A complete oral regimen for induction therapy of patients with high-risk APL: An oral etoposide instead of intravenous infusion for cytoreductive chemotherapy.

There is an urgent need for an oral, efficient and safe regimen for high-risk APL under the pandemic of COVID-19. We retrospectively analysed 60 high-risk APL patients. For induction therapy (IT), in addition to all-trans retinoic acid (ATRA) and oral arsenic (RIF), 22 patients received oral etoposide (VP16) as cytotoxic chemotherapy (CC), and 38 patients received intravenous CC as historical control group. The median dose of oral VP16 was 1000 mg [interquartile rage (IQR), 650-1250]. One patient died during IT in the control group, 59 evaluable patients (100%) achieved complete haematological remission (CHR) after IT and complete molecular remission (CMR) after consolidation therapy. The median time to CHR and CMR was 36 days (33.8-44) versus 35 days (32-42; p = 0.75) and 3 months (0.8-3.5) versus 3.3 months (2.4-3.7; p = 0.58) in the oral VP16 group and in the control group. Two (9.1%) and 3 (7.9%) patients experienced molecular relapse in different group respectively. The 2-year estimated overall survival and event-free survival were 100% versus 94.7% (p = 0.37) and 90.9% versus 89.5% (p = 0.97) respectively. A completely oral, efficient and safe induction regimen including oral VP16 as cytoreductive chemotherapy combined with ATRA and RIF is more convenient to administer for patients with high-risk APL.

Characteristics and outcomes of COVID-19 in patients with plasma cell dyscrasias during the first Omicron wave in Beijing since December 2022: a retrospective study at a National Clinical Research Center for Hematologic Disease.

The wave of coronavirus disease 2019 (COVID-19) with Omicron variant reached its first peak in Beijing, China in December 2022. We delineated characteristics and factors associated with adverse outcome of patients with plasma cell dyscrasias (PCDs) and COVID-19 during the first month of the wave. A total of 104 patients with a median age of 65 years were included in the study, with multiple myeloma (74%, n=77) and primary Immunoglobulin light chain amyloidosis (16.3%, n=17) being the two most common disease. Overall, severe or critical COVID-19 was developed in 18 (17.3%) patients, with a total all-cause mortality rate of 4.8% (n=5). The vaccination coverage was 41% and 48.1%, before and during the upsurge of Omicron, respectively, calling for the improvement of vaccination in PCD patients. Multivariable analysis revealed that age was the only independent risk factors (OR=1.14, 95% CI: 1.06-1.26, p = 0.002) associated with the development of severe or critical disease. Among patients with severe or critical group, low levels of albumin (HR=18.29; 95% CI: 1.82-183.44, p = 0.013) and high levels of lactic dehydrogenase (LDH) (HR=0.08; 95% CI: 0.01-0.65, p = 0.018) were associated with longer time to negative conversion of COVID-19.

Patients with AML-MRC benefit from decitabine in combination with low-dose G-CSF, cytarabine and aclarubicin: A single center cohort study.

Patients with acute myeloid leukemia with myelodysplasia-related changes (AML-MRC) are insensitive to conventional chemotherapy and, therefore, have a poor prognosis. To evaluate the clinical efficacy and safety of low-dose decitabine in combination with small-dose CAG regimen (D-CAG regimen) in treating AML-MRC, a total of 80 patients with newly diagnosed AML-MRC from September 2015 to January 2020 in our center were included in the study. Amongst these patients, 43 and 37 patients received two courses of the D-CAG and CAG regimens, respectively. The complete remission (CR) and complete remission with incomplete blood count recovery (CRi) rate in the D-CAG group was higher than that of the CAG group (62.2% vs. 48.8%, P = 0.013). Among patients with less than 9 months of myelodysplastic syndrome (MDS) history and poor karyotypes, the (CR+CRi) rate of the D-CAG group was statistically higher than that of the CAG group. Except for patients receiving hematopoietic cell transplantation, among patients with less than 9 months of MDS history, the D-CAG group showed a better probability of overall survival than the CAG group did. In conclusion, patients with AML-MRC may benefit from the D-CAG regimen as an induction therapy, especially patients with less than 9 months of MDS history or with poor karyotypes.

PML-RARA transcript levels at the end of induction therapy are associated with prognosis in non-high-risk acute promyelocytic leukaemia with all-trans retinoic acid plus arsenic in front-line therapy: long-term follow-up of a single-centre cohort study.

Despite the high cure probability for acute promyelocytic leukaemia (APL), a minority of patients will relapse and the risk factors for relapse are unclear. We retrospectively analysed 212 patients who were diagnosed with non-high-risk APL and received all-trans retinoic acid (ATRA) plus arsenic as front-line therapy at Peking University Institute of Hematology from February 2014 to December 2018. A total of 176 patients (83%) received oral arsenic (realgar-indigo naturalis formula) plus ATRA, 36 patients (17%) received arsenic trioxide plus ATRA and 203 patients were evaluable for relapse. After a median (range) follow-up of 53·6 (24·3-85·4) months, two patients had molecular relapse and eight had haematological relapse. A promyelocytic leukaemia/retinoic acid receptor alpha (PML-RARA) transcript level of ≥6·5% at the end of induction therapy was associated with relapse (P = 0·031). The 5-year cumulative incidence of relapse, event-free survival and overall survival were 5·5%, 92·3% and 96·3% respectively. In conclusion, the present long-term follow-up study further confirmed the high cure probability of ATRA plus oral arsenic as front-line therapy for non-high-risk APL and showed that the PML-RARA transcript level at the end of induction therapy was associated with relapse.

Interferon-α as maintenance therapy can significantly reduce relapse in patients with favorable-risk acute myeloid leukemia.

To evaluate the efficacy of interferon-α (IFN-α) as maintenance therapy in patients with favorable-risk acute myeloid leukemia (AML), this retrospective study enrolled 84 patients with favorable-risk AML: 42 patients who received IFN-α maintenance therapy and 42 patients who did not (control). The median follow-up time and duration of IFN-α treatment was 26 (6-54) months and 18 (2-24) months, respectively. The 4-year estimated relapse-free survival (RFS) after the last consolidation chemotherapy was 86.8% (95% confidence interval (CI), 75.8-97.8%) in the IFN-α group and 55.7% (95% CI, 37.2-74.3%) in the control group (p=.007). The 4-year estimated overall survival was 94.4% (95% CI, 86.8-102%) and 76.4% (95% CI, 61.9-90.9%) in IFN-α and control groups, respectively (p=.040). The Cox regression analysis showed that IFN-α treatment was the only independent factor affecting RFS (p=.004). Maintenance therapy with IFN-α may prevent relapse in favorable-risk AML after consolidation chemotherapy.

Both the subtypes of KIT mutation and minimal residual disease are associated with prognosis in core binding factor acute myeloid leukemia: a retrospective clinical cohort study in single center.

Core binding factor acute myeloid leukemia (CBF-AML), including cases with KIT mutation, is currently defined as a low-risk AML. However, some patients have poor response to treatment, and the prognostic significance of KIT mutation is still controversial. This study aimed to explore the prognostic significance of different KIT mutation subtypes and minimal residual disease (MRD) in CBF-AML. We retrospectively evaluated continuous patients diagnosed with CBF-AML in our center between January 2014 and April 2019. Of the 215 patients, 147 (68.4%) and 68 (31.6%) patients were RUNX1-RUNX1T1- and CBFB-MYH11 positive, respectively. KIT mutations were found in 71 (33.0%) patients; of them, 38 (53.5%) had D816/D820 mutations. After excluding 10 patients who died or were lost to follow-up within a half year, 42.0% (n = 86) of the remaining 205 patients received allogeneic hematopoietic stem cell transplantation (allo-HSCT). An MRD > 0.1% at the end of two cycles of consolidation predicted relapse (P < 0.001). Multivariate analysis showed that D816 or D820 mutations and MRD > 0.1% at the end of two cycles of consolidation were independent adverse factors affecting relapse-free survival (RFS) and overall survival (OS). Allo-HSCT could improve RFS (74.4% vs. 34.6%, P < 0.001) and OS (78.1% vs. 52.3%, P = 0.002). In conclusion, high-risk CBF-AML patients must be identified before treatment. D816/D820 mutation, MRD > 0.1% at the end of two cycles of consolidation chemotherapy predicted poor survivals, and allo-HSCT can improve the survival of properly identified patients.

The loss or absence of minimal residual disease of <0·1% at any time after two cycles of consolidation chemotherapy in CBFB-MYH11-positive acute myeloid leukaemia indicates poor prognosis.

No consensus has been reached on the relationship between CBFB-MYH11 copies and prognosis. Of 1525 acute myeloid leukemia (AML) patients, 58 with CBFB-MYH11-positive AML (16/58 patients with c-kit mutation) were retrospectively analyzed with a median follow-up duration of 29.8 (range: 4.8-74.4) months. Of these, 25/58 (43.1%) patients underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT), 10 of whom had the c-kit mutation. Of the 33 patients who did not undergo allo-HSCT, recurrence in patients with CBFB-MYH11/ABL level >0.1% at any time after two consolidation cycles was significantly higher than in patients with CBFB-MYH11/ABL level <0.1% (61.9% vs. 0%, P = 0.001); further, the 3-year relapse-free survival (RFS; 31.4% vs. 100%, P = 0.004) and event-free survival (EFS; 33.1% vs. 100%, P = 0.004) were significantly decreased in patients with CBFB-MYH11/ABL level >0.1% at any time after two consolidation cycles. The 3-year RFS and EFS rates were lower in patients who did not receive allo-HSCT than in those who did (31.4% vs 84.6%, P = 0.000; 31.4% vs. 80.8%, P = 0.001). CBFB-MYH11-positive AML patients with CBFB-MYH11/ABL level >0.1% at any time after two cycles of consolidation had poor prognoses, and allo-HSCT could improve their survival.

Detection of measurable residual disease may better predict outcomes than mutations based on next-generation sequencing in acute myeloid leukaemia with biallelic mutations of CEBPA.

Acute myeloid leukaemia (AML) patients with biallelic mutations of CEBPA (bi CEBPA) have a 30-50% relapse rate. This study established the value of mutations based on next-generation sequencing (NGS) and multiparameter flow cytometric measurable residual disease (MFC-MRD) detection and compared the outcomes. From 2014 to 2018, 124 newly diagnosed bi CEBPA AML patients were treated. The median age was 37·5 (16-69) years. The 3-year cumulative incidence of relapse (CIR), relapse-free survival (RFS) and overall survival (OS) were 33·0%, 64·7% and 84·3%, respectively. Patients without additional mutations and with GATA2 mutations were defined as 'NGS low risk', which was the only favourable independent factor for CIR and RFS of pretreatment parameters. Patients with sustained positive MRD after two consolidation cycles and MRD negative losses at any time were defined as 'MRD high risk', which was the only poor independent factor for CIR, RFS and OS, including pretreatment and post-treatment parameters. In CR2 and non-remission patients who underwent allo-HSCT, superior OS was achieved. We conclude that NGS low risk was a favourable factor in the analysis of pretreatment parameters. MRD risk stratification was an independent prognostic factor in pretreatment and post-treatment parameters. Relapsed patients still have a favourable outcome followed by allo-HSCT.

[The value of the current diagnostic criteria of pulmonary invasive fungal infection after allogeneic hematopoietic stem cell transplantation].

OBJECTIVE: To analyze the practicality of current diagnostic criteria of invasive fungal infection (IFI) in patients with hematologic diseases/malignant tumors, so as to enhance the recognition of characteristics of pulmonary IFI after allogeneic hematopoietic stem cell transplantation (allo-HSCT). METHODS: The clinical features of 51 cases with IFI after allo-HSCT were analyzed retrospectively. RESULTS: Pulmonary IFI accounted for 42.1% (51/121) of the whole infectious pneumonia diagnosed among the patients admitted during the study. One (2.0%) case was proven diagnosis; 24 (47.1%) were probable diagnosis and 26 (51.0%) were possible diagnosis. The using of immuno-suppressors and corticosteroids, and the presence of graft-versus-host disease (GVHD) were the main host factors. The patients with two or more host factors simultaneously accounted for 66.7% (34/51) of all pulmonary IFI patients. Totally 94.1% (48/51) of the patients with pulmonary IFI presented nodules and/or patches as the main features in high resolution computed tomography (HRCT) scanning. The positive rates of fungal antigen detection were 58.6% for G test and 33.3% for GM test, which were relatively high. Twenty patients (39.2%) showed decrease of arterial partial pressure of oxygen and hypoxia in blood-gas analysis. CONCLUSIONS: For the diagnosis of pulmonary IFI post allo-HSCT, the administration of immuno-suppressors and corticosteroids, and the presence of GVHD were the main host factors. Nodules and/or patches were the main features in HRCT image. Fungus antigen detection is the main tool to support clinical diagnosis.

[Biological characteristics of wharton's jelly derived mesenchymal stem cells after cryopreservation].

Aim of this study was to explore the effects of cryopreservation on biological characteristics of wharton's jelly derived mesenchymal stem cells (WJ-MSC), and to provide experimental evidence for clinical applications and the establishment of WJ-MSC bank. Primary WJ-MSC were produced by umbilical cord tissue culture in vitro. Fifth passage of WJ-MSC acquired by continuous cell culture were mixed with cryoprotectants, frozen in -80°C refrigerator and stored in liquid nitrogen. After the cryopreserved WJ-MSC were thawed, the first passage of WJ-MSC was obtained through cell culture and was taken as the 1st preserved passage (PP1). Thus, PP2-PP15 WJ-MSC were obtained by continuous cell subculture. The 1st control passage (CP1) to 15th passage (CP15) represented the 6th passage to 21st passage WJ-MSC acquired by subculturing in non-cryopreserved group. The biological characteristics of WJ-MSC from cryopreserved and control group, including the recovery rate of nucleated cells, trypan blue exclusion, CCK-8 activity, cell apoptosis, cell adherence, proliferation index, cell surface antigen, cell cycle and the capacities of induced differentiation into adipocyte, osteoblast and neuron, were detected and compared. The results indicated that the recovery rate of nucleated cells of cryopreserved WJ-MSC was 98.2%, trypan blue exclusion rate was 94.3%, CCK-8 activity was 91.4%, apoptotic rate was 3.9%, and the adherence rate was 92.6%. There was a statistically significant difference in proliferation index between PP1 and CP1 (P < 0.05), but there were no statistically significant differences between PP2-PP15 and their corresponding controls. The subculture cells highly expressed CD29, CD44, CD71, CD73, CD90, CD105, CD166 and HLA-ABC, and lowly expressed CD34, CD45 and HLA-DR. The expressions of above-mentioned surface antigens were not different statistically between two groups. The proliferation latency and logarithm proliferation of the subculture cells between two groups were also not different. After induced differentiation into adipocyte, osteoblast and neuron, the staining with oil red O, alkaline phosphatase and neuron-specific enolase was performed respectively, and the positive degrees were not clearly different macroscopically between two groups. Relatively high levels of triglyceride, alkaline phosphatase, and neuron-specific enolase in relevant cells could be detected, but had no significant differences between two groups. It is concluded that some WJ-MSC (< 10%) are damaged after cryopreservation, and the biological characteristics of WJ-MSC in cryopreservation group keep constant, as compared with that in non-cryopreservation group.

[Morphologic diagnosis and onset characteristics of acute leukemia: a retrospective analysis of 233 cases in 10 years].

The objective of this study was to evaluate the value of morphologic diagnosis for acute leukemia (AL), to explore the relation of morphologic diagnosis with immunology, cytogenetics and molecular biology diagnosis of AL and to analyze the onset characteristics of AL in 10 years. The samples of bone marrow and peripheral blood from 233 newly diagnosed cases of AL were collected during 2001-2011 years; the morphologic examination and immunologic, cytogenetic and molecular biologic examination (ICM) were carried out, the consistency of morphologic diagnosis with ICM diagnosis was compared, the onset characteristics of AL was analyzed. The results showed that: (1) the consistent rate of immunology, cytogenetics, molecular biology diagnosis with morphologic diagnosis was 84.3%. The order of consistent rat was AUL, M0 < M1 < HAL < M4 < M2 < M3 < M5 < ALL < M6, M7, AP; (2) Misdiagnosis always occurred among AUL, M0, M1, ALL and HAL or among M2a, M3v, M4 and M5. (3) In 233 cases, the highest ratio of blast was observed in M1 (92.5%), while the lowest ratio of blast was observed in M2 (49.5%). (4) AL occurred more frequently in males than that in female (147:86). (5) AL occurred in patients aged from 1 to 88 years. The median age was 41.5 for AUL, 40.8 for M0, 43.4 for M1, 46.3 for M2, 33.8 for M3, 42.6 for M4, 48.8 for M5, 77.3 for M6, 2.5 for M7, 65.0 for AP, 29.1 for ALL and 40.3 for HAL. (6) The number of patients in the later five years (139 cases) was significantly greater than that in the first five years (94 cases), especially the patients with M1, M2, M3, M4, and M5. It is concluded that morphologic diagnosis has important clinical value in the MICM diagnosis of AL. Attaching importance to the confusing cell morphology and onset characteristics of AL can improve the diagnostic accuracy.

Effectiveness of human mesenchymal stem cells derived from bone marrow cryopreserved for 23-25 years.

OBJECTIVE: To evaluate long-term cryopreserved human bone marrow cells (BMCs) as a source of functional mesenchymal stem cells (MSCs). METHODS: Samples of human BMCs that were cryopreserved for 23-25 years (n=20) were thawed to obtain an initial culture and a primary culture (P(0)) that was propagated through five passages (P(1)-P(5)) to obtain MSCs. Freshly collected human bone marrow samples (n=20) were used as controls for comparison of efficiency of recovery and growth characteristics of MSCs. P(3) cultures were tested for their capacity to differentiate into osteoblasts, adipocytes, and neuronal cells. Appropriate staining, immunohistochemical and biochemical methods were employed to ascertain cell type identities at different stages of culturing. RESULTS: In the initial culture, the cell adherence rate of the cryopreserved cells was significantly lower than that of controls (19.7% vs. 38.2%, p<0.05) while the relative rate of recovery of MSCs was only 48.5±8.6% in P(0). At the end of P(3), fibroblast-like cells accounted for about 95% of cells in both cryopreserved and control groups (p>0.05). These cells were positive for essential MSC surface molecules (CD90, CD105, CD166, CD44, CD29, CD71, CD73) and negative for haematopoietic and endothelial cell markers (CD45, CD34, HLA-DR). The cell growth and cell cycle patterns were similar for both groups. MSCs at P(3) from both groups had similar capacities to differentiate in vitro into osteoblasts, adipocytes, and neuronal cells. CONCLUSION: Using the methods described here, long-term (23-25 years) cryopreserved human BMCs can be successfully cultivated to obtain MSCs that have good differentiation capabilities.

[The effects of thrombopoietin on the fibrogenesis of bone marrow stromal cells in absence of megakaryocytes].

OBJECTIVE: In order to investigate whether or not thrombopoietin (TPO) could promote the fibrogenesis of bone marrow stromal cells in absence of megakaryocytes (MKs). METHODS: Improved dexter culture system with various TPO concentrations was used for ex vivo culture of bone marrow stromal cells. Relative proliferation index, the expressions of fibronectin, laminin and type IV collagen, and the systhesis of type III procollagen were detected at different time points during culture process. RESULTS: TPO stimulated the proliferation of bone marrow stromal cells. Relative proliferation index of the stromal cells increased with the TPO concentration increasing, and was not related to the exposure time. The expressions of fibronectin, laminin, and type IV collagen appeared stronger in the TPO groups than those in the control group. But the expressions of these molecules were not dependent upon the culture time. TPO could accelerate the synthesis of type III procollagen in bone marrow stromal cells, and this acceleration was unrelated to the TPO concentration. CONCLUSION: These findings suggested that TPO could stimulate the stromal cells with a consequence of increased syntheses and secretions of the extracellular matrix and collagen in absence of MKs. In other words, TPO could promote the fibrogenesis of bone marrow stromal cells without the existence of MKs.

[In vitro activity of human bone marrow cells after cryopreservation in liquid nitrogen for 21 - 25 years].

The aim of this study was to investigate the best method to preserve human bone marrow cells and the effectiveness of long term cryopreservation at -80 degrees C. The human bone marrow cells in 20 samples were firstly frozen by a programmed freezer or -80 degrees C refrigerator, and then were preserved in liquid nitrogen with DMSO-AuP (10% dimethylsulfonamide, 10% autologous plasma) or DMSO-HES-HuA (5% dimethylsulfonamide, 6% hydroxyethyl starch, 4% human serum albumin) as cryoprotectant for 21 to 25 years. They were thawed in 38 degrees C. The cell sample frozen in -80 degrees C refrigerator was frozen at a low frozen speed of 1 degrees C/min which was the same as the programmed freezer before -30 degrees C. Before detection the bone marrow cells were taken from liquid nitrogen and were thawed in 38 degrees C, then the suspension of bone marrow cells was prepared for detection. The cell morphology and recovery rate of erythrocytes, nucleocytes and platelets; the recovery rate of hematopoietic stem progenitors cells, as well as mesenchymal stem cells were determined. The results showed that the protective effectiveness of DMSO-HES-HuA was better than DMSO-AuP. The mature erythrocytes were destroyed lightly [(3.5 +/- 1.5)% versus (12.6 +/- 4.8)%], the hemolysis rate was lower [(3.3 +/- 1.6)% versus (23.1 +/- 5.1)%]. Osmotic fragility of erythrocytes in the former was not changed, but was dropped in the latter. The recovery rates of red cell, platelet, granulocyte-macrophage colony forming units and long term culture-initiating cells were higher in the former than that in the latter [(96.1 +/- 1.8)%, (70.0 +/- 9.5)%, (49.2 +/- 10.9)%, (54.2 +/- 13.8)% versus (76.3 +/- 5.6)%, (52.7 +/- 8.1)%, (43.5 +/- 12.3)%, (47.2 +/- 13.6)% respectively]. With each kind of cryoprotectant or frozen method, the frozen MSC could keep the original growth properties. With the same cryoprotectant and different frozen method, the cryopreservative effectiveness was not different. The influence of the cryoprotectant prescriptions and the frozen methods on the cryopreservative effectiveness was little. It is concluded that the human bone marrow cells with DMSO-AuP or DMSO-HES-HuA as cryoprotectant, frozen by a programmed freezer or -80 degrees C refrigerator, could be then preserved in liquid nitrogen for long time. When the preserving time was as long as 21 to 25 years, the morphology, the recovery rate and the activity of various kinds of cells were still good. The method of freezing by -80 degrees C refrigerator with 5% DMSO-6% HES-4% HuA and preserving in liquid nitrogen would be convenient, cheap and easily-manipulated for preservation of the human bone marrow cells.

[Influences of bone marrow mesenchymal stem cells in patients with acute myeloid leukemia and non-leukemia on HL-60 cells -- a comparison study].

This study was aimed to compare the influences of bone marrow mesenchymal stem cells (BMMSCs) from patients with acute myeloid leukemia (AML), AML patients with complete remission (CR) and non-leukemia patients on HL-60 cells. The HL-60 cells were divided into three groups: group of co-cultivation with BMMSCs of AML patients, group of co-cultivation with BMMSCs of AML patients with CR and group of co-cultivation with BMMSCs of non-leukemia patients. The count of HL-60 cells, the CD11b and survivin expression of HL-60 cells, the cell cycle distribution of the HL-60 cells in 3 groups were compared by flow cytometry, the morphology and differentiation rate of HL-60 cells in 3 groups were observed and compared by microscopy. The results showed that there were no differences in HL-60 cell count at five and seven days, in HL-60 distribution at the G(0)/G(1) phase, in survivin and CD 11b expressions in 3 groups. All cells of 3 groups began to mature, and the differentiation rates in 3 groups were 18.0 +/- 3, 17.0 +/- 1.3 and 19.0 +/- 2.0 respectively, therefore there were no significant differences between the 3 groups (p = 0.23). It is concluded that there is no influence of BMMSCs in 3 groups on the proliferation and differentiation of HL-60 cells.

[Comparison of biological characteristics of bone marrow mesenchymal stem cells in acute myeloid leukemia with those from non-leukemia].

This study was aimed to compare partial biological characteristics of bone marrow mesenchymal stem cells (BMMSCs) in AML patients, AML patients with complete remission (CR) and non-leukemia patients. The bone marrow (BM) MSCs were divided into 3 groups: group of MSCs from AML patients, group of MSCs from AML patients with CR, group of MSCs from non-leukemia patients. The morphologic features of MSCs were observed by light microscopy; CFU-F numbers of MSCs were counted after Wright-Giemsa staining in situ; the fusion times of MSCs were determined; the growth curves of MSCs were drawn by counting cell numbers; the immunophenotypes and cell cycle of MSCs were detected by flow cytometry; the DI values of MSCs were calculated. The results showed that the morphologic features of MSCs in 3 groups did not display difference; there was significant difference (p < 0.01) of CFU-F numbers in 3 groups, while CFU-F number of MSCs in AML group was minimal; there was significant difference of MSC fusion time in 3 groups, while fusion time of MSCs in AML group was most long; the growth curves of MSCs in 3 groups were similar; MSCs in 3 groups highly expressed CD105 and CD106, but not expressed CD45; the cell distribution ratios at phase of G(0)/G(1) for MSCs in 3 groups were 89.9 +/- 4.0%, 90.2 +/- 3.0% and 91.0 +/- 3.0% respectively; the DI values of MSCs in 3 groups were between 0.9 and 1.1. It is concluded that no significant difference of biological characteristics of the second generations of MSCs is found between those in leukemia and non-leukemia patients.

[Effects of recombinant human thrombopoietin on stromal cells in culture in vitro].

This study was aimed to investigate whether the thrombopoietin (rhTPO) may facilitate myelofibrosis or not. The modified Dexter culture system with various concentrations of rhTPO was used to culture the stromal cells in vitro; the proliferative activity of cells was detected by MTT method; the morphologic changes were observed by light and scanning electron microscopy; the staining changes of ALP, PAS, AS-D NCE and IV type collagen were observed by cytochemistry method; the changes of fibronectin, laminin and IV type collagen were assayed by immunohistochemistry method; the cell surface antigens were assayed by flow cytometry. The results indicated that rhTPO could promote the proliferation of stromal cells which was related to the concentrations of rhTPO. Proliferative activity of stromal cells increased with increasing of rhTPO concentration, and was not related to the exposure time. On day 3 stromal cells adhered to the wall, and became oval. On day 7 stromal cells turned to fusiform and scattered dispersively. On day 12 to 14 these cells ranged cyclically and became long fusiform. Cells covered 70%-80% area of bottle bottom at that time. By day 16 to 18 these cells covered more than 90% area of bottom and ranged cyclically. They displayed the same shape as fibroblasts. By light microscopy with Wrights-Giemsa staining, fibroblasts predominated morphologically, few macrophages, endothelial cells and adipose cells were found. There were no significant differences between experimental group and control group. On day 14 to 42 the adherent cells were positive with PAS staining, poorly positive with ALP and naphthol AS-D chloroacetate esterase (AS-D NCE) staining, and the difference in cytochemistry was not significant between two groups. When these cells were dyed with Masson's trichrome and Gomori's staining, neither collagen fibers nor reticular fibers were positive, but fibronectin, laminin, and collagen type IV appeared positive stronger in experimental group than those in control. The expressions of these molecules were not dependent on culture time. By scanning electron microscopy microvilli and fibers on cell surface appeared more and more, monolayer cells evolved into multilayer cells, and newly-formed fibroblasts appeared gradually as culture time prolonged. These alterations were not different among various groups. The expressions of CD34, CD45, CD105, CD106, and CD166 were not affected obviously by rhTPO. It is concluded that rhTPO had no effects on histochemical properties of stromal cells. Fiber staining and scanning electron microscopic examinations revealed that rhTPO can not facilitate fiber formation of stromal cells. But rhTPO may be able to augment the expressions of fibronectin, laminin and collagen type IV of stromal cells. Therefore it is still necessary to follow up the patients for a long time, who have received rhTPO therapy clinically.

[Comparison of different cryopreservation systems for peripheral blood stem cells].

AIM: To explore proper cryopreservative systems for hematopoietic stem cells. METHODS: Peripheral blood mononuclear cells from 20 persons were mixed with different cryopreservative agent, dimethyl suflfoxide (DMSO) or combination of DMSO and hydroxyethyl starch (HES), then cooled in -80 degrees C low temperature refrigerator (Refr) or autocontrolled programmed cryogenic system (PCS), preserved in Refr or in liquid nitrogen. GM-CFU, LTC-IC, CD34+ cells and typeran blue resistance (TBR) were assayed after different period of cryopreservation. RESULTS: The recovery rates of CFU-GM, LTC-IC, CD34+ cells and TBR in peripheral blood mononuclear cells which were cooled and preserved in Refr with 5% DMSO-6% HES were 82.2% +/- 14.7%, 83.0% +/- 12.2%, 94.2% +/- 4.3% and 97.7% +/- 3.9% respectively, significantly higher than that in Refr with 10% DMSO (P < 0.05). When cells were cryopreservated with the same cryopreservatives, there was no significantly difference of recovery rate in group of Refr and group of Refr with PCS. Meanwhile, there was not significantly difference of recovery rate among all three groups, preserved in Refr ahead of liquid nitrogen, in Refr merely, in liquid nitrogen with PCS within one year (p > 0.05). However, the recovery rate of CFU-GM, LTC- IC, CD34+ cells and TBR decreased dramatically if cells were cooled and preserved in Refr for two years. After cells were thawed, the cell activity declined gradually at room temperature if the cryopreservatives were not removed or diluted. The cell activity of 10% DMSO group was affected more than that of 5% DMSO-6% HES group. CONCLUSION: 5% DMSO-6% HES is better than 10% DMSO as cryopreservatives for hematopoietic stem cells. Refr cryopreservation is a simple and effective method if cells would be cryopreserved for less than one year. If cells would be cryopreserved for more than one year, liquid nitrogen cryopreservation should be recommended. The cryopreservatives should be diluted or removed immediately after cells were thawed.

[Influence of cryopreservation on leukemic dendritic cells derived from leukemia patients].

This study was aimed to investigate the influence of cryopreservation on biological properties and function of leukemic dendritic cells (L-DCs) derived from patients with acute or chronic leukemia. Some fresh leukemic cells were detected immediately; some were cultured immediately; some were cryopreserved in -80 degrees C with 5% DMSO-6% HES as cryopreservor. After being thawed, they were cultured. The combination of rhGM-CSF, rhIL-4, rhTNF-alpha and other cytokines were added into the culture system. 12 days later, L-DCs were assayed for morphology, immunophenotype, mixed lymphocytic reaction (MLR) and CTL cytotoxicity on autologous leukemic cells. The results showed that both fresh and cryopreserved leukemic cells obtained from patients with acute or chronic leukemia revealed typical DC morphologically by means of using combinations of cytokines in culture, but there was no significant difference between pre-or post cryopreservations. L-DCs also upregulated the expression of CD80, CD54, HLA-DR, CD1a, CD83 and CD86, and downregulated the expression of CD14, but there was also no difference as compared with L-DCs befor cryopreservation. L-DCs derived from leukemic cells were also capable of stimulating MLR and inducing CTL which could kill autologous leukemic cells obviously. It is concluded that leukemic cells, regardless of fresh or frozen, can induce L-DCs after culture with cytokine combination. The L-DCs can induce CTL targeting autologous leukemic cells, and may be used to treat MRD as immunotherapy. The induction and biological properties of L-DCs are not influenced by cryopreservation.

Purified human bone marrow multipotent mesenchymal stem cells regenerate infarcted myocardium in experimental rats.

Recent findings suggest the feasibility of cardiac repair by transplantation of bone marrow mesenchymal stem cell (MSCs). However, it remains controversial regarding which cell type is the best source for transplanting into the ischemic heart because of lack of well-defined cell markers. In this study, we investigated the in vitro and in vivo effects of the novel multipotent marrow mesenchymal stem cells (MMSCs) from human bone marrow. Pluripotent markers (Oct4, Bmi1, and Abcg2) and vascular endothelial growth factor (VEGF) were detected by RT-PCR and immunofluorescence in MMSCs. Myocardial differentiation was induced in the expanded MMSC cultures by treatment with 5-azacyline. Expressions of VEGF in the animals transplanted with MMSCs were markedly increased in comparison with the animals injected with fibroblasts or saline at both mRNA and protein levels. VEGF expression was observed in both transplanted MMSCs and recipient cardiomyocytes by immunofluorescence. Confocal immunofluorescence microscopy revealed the specific markers for cardiomyocytes and endothelial cells in transplanted MMSCs 14 days after transplantation. Vessel count was increased and left ventricular function improved post-MMSC transplantation. These results indicate that transplantation of purified MMSCs from human bone marrow upregulated VEGF expression, enhanced angiogenesis, and improved the functional recovery following myocardial infarction in rats.