) and 20 pediatric patients with hematological malignancies (HM) were enrolled in this study. DNA was isolated from peripheral blood, and then nest-polymerase chain reaction-restriction fragment length polymorphism (nest-PCR and PCR-RFLP) was used to determine the FcγRIIIa-158 genotypes in each groups of subject, digested fragments were subjected to electrophoresis on 15% PAGE. The results showed that there were a higher frequencies of FcγRIIIa-158V/F in H and HM group (72.1% and 75.0% respectively), the frequencies of FcγRIIIa-158V/V were 27.9% and 25.0% in H and HM group respectively, but there was no FcγRIIIa-158F/F in the two groups. No significant difference in distribution of the FcγRIIIa-158 genotype was found between HM and H groups (p > 0.05). It is concluded that FcγRIIIa-158V/F is more frequent, while FcγRIIIa-158V/V is less, but FcγRIIIa-158F/F is very rare in both groups. No significant difference of FcγRIIIa polymorphism distribution is found between healthy and hematological malignancy groups.

[Distribution and interaction of bone marrow mesenchymal stem cells and cord blood CIK/NK cells infused via different ways at different time periods in NOD/SCID mice].

The study was aimed to explore the distribution and interaction mechanism of human bone marrow mesenchymal stem cells (MSC) and cord blood cytokine-induced killer (CIK)/natural killer (NK) cells infused via different ways at different times in NOD/SCID mice. 5 microl 1, 1'-dioctadecyl-3, 3, 3', 3'-tetramethylindocarbocyanine perchlorate (DiI) dye(red) was added in suspension of MSC per ml, and 1 microl carboxyfluorescein diacetate, succinimidyl ester(CFDA SE) dye(green) was added in suspension of CIK/NK cells per ml. The amounts of MSC and CIK/NK cells infused in each 6 NOD/SCID mouse were 1 x 10(6) (0.1 ml) and 1 x 10(7) (0.1 ml) respectively. All mice were divided into 4 groups, each group consisted of 6 mice. Group A: MSC (intravenous infusion, iv) + CIK/NK cells (iv) at the same time, group B: MSC (iv) + CIK/NK cells (iv) at 48 hours after infusion of MSC; group C: MSC (intramedullary infusion, im) + CIK/NK cells (iv) at the same time; group D: MSC (im) + CIK/NK cells (iv) at 48 hours after infusion of MSC. 3 NOD/SCID mice were sacrificed per batch at 24 hours and 48 hours after infused CIK/NK cells. Frozen sections of liver, spleen, lung and kidney were prepared, and then followed by counting the amounts of red and green fluorescence cells under fluorescence microscope, and calculating the ratio of MSC to CIK/NK cells for reflecting the interaction of MSC and CIK/NK cells in mice, and for showing the suppressive intensity of MSCs on CIK/NK cells. The results showed that the sums of average ratios of MSC to CIK/NK cells in lung, liver and spleen of group A and B were higher than that in group C and D at 24 hours and 48 hours respectively after infusing CIK/NK cells. The sum of average ratios of MSC to CIK/NK cells in group A was slightly higher than that in group B at 24 hours and 48 hours after infusing CIK/NK cells, but there was no significant difference between them. The sum of average ratios of MSC to CIK/NK cells in lung, liver and spleen in group C was slightly lower than that in group D at 24 hours after infusing CIK/NK cells, but reversed at 48 hours later and there was no significant difference between them. The sums of average ratios of MSC to CIK/NK cells in lung, liver and spleen in group A, B, C and D were all higher than those in kidney at 24 and 48 hours respectively after infusing CIK/NK cells. It is concluded, the MSC and CIK/NK cells may interact if they are infused via the same way and at the same time, the location where the suppression of MSC on CIK/NK cells occur in vivo may be reticulo-endothelial systems in lungs and livers.

[Mesenchymal stem cells for treatment of steroid-resistant chronic graft-versus-host disease].

OBJECTIVE: To assess whether treatment with mesenchymal stem cells (MSCs) is an effective adjunct therapy for refractory extensive chronic graft-versus-host disease (GVHD) resistant to conventional therapy. METHODS: 12 patients with steroid-resistant extensive chronic GVHD were treated with MSCs. One patient received one dose, 10 received two doses, and the remaining three doses. The MSCs were obtained from HLA-identical sibling donors (n = 14), haploidentical donors (n = 2), unrelated mismatched donor (n = 1) and third-party HLA-mismatched donors (n = 7). Of the 11 patients treated with multiple infusions, 5 received cells derived from two donors. The median first dose of MSCs was 1.0 (0.4-2.1) x 10(6)/kg, the median second dose was 1.2 (0.8-1.9) x 10(6)/kg , and the third dose in one patient was 1.1 x 10(6)/kg. Meanwhile the proportion of CD3+, CD4+, CD8+, CD19+, CD4+, CD25+, FOXP3+, FOXP3+ CD4+ and FOXP3 + CD25+ was determined with double fluorescent-labeled antibodies and flow cytometry before and 4 weeks after the MSCs infusion. RESULTS: No patients had side-effects during or immediately after the infusions of MSCs. After a treatment course of one to three doses, 3 patients had complete response( CR), 6 showed partial response (PR) and 3 did not respond; the total effective rate was 75% (9/12). Complete resolution was seen in the involvement of skin (3/12), lung (1/3), joints (1/5), liver (3/10), oral cavity (4/12) and eye (2/7). Response rate was not related to donor HLA-match. 3 CR patients discontinued all of the immunosuppressive agents without relapse 100 to 292 days after the MSC infusion and 6 PR patients taped all immunosuppressive agents after 60 to 79 days. Mean follow-up period was 1152 (795-1914) days, leukemia free survival rate was 91.7% (11/12) and the overall survival rate was 75% (9/12). The ratio of CD4/CD8 and the proportion of regulatory T cells were significantly higher than that before MSCs treatment. CONCLUSION: Third-party MSCs were as effective as HLA-identical or haploidentical cells. This finding has practical implications and suggests that third-party cells can be prepared and stored frozen to be used for steroid-resistant extensive chronic GVHD therapy. It is concluded that MSCs may prevent the lethal cGVHD after allogeneic hematopoietic stem cell transplantation and raise the survival rate by increasing the ratio of CD4/CD8 and proportion of regulatory T cells in vivo.

[Effect of mesenchymal stem cells on expression of CD69 in cord blood CIK/NK cells and quantity ratio of T regulatory cells in CIK/NK cell culture].

This study was purposed to explore the effect of bone marrow derived mesenchymal stem cells (MSCs) on the expression of CD69 on cytokine-induced killer (CIK)/natural killer (NK) cells derived from cord blood and on the quantity ratio of CD4+CD25+ T regulatory cells in CIK/NK cell culture system using Transwell non-contact cell culture system. The experiments were divided into two groups: Transwell non-contact culture and mixture culture. The ratio of MSC to CIK/ NK cells was 1:20, 1:50 and 1:100. In mixture culture groups, MSC and CIK/NK cells were co-cultured by together contact as the same ratio of Transwell non-contact culture groups. The expression of CD69 on CIK/NK cells, as well as the quantity ratio of CD4+CD25+ T regulatory cells in CIK/NK cell culture were evaluated by flow cytometry. The results showed that the expression of CD69 on CIK/NK cells in experimental groups were significantly lower than that in control group (p<0.001). As to Transwell groups, CD69 expression on the CIK/NK cells at 1:20 ratio of MSC and CIK/NK was significantly lower than that at 1:50 and 1:100 ratio. There were no differences in the expression of CD69 on CIK cells in mixture groups with various MSC ratios, whereas the expression of CD69 on NK cells at 1:20 ratio was significantly lower than that at 1:50 and 1:100. The quantity ratio of CD4+CD25+ cells in CIK/NK cell culture system of experimental groups with MSC co-culture was significantly higher than that in control. As to Transwell groups, the ratio of CD4+CD25+ cells in CIK/NK cell culture system at 1:20 and 1:50 was significantly higher than that at 1:100. The quantity ratio of CD4+CD25+ cells in CIK/NK cell culture system showed significant differences in various mixture groups. As to 1:20 ratio the amount of CD4+CD25+ cells in CIK/NK cell culture system of mixture groups was significantly higher than that in Transwell groups, while there were no differences of the quantity ratio of CD4+CD25+ cells in CIK/NK cell culture at 1:50 and 1:100. It is concluded that either by non-contact Transwell or mixed co-culture, the MSC can suppress the activation of allogeneic CB-CIK/NK cells, which maybe relate to up-regulating the ratio of CD4+CD25+ T regulatory cells in CIK/NK cell culture system in dose-dependent manner.

[Relationship between cellular immune function during conditioning and graft rejection in patients with beta-thalassemia major].

OBJECTIVE: To analyze the relationship between cell-mediated immune function during conditioning and graft rejection in patients with beta-thalassemia major. METHODS: Allogeneic hematopoietic stem cell transplantation was performed in 25 children with beta-thalassemia major and 11 with acute leukemia group. The percentages of T lymphocytes and natural killer (NK) cells in peripheral blood of these patients were detected with dual color immunofluorescence on day -10 (before conditioning) and day -5 (after conditioning), and the relationship between the cellular immune function and graft rejection was analyzed. RESULTS: All the patients with acute leukemia showed engraftment. The rate of graft rejection was 34.8% in the patients with beta-thalassemia major. Compared with the leukemic patients, the patients with beta-thalassemia showed significantly increased percentage of CD3(+)CD8(+) T lymphocytes before and after the conditioning (P<0.05). The percentage of CD3(-)CD56(+) NK cells increased significantly in patients with beta-thalassemia major after the conditioning (P<0.05), but decreased markedly after conditioning in the leukemic patients (P<0.05). In patients with beta-thalassemia major and graft rejection, the CD3(-)CD56(+) cell phenotype was predominant after conditioning but remained unchanged in those with engraftment. CONCLUSION: CD3(-)CD56(+) NK cells are probably associated with graft rejection in patients with beta-thalassemia major, and may serve as an index for predicting graft rejection following allogeneic hematopoietic stem cell transplantation.

[Unrelated allogeneic umbilical cord blood transplantation: present status, problems and countermeasures].

As unrelated allogeneic umbilical cord blood transplantation (UCBT) has been developed for 20 years already since 1988, more than ten thousands cases have cumulatively undergone UCBT over the world. A huge number of clinical data confirmed that UCBT had unique characters with low rate of severe GVHD. The efficacy and data on TRM, relapse and EFS of allogeneic UCBT with HLA 0-1 mismatched are similar to those in HLA matched BMT. UCBT has become the optimal choice for source of hematopoietic stem cells for allogeneic stem cell transplant especially when HLA-matched or haploidentical donors are not available in time. In most developed countries, unrelated allogeneic UCBT developed successively, and in recent years HLA mismatched UCBT with double units performed in adults increased even more rapidly than in children. Another recent trend of UCBT has been extending to treat some non-malignant but refractory diseases in pediatrics, such as severe combined immunodeficiency, thalassemia major, bone marrow failure syndrome and metabolic disorders. The clinical successful practice of double units for cord blood transplantation inspires to ponder over questions remaining mystery. What is the conflict like between two mismatched donor cells in vivo, which does not spoil the whole transplantation but enable the patient to be engrafted successfully without any increment of the dosage by the sum of two doses together? How can they both be taken at the same time firstly by the recipient, but why does only one predominate later? What are the factors enable the donor cells of the winner to sustain? With the references of the international experiences, how to solve the clinical encountered problems, perspective of unrelated allogeneic UCBT and proper strategies to be enacted are reviewed.

[Effect of intra-bone marrow infusion of allogeneic mesenchymal stem cells on reconstruction of marrow mesenchymal stem cells in rat HSCT models].

This study was aimed to investigate the effect of intra-bone marrow (IBM) injection of allogeneic mesenchymal stem cells (MSCs) on reconstruction of bone marrow MSCs (BM-MSCs) in rats that received hematopoietic stem cell transplantation (HSCT), and to detect the donor MSCs in the hosts for clarifying the effect mechanism of donor MSCs. Wistar female rats conditioned with lethal dose 60Co gamma-ray irradiation were co-transplanted with F344 female fetal and neonatal peripheral blood (FNPB) and BrdU-labeled MSCs separated from bone marrow mononuclear cells of F344 male rats. The donor MSCs were infused by IBM injection in bilateral tibia or intravenous injection (IV), while the FNPB were all via IBM route. The survival rate, engraftment level of HSCs and recovery of BM-MSCs of recipients were monitored. The ratio of BrdU-labeled MSCs in recipient rats was calculated by immunofluorescence assay (IFA) and the Y chromosomes were examined by PCR. The results showed that the recipient rats of the two co-transplantation groups were all alive at day 60 after transplantation. There was no significant difference between these two groups on the survival rates or the engraftment levels of HSCs, but each of them was much better than that of the FNPB group. At day 30 after transplantation, the proliferation ability of recipients' BM-MSCs was still below normal, while that of the FNPB (IBM)+MSC (IBM) group was the best of all the experiment groups (p<0.01). At 60 days, the donor MSCs coexisted with host MSCs in only a few recipient rats examined by IFA, while the Y chromosomes could be detected in all the recipient rats in the two cotransplantation groups. It is concluded that the infusion of allogeneic MSCs can accelerate the recovery of HSCT recipients' BM-MSCs. The IBM route is safe and more effective than intravenous infusion.