[Effects of Leukapheresis on Hemostatic Function in Patients with Hyperleukocytic Leukemia].

OBJECTIVE: To analyze and compare the effects of leukapheresis on hemostatic function in patients with hyperleukocytic leukemia. METHODS: A total of 139 patients with AML, ALL and CML who underwent leukapheresis from June 2009 to February 2020 and did coagulation test before and after operation were included in this study. The clearance efficiency of each group and the difference among three groups were evaluated, as well as hemostatic function including platelet counts, coagulation indicators, CDSS score and incidence of adverse events. The difference of hemostatic function caused by leukapheresis in different leukemia patients were compared. RESULTS: After leukapheresis, the WBC counts were decreased significantly in the three groups of patients (P<0.001), and the clearance efficiency was highest in ALL patients. However, the platelet counts also were decreased significantly (AML:P＜0.001, ALL: P＜0.001, CML: P＜0.01) in the three groups of patients, particularly for acute leukemia patients with a positive correlation with WBC clearance efficiency(r=0.284). After leukapheresis, fibrinogen decreased, PT and APTT prolonged. For acute leukemia patients, higher CDSS score was related to an elevated incidence of bleeding events (P<0.05). CONCLUSION: Leukapheresis is an effective method to decrease the leukemic burden, but it is necessary to monitor the impact on hemostatic function. It is recommended to assess the CDSS socre for acute leukemia patients, in order to identify the predictive value for bleedings.

[Actions of keratinocyte growth factor in leukemic mice allogeneic umbilical cord blood cell transplantation].

OBJECTIVE: To explore the actions of keratinocyte growth factor (KGF) in leukemic mice allogeneic umbilical cord blood cell transplantation (UCBT) and elucidate its mechanism. METHODS: Peripheral blood drawn from the litters of C57BL/6 females was used as umbilical cord blood (UCB) graft. BALB/c mice were randomly divided into 7 groups (n = 12 each). The grouping was as follows. Control group 1, inoculated with leukemia. Control group 2, inoculated with leukemia at -4 d and total body irradiation (TBI) treatment. Control group 3, TBI treatment and reconstituted with 2 × 10(6) UCB-TNCs. Control group 4, injected with PBS subcutaneously, TBI treatment and reconstituted with UCB-TNCs with platelet transfusion. Control group 5, inoculated with leukemia, injected with PBS subcutaneously, TBI treatment and reconstituted with UCB-TNCs with platelet transfusion. Experiment group 1, injected with KGF subcutaneously, TBI treatment and reconstituted with UCB-TNCs with platelet transfusion. Experiment group 2, inoculated with leukemia, injected with KGF subcutaneously, TBI treatment and reconstituted with UCB-TNCs with platelet transfusion. The survival status, pathohistological changes, splenic lymphoid cell subsets and thymic output post-UCBT were compared between groups. RESULTS: The survival time of control group 1 was (11.1 ± 1.5) days and all died of leukemia. The survival time of control group 2 was (11.5 ± 2.5) days and all died of aplasia. Five of 12 mice of control group 3 survived for 100 days and 7 mice died of visceral hemorrhage. Four of 12 mice of control group 5 survived for 100 days and 8 mice died of leukemia with a survival rate of 33.3%. Nine of 12 mice of experiment group 2 survived for 100 days and 3 mice died of leukemia with a survival rate of 75.0%. The survival was prolonged in experiment group 2 mice as compared with that of control group 5 mice (χ² = 4.996, P = 0.0254). The splenic T, NK and B cell counts in control group 4 mice at +35 d were (9.32 ± 0.48) × 106, (1.59 ± 0.11) × 106 and (18.74 ± 2.01) × 106 respectively. While in group 6 mice at +35 d were (13.20 ± 1.14) × 106, (1.75 ± 0.12) × 106 and (20.36 ± 0.86) × 106 respectively. The counts of T cell and NK cell of group 6 were higher than those of group 4 (both P < 0.05). The level of signal joint T-Cell receptor excision circles (sjTRECs) in control group 4 mice was (167 ± 17) copies per 105 cells while that of experiment group 1 mice (228 ± 24) copies per 105 cells. They were higher than that of control mice (P = 0.002). CONCLUSION: Hematopoietic stem/precursor cells are abundant in full-term murine fetal peripheral blood. The infusion of KGF reduces the post-UCBT relapse of leukemia through the enhancement of thymic output.

[Detection of JAK2V617F mutation and its clinical significance in 80 patients with M2 acute myelogenous leukemia].

OBJECTIVE: To explore the prevalence and prognostic significance of JAK2V617F gene mutation in acute myelogenous leukemia M2 (AML-M2) patients. METHODS: Allele specific polymerase chain reaction (PCR) was used to detect JAK2 gene mutation. RESULTS: Of 80 de novo AML-M2 patients, 6 at the time of first diagnosis and 1 at relapse were found to have JAK2V617F gene mutation (8.8%, 7/80). Morphologically, the whole blood and bone marrow of the 7 AML-M2 patients with JAK2V617F gene mutation presented a picture of acute leukemia instead of myeloproliferative disorders. Immunophenotypically, bone marrow samples showed myelogenous linage expression. Complete remission was obtained in 4 of 5 AML-M2 patients with JAK2V617F mutation who received treatment, while one patient had no response to the treatment. Follow-up was performed in all the 5 patients, with a median survival of 18.5 months in 4 patients. CONCLUSION: JAK2V617F gene mutation, as a type-1 mutation, might not be an initial event in the pathogenesis of acute myelogenous leukemia, and its presentation does not mean a poor prognosis in de novo AML patients.

[Detection and clinical significance of JAK2 mutation in 412 patients with chronic myeloproliferative neoplasms].

OBJECTIVE: To investigate the frequency of JAK2V617F mutation in Chinese patients with chronic myeloproliferative neoplasms (MPN) and to study the relationship between JAK2V617F mutation and clinical characteristics. METHODS: JAK2V617F mutation was screened by allele-specific polymerase chain reaction (AS-PCR). RESULTS: JAK2V617F mutation was detected in 277 of the 412 patients with MPN. The frequency of JAK2V617F mutation was similar among essential thrombocythemia (ET), idiopathic myelofibrosis (IMF) and chronic myeloproliferative disorders-unclassified (MPD-U) (P > 0.05), but it was significantly lower than that in polycythemia vera (PV) (P < 0.05). The presence of JAK2V617F was found to be significantly correlative with advanced age at diagnosis (P < 0.01) and with higher hemoglobin levels and higher leukocyte counts (P < 0.05). Significant difference was found in complication of vascular events between JAK2V617 positive and negative patients (P < 0.05). JAK2V617F positive MPD-U patients were more prone to progress into typical MPN compared with JAK2V617F negative MPD-U patients. The association between abnormal karyotype and JAK2V617F was not found in cytogenetical analysis of 301 patients. CONCLUSION: The presence of JAK2V617F in MPD-U is associated with the disease development. There is a correlation between JAK2V617F mutation in MPN and advanced age, higher leukocyte counts, hemoglobin level and vascular events.

[The quantitative assay and clinical significance of JAK2V617F mutation in 131 patients with chronic myeloproliferative disorders].

OBJECTIVE: To investigate the frequency and mutational status of JAK2V617F mutation in Chinese patients with chronic myeloproliferative disorders (CMPD) and to study the relative quantification of mutated JAK2 mRNA and the clinical significance. METHODS: JAK2V617F mutation and the mutational status were screened with amplification-refractory mutation system polymerase chain reaction (ARMS-PCR), the relative quantification of mutated JAK2 mRNA was studied by using capillary electrophoresis. RESULTS: A higher prevalence of JAK2V617F in either the heterozygote or homozygote status in essential thrombocythemia (ET) was observed in elderly patients with ET (P < 0.05). The presence of JAK2V617F was found to be significantly correlated with the age at diagnosis (P < 0.05); patients with age > or = 60 years showed significantly higher JAK2 mutated RNA levels than those with age < 60 years (P < 0.05); the presence of JAK2V617F in polycythemia vera (PV) and ET was found to be significantly associated with higher hemoglobin level and higher leukocyte count (P < 0.05). In addition, higher leukocyte count was observed in homozygous ET patients than in heterozygous ET patients (P < 0.05). The frequency of JAK2V617F mutation and the prevalence of homozygote in PV patients were higher than those in ET patients (P < 0.05). The differences of JAK2V617F mRNA levels among PV, ET and chronic idiopathic myelofibrosis (IMF) were not significant. CONCLUSIONS: ARMS-PCR technique can be used to detect the frequency and mutational status of JAK2V617F mutation owing to its sensitivity and along with capillary electrophoresis, quantitative assay for mutated JAK2 mRNA, diagnosis of CMPD and judgement of prognosis become possible.

[A study of T-cell reconstitution after HLA-matched sibling bone marrow transplantation in leukemia patients].

OBJECTIVE: To study T-cell reconstitution by the assessment of T-cell receptor excision circle (TRECs) and T-cell receptor clonal repertoire after HLA-matched sibling bone marrow transplantation (MSD-BMT) in leukemia patients and try to reveal the rule of T-cells repopulation in MSD-BMT. METHODS: Real-time quantitative PCR detection of TRECs was carried out in the DNA of peripheral blood mononuclear cells from 23 leukemia patients who underwent MSD-BMT. The content of TRECs in 70 normal donor individuals was also detected to determine the normal range of TRECs in healthy subjects. Among them, 10 patients received RT-PCR to amplify 24 subfamily genes of T-cell receptor B variable (TCRBV) and five normal donors served as control. The PCR products were further analyzed with genescan to evaluate the clonality of BV subfamily and calculate the usage rate of BV families. RESULTS: The mean value of TRECs in normal donors was (3351.1 +/- 3711.1) copies/10(5) cells. There was an inverse correlation between the value of TRECs and the age of healthy subjects. Before transplantation, all the patients were detected for the number of TRECs, the mean TRECs number was (307.9 +/- 433.3) copies/10(5) cells and it was far lower than that of healthy subjects. From one month to five months after bone marrow transplantative (BMT), the TRECs levels were low and in some patients they even could not be detected. Six months later, TRECs levels increased obviously and maintained that high nearly one year. 24 months after BMT, the number of TRECs increased and reached the pretransplantation status. One patient was detected 2 m and 3 m after transplantation and found that there was a tendency of additional use of BV families and an increase of the expression of CDR3 polymorphism. 2-15 months after transplantation, in ten of the patients, there were 7-16 BV subfamilies expressing and in more than 48% the expression was polyclinic. Monoclones and oligoclones existed in 24 BV subfamilies. CONCLUSIONS: At an early stage after BMT, the number of TRECs was low and remained so for a long time. TCRBV CDR3 repertoire showed certain BV families expressing. 6 months after BMT, thymus produced certain number of naive T cells and TCRBV CDR3 repertoire showed additional use of BV families and increased expression of polymorphism.

[Prediction of T-cell immune reconstitution by investigating T cell receptor excision circle and T-cell receptor beta-chain variable region clonal repertoire in leukemia patients after allogeneic hematopoietic stem cell transplantation].

OBJECTIVE: To predict T-cell immune reconstitution by investigating T cell receptor excision circles (TREC) and T-cell receptor beta-chain variable region (TCRBV) clonal repertoire in leukemia patients after allogeneic hematopoietic stem cell transplantation (allo-HSCT). METHODS: Real-time quantitative PCR was used to detect the TREC in 43 leukemia patients undergoing matched sibling donor bone marrow transplantation (MSD BMT), matched unrelated donor (MUD) BMT, or haploidentical-stem cell transplantation (HID-SCT), and in 70 normal individuals. RT-PCR was used to amplify 24 subfamily genes of T-cell receptor beta-chain variable region (TCRBV) in 24 of the 43 patients and 5 normal donors as control. The PCR products were further analyzed by genescane to evaluate the clonality of BV subfamily, characteristics of complementarity determining region 3 (CDR3), and the usage rate in BV subfamily. RESULTS: There were (335.1 +/- 782.5) copies/10(5) cells in the 43 patients before transplantation, far lower than the normal value. The TREC values of the patients of the 3 groups all decreased obviously 3 months after transplantation. The TREC value of the MSD-BMT group recovered faster than the other two groups and reached the value before transplantation in 24 months. The recovery of TREC value in the HID-BMT group was delayed. 3 - 19 months after transplantation, the usage of TCRBV subfamilies was still restricted. There were 6 - 16 BV subfamilies expressed and 33% - 48% of them were polyclonals, the others were monoclones and oligoclones and existed in 24 BV subfamilies, no common monoclone BV subfamilies was expressed. CONCLUSION: Investigation of the TREC and TCRBV clonal repertoire showed that the number of naive T cell is lower and the usage of TCRBV subfamilies skewed 3 - 24 months after allo-HSCT. The immune deficiency of the patients undergoing HID-BMT is more prominent and consistent with the clinical process.

[Quantitative analysis of donor chimerism in adoptive immunotherapy following allogeneic hematopoietic stem cell transplantation].

OBJECTIVE: To investigate the value of sequential and quantitative analysis of donor chimerism (DC) to predict the outcome of allogeneic hematopoietic stem cell transplantation (allo-HSCT), to determine the optimal time point of adoptive immunotherapy and to estimate the efficacy of adoptive immunotherapy. METHODS: Quantitative analysis of DC was performed with multiplex PCR amplification of short tandem repeats markers (STR-PCR) and capillary electrophoresis with fluorescence detection in 84 patients who received allo-HSCT. Sequential chimerism both prior to and following adoptive immunotherapy were evaluated in 16 patients. RESULTS: Increase of mixed chimerism and decrease of DC < 90% were found in 22 of the 84 patients. Six of the 22 patients who did not receive donor lymphocyte infusion (DLI) all died of relapse. Adoptive immunotherapy was used to treat the remaining 16 patients. Before the time of relapse or graft rejection, STR-PCR indicated decrease of DC in 12 of the 16 patients, with levels ranging from 24.8% - 86.2%. A response to immunotherapy was achieved in 11 of the 16 patients (68.8%). In these patients, the value of DC increased with conversion to a predominant donor profile (> or =90%). 6 of the 11 patients converted to stable full donor chimerism (FDC) and 5 of the 11 patients to transformed stable mixed chimerism (MC) shortly after immunotherapy. All these 11 patients who responded to immunotherapy developed graft versus host disease (GVHD). While in the patient without response, the level of DC decreased persistently or declined after a transient increase. Three patients without response received second DLI but still failed to response. CONCLUSION: The results demonstrate that sequential and quantitative monitoring of DC can identify the patients who have high risk of relapse or graft failure and can be used to guide adoptive immunotherapy at early stage to improve the response of immunotherapy in those patients who undergo cytogenetic or molecular relapse. Furthermore the serial and quantitative detection of DC has been shown to be a valuable tool to evaluate early the efficacy of treatment. As well, it can present a rational basis for treatment intensification in patients who did not respond to first-line adoptive immunotherapy treatment.

[Effects of Simvastatin on Expression of Multidrug Resistance Gene and Protein of SHI-1 Cells].

OBJECTIVE: To investigate the effects of simvastatin(SIM) and serum free medium(SFM) on the expression of multidrug resistance gene(MDR1) and protein of SHI-1 cells. METHODS: Trypan blue exclusion assay was used to detect the proliferation level and viability of SHI-1 cells after treatment with SIM and culture in SFM; The multi-drug resistant protein p-gp was measured by flow cytometry after culture in SFM for 1 to 3 days and treatment with various concentration of simvastatin. The effect of SFM culture and SIM treatment on the expression of MDR1 trascript was detected by qPCR; ELISA was used to measure the change of cellular cholesterol after culture in SIM and SFM. Chemosensitivity assay was performed after treatment with SIM for SHI-1 cells. RESULTS: Compared with control group, the growth of SHI-1 cells cultured in SFM decreased in a time-dependent manner. The growth-inhibitory effect was markedly increased when SHI-1 cells were treated with SIM and SFM. The mRNA level of MDR1 gene decreased after SIM treatment or/and culture in SFM. P-gp protein was downregulated in SHI-1 cells cultured in SFM or/and treated with SIM. The cellular cholesterol level increased when the cells were cultured in SFM. Total cellular cholesterol level decreased in SHI-1 cells treated with SIM and cultured in SFM. Chemosensitivity assays found that pre-treatment with SIM could increase the cytotoxicity of DNR to SHI-1 cells. CONCLUSION: Culture with SIM and SFM can downregulate the expression of MDR1 gene and p-gp protein in SHI-1 cells. SIM also can enhance the chemotherapeutic sensitivity of SHI-1 cells.

Comparison of SPE, IFE, and FLC in Monitoring Patients with Multiple Myeloma After Autologous Stem Cell Transplantation.

Conventionally, serum protein electrophoresis (SPE) and serum immunofixation electrophoresis (IFE) are used as primary methods to diagnose and monitor multiple myeloma (MM). Recently, serum-free light chain (FLC) assay has been incorporated into hematological screening programs for myeloma. The purpose of this study is to compare the performance of the three methods in monitoring MM patients after autologous stem cell transplantation (ASCT). SPE, serum IFE and serum FLC assay were performed on 38 MM patients who underwent ASCT. In total, four patients had unexpected protein bands (UPBs) and 13 patients had relapsed after ASCT. Our results indicate that IFE is more sensitive than SPE and FLC assay in detection of UPBs and relapse. The results of IFE may provide useful information in advance of patient relapse.

[Sequential and quantitative analysis of chimerism after non-myeloablative stem cell transplantation].

OBJECTIVE: To investigate the exact kinetics of donor chimerism (DC), outcome of mixed chimerism (MC) and prognostic role of chimerism in the evaluation of engraftment, disease relapse, GVHD and long term survival after nonmyeloablative stem cell transplantation (NST). METHODS: 18 patients who received HLA compatible NST were evaluated. Peripheral blood and bone marrow were collected before and after transplantation at different time. DNA was extracted using QIAmp blood mini kit. Nine different STR markers were co-amplified in a single reaction by commercial AmpF/STR profiler plus PCR amplification kit. Separation of the PCR products and fluorescence detection were performed with ABI prism 310 genetic analyzer with capillary electrophoresis. Genescan and genotype software were used for size calling and quantification of peak areas. The formula to calculate donor chimerism values was based on different allelic distribution types between the donor and recipient. RESULTS: (1) Serial STR-PCR analysis revealed that donor chimerism became dominant (DC > 60%) by day 8; it preceded the detection of hematologic engraftment by an average of 4 days. It was also shown that chronic myeloid leukemia (CML) patients frequently had more delayed donor engraftment as compared with patients of acute leukemia or nonmalignant hematological diseases because the pretransplantation immune status of these two kinds of patients was different. (2) After NST, chimeric status had a process of conversion from the mixed chimerism (MC) to full donor chimerism (FDC). (3) The incidence of graft versus host disease (GVHD) of FDC group was higher than that of MC group (90.0% vs 62.5%). The average time between establishment of FDC and appearance of GVHD was 9 days. (4) Full donor chimerism and stable mixed chimerism with a high level of donor cells were compatible with disease free survival. On the contrary, progressive decrease of donor chimerism value was always followed by hematological relapse or graft rejection. CONCLUSIONS: Sequencial and quantitative detection of donor chimerism may be of great value to study the kinetics of engraftment of NST, to evaluate the status of engraftment, to predict the outcome and prognosis of patients posttransplant and to guide implementation of therapy at an early stage.

[The correlation of cytomegalovirus gB genotype with viral DNA load and treatment time in patients with CMV infection after hematopoietic stem cell transplantation].

OBJECTIVE: To explore the effect of CMV gB genotypes on viral load and treatment time in patients with CMV infection after hematopoietic stem cell transplantation (HSCT). METHODS: Viral load was detected by real-time (RT) quantitative polymerase chain reaction (PCR) (Q-PCR), CMV gB genotypes by PCR restriction fragment length polymorphism (RFLP) (PCR-RFLP) in 115 patients with CMV infection (CMV-DNA positive) after HSCT during July 2004 and May 2010. RESULTS: (1) The distribution of CMV gB genotypes in HSCT recipients were as following: gB1, 42/115 (36.52%); gB2, 3/115 (2.61%); gB3, 43/115 (37.39%); gB4, 2/115 (1.74%). 20 patients (17.39%) had a combination of 2 different CMV genotypes and 5 patients (4.35%) had a CMV variant that lacked an RsaI digestion site, herein named gB5. (2) The median viral load were 2.7×10(3)(1.81×10(3) ∼ 6.03×10(4)) in gB1, 4.0×10(3) (1.32×10(3) ∼ 6.39×10(4)) in gB3 and 1.2×10(4)(2.28×10(3) ∼ 6.50×10(5)) in mixed gB. There was no statistical difference in viral load between gB1 and gB3 (P > 0.050). There was significantly statistical difference in viral load between single-gB (gB1 or gB3) and mixed-gB (P < 0.05). (3) The median treatment time was 17 days in mixed-gB and 14 days in single-gB. There was significantly statistical difference between two groups (P < 0.05). Conclusion gB genotype may have an impact on CMV DNA load and treatment time in HSCT recipients with CMV infection.

[Influence of HLA-E polymorphism on cytomegalovirus infection after HLA-matched hematopoietic stem cell transplantation].

This study was aimed to explore the potential association of HLA-E polymorphism with the incidence of cytomegalovirus (CMV) infection after HLA-matched hematopoietic stem cell transplantation, 119 HLA-genoidentical sibling pairs for HLA-E polymorphism were analyzed, HLA-E DNA was amplified by polymerase chain reaction (PCR), and the amplified DNA products was also sequenced directly after purification to confirm the genotype. The results showed that the homozygous HLA-E*0101/0101 accounted for 20.17%, the homozygous HLA-E*0103/0103 accounted for 27.73%; heterozygous HLA-E*0101/0103 accounted for 52.10%; in homozygous HLA-E*0101/0101 group, 15 cases were infected with CMV and the CMV infection rate was 62.50%; in homozygous HLA-E*0103/0103 group, 16 cases were infected with CMV and the CMV infection rate was 48.48%; in heterozygous HLA-E*0101/0103 group 20 cases were infected with CMV and the CMV infection rate was 32.25%. As compared with the homozygous HLA-E*0101/0101 group, the CMV infection rate in HLA-E*0103 group displays statistical significance (P = 0.0295). The CMV infection rate occurred higher and its significance is statistical (P = 0.0074). It is concluded that the HLA-E gene polymorphism is associated with CMV infection after HLA-genoidentical bone marrow transplantation.

[Ex vivo inducing cultured Epstein-Barr virus specific cytotoxic T lymphocytes and evaluation of their killing effect].

This study was aimed to explore the method for induction and expansion of EB virus specific cytotoxic T lymphocytes (EBV-CTL) in vitro, and to detect their killing effect. Peripheral blood mononuclear cells (PBMNC) were collected from 6 EBV seropositive healthy donors, and EBV-transformed B lymphoblastoid cells (BLCL)were used as the antigen-presenting cells and antigen stimulant which was irradiated by 40 Gy (60)Co irradiator. The autologous PBMNC and irradiated BLCL were cultured to induce and expand the EBV-CTL, and the immunophenotype was identified by the flow cytometry. The killing effect of the EBV-CTL against the autologous BLCL (autoBLCL), the autologous PHA cultured B lymphoblastoid cells( PHA-BLCL), the allogeneic BLCL (alloBLCL) and the K562 cells were measured with LDH release assay under different effector-to-target ratio. The results showed that the 6 cell lines of EBV-CTL were induced and expanded from the EBV seropositive healthy donors, the overall increase in cell numbers varied from 18.6 to 55.0 times. After 10 stimulations, the specific killing efficiency of the EBV-CTL for the autoBLCL were 59.4%, 43.2% and 29.0% under the effector-to-target ratio of 20: 1, 10: 1 and 5: 1. The nonspecific killing efficiency for the PHA-blast, alloBLCL and K562 cells were 7.1%, 9.4% and 10.3% (P < 0.05) under the 20: 1 ratio; 6.6%, 8.3% and 8.1% (P < 0.05) under 10: 1; 5.4%, 7.3% and 6.3% (P < 0.05) under 5: 1, respectively. It is concluded that the EBV-CTL can be successfully induced and expanded ex vivo for specific killing of HLA matched BLCL and may become a potential treatment for EBV related post-transplant lymphoproliferative disorders.

[Quantitative monitoring of multi-donor chimerism after multi-donor allogeneic hematopoietic stem cell transplantation].

This study was aimed to establish a model for detecting the donor chimerism rate following the multi-donor hematopoietic stem cell transplantations, and simplify its calculation method. Patients with hematologic disease receiving allogeneic hematopoietic stem cell transplantation including single-donor and multi-donor were selected in this study and the donor cell chimerism rates were detected, using STR-PCR combined with capillary electrophoresis. The results indicated that the peaks of the sister alleles coming from the same individual were confirmed to have the approximate areas and can be replaced each other in the situation of mixed chimerism. In the calculation model, the value between reference chimerism and approximate chimerism have no significant difference using the hypothetical peak areas, and the result was confirmed to be accepted basing on typical measurement error between sister alleles (5% - 20%). It is concluded that the areas of share peaks can be replaced by non-share peaks and this conclusion can be used to calculate the double-donor CHM (DD-CHM)(%). Compared to the D alleles, R alleles show more strategic importance because it can lead to more accurate result and allowed simplifying the arithmetic calculations for DD-CHM(%).

[Culture and pluripotentiality of murine compact bone-derived mesenchymal stem cells].

This study was purposed to culture murine compact bone-derived mesenchymal stem cell (MSC) and analyze the immunological and trilineage differentiation potential. Tibia and femur were extracted. Bone marrow cells were flushed out and compact bone fragments were digested with collagenase. The digested cells were cultured in 6-well plates. The immunophenotype, immunosuppressive function and trilineage differentiation potential were analysed by flow cytometry, mixed lympocyte reaction and Oil red O, von Kossa and alcian blue straining, respectively. The results indicated that the pure compact bone MSC could be isolated with in 3 weeks. The resulting MSC had trilineage differentiation potential and immunosuppressive effect on mixed lymphocyte reaction. The count per minute (CPM) value in control group of BALB/c T cells cocultured with irradiated C57BL/6 T cells was (2.56 ± 0.31) × 10(4), while CPM values of mixed lymphocyte cocultured with C57BL/6 compact bone MSC at ratios of 100:1 and 10:1 were (0.47 ± 0.12) × 10(4) and (0.28 ± 0.09) × 10(4). The CPM value of control group was higher than those of MSC cocultured group (P < 0.001). Compact bone-MSC had an immunosuppressive effect on mixed lymphocyte reaction in a dose dependent manner. It is concluded that murine compact bone has rich MSC and the primary MSC is contaminated with less hematopoietic cells. Murine compact bone-MSC have immunosuppressive effect on mixed lymphocyte reaction and trilineage differentiation potential. Compact bone-MSC have promising experimental study value.

[Effects of simvastatin on proliferation and apoptosis of acute monocytic leukemia cell line SHI-1].

The purpose of this study was to investigate the effect of simvastatin (SIM) on proliferation and apoptosis of acute monocytic leukemia cell line SHI-1 and its mechanism. Experiments were divided into control and test groups (5 µmol/L, 10 µmol/L, 20 µmol/L SIM groups). The growth inhibitory rate of SHI-1 cells was detected using methyl thiazolyl tetrazolium (MTT) method. The cell cycle distribution and apoptotic rate were measured by using flow cytometry. The expression of BCL-2, caspase-3 mRNA were determined by reverse transcription polymerase chain reaction (RT-PCR). The expression of BCL-2, caspase-3 protein levels were analyzed by Western blot. The results demonstrated that SIM inhibited the growth of SHI-1 cells in time- and does-dependent manners. Cell cycle analysis showed that SHI-1 cells significantly arrested in S phase (p < 0.05) after treating with SIM for 48 hours, as compared with control group. 5 µmol/L SIM in test group significantly blocked cell cycle progression, but can not induce apoptosis. The expressions of BCL-2 mRNA and protein were down-regulated and caspase-3 mRNA and protein were up-regulated along with the increase of SIM concentration (p < 0.05). It is concluded that SIM is able to inhibit proliferation and induce apoptosis of SHI-1 cells, the mechanism may be associated with downregulating the expression of apoptosis-related gene BCL-2, upregulating the expression of caspase-3.

[Quantitative analysis for JAK2 mutation in 98 patients with essential thrombocythemia and its clinical significance].

The objective of this study was to identify the frequency and types of JAK2V617F mutation in chinese patients with essential thrombocythemia (ET), to quantitatively detect the level of mutation transcripts and to investigate its clinical significance. The frequency and types of JAK2V617F mutation were detected by amplification-refractory mutation sequencing polymerase chain reaction (ARMS-PCR), the transcript level of JAK2V617F mutation was determined by using capillary electrophoresis. The results indicated that the JAK2V617F mutation was detected in 59 out of 98 patient with ET, 18 of whom were homozygous mutation. The mean age of patients with homozygous and heterozygous mutation was higher than that of patients with wild type mutation (p < 0.05). The quantitative assay using capillary electrophoresis showed that the transcript level of JAK2V617F mutation in patients with homozygous mutation was (89.9 +/- 6.7)%, which was higher than that in patients with heterozygous mutation (57.1 +/- 6.7)% (p < 0.05); the transcript level of JAK2V617F mutation in patients with age < 60 years was (62.3 +/- 16.5)%, which was lower than that in patients with age > 60 years (72.4% +/- 15.8)% (p < 0.05). The rate of thrombotic complications in patients with JAK2V617F-positive was higher than that in patients with JAK2V617F-negative in which the rate of thrombotic complication in patients with homozygous mutation was higher than that in patients with heterozygous mutation (p < 0.05). Compared with patients without thrombotic events, there were higher level of transcripts of JAK2V617F mutation in patients with thrombotic events. It is concluded that the JAK2V617F positive and negative patients with ET display the different clinical features, therefore, the analysis of mutation types and detection of transcript levels not only helps to identify the disease status and progression, but also guides the treatment of ET patients.

[A quantitative assay for JAK2 mutation in 135 patients with chronic myeloproliferative neoplasms].

OBJECTIVE: To investigate the frequency and mutational status of JAK2 mutation in Chinese patients with chronic myeloproliferative neoplasms (MPN) and study the relative quantitation and clinical implications of mutated JAK2 transcript. METHODS: JAK2 mutation and the mutational status were screened with amplification-refractory mutation sequencing polymerase chain reaction (ARMS-PCR), the relative quantity of mutated JAK2 mRNA by using capillary electrophoresis. RESULTS: JAK2V617F mutation was detected in 95 of 135 MPN patients, including 37 (97.4%) of 38 polycythemia vera (PV), 56 (59.6%) of 94 essential thrombocythemia (ET) and 2 of 3 idiopathic myelofibrosis (IMF) patients; the difference between the mutations in PV and ET was significant (P<0.05). Of 95 JAK2V617F patients examined, 18/38 PV patients (47.3%) and 17/94 (18.1%) ET patients and 1 IMF patient were homozygotes, and ET patients showed lower prevalence of homozygote (P<0.05). In 95 MPN patients, the mutated mRNA ratio was higher in homozygote than in heterozygote patients. PV heterozygote patients showed higher levels of mutated JAK2 mRNA than ET heterozygote patients (P<0.05). The levels of JAK2V617F mRNA in patients over 60 years of age were significantly higher than that in those less than 60 years of age (P<0.001). Higher leukocyte counts were observed in PV and ET patients with higher levels of mutated JAK2 mRNA (P<0.05). The presence of JAK2V617F was found to be significantly associated with higher hemoglobin level in ET patients. Cytogenetic analysis was performed in 101 of the 135 patients, the association between abnormal karyotype and JAK2V617F was not found. CONCLUSION: The ARMS-PCR technique can be used to detect the frequency and mutational status of JAK2V617F mutation, and along with capillary electrophoresis, the estimation of minimal residual disease becomes possible.

[5-azacytidine treatment induces tumor suppressor gene XAF1 expression and inhibits proliferation in myeloma cells].

OBJECTIVE: To investigate the effect of 5-azacytidine on XAF1 expression in myeloma cell lines RPMI8226 and XG-7 and the in vitro anti-myeloma activity of 5-azacytidine. METHODS: XAF1 mRNA and protein expression was detected by semi-quantitative reverse transcriptase PCR and Western blot, respectively. Methylation specific PCR (MSP) was used to detect methylation status of XAF1 promoter CpG islands. RPMI8226 and XG-7 cells were treated with 0-5 micromol/L of 5-azacytidine and Cell Counting Kit-8 colorimetric assay was used to evaluate the growth inhibitory effect. Cell apoptosis was determined with Annexin V-PE/7-AAD staining by flow cytometry. RESULTS: Untreated RPMI8226 cells expressed XAF1 mRNA isoforms 1 and 2, and untreated XG-7 cells had no XAF1 expression. Hypermethylation of XAF1 promoter CpG islands was detected in both the cell lines. After treated with 2.5 micromol/L 5-azacytidine for 72 h, both the cell lines expressed full-length XAF1 transcript and protein. 5-azacytidine treatment led to XAF1 promoter CpG islands hypomethylation and showed anti-myeloma activity in a time- and concentration-dependent manner with IC50 of 2.4 micromol/L and 2.6 micromol/L at 48 h for RPMI8226 and XG-7 cell lines, respectively. CONCLUSIONS: Lack of XAF1 expression and abnormal expression of XAF1 in myeloma cell lines are associated with XAF1 gene promoter CpG islands hypermethylation. 5-azacytidine treatment can induce XAF1 mRNA and protein expression and exerts anti-myeloma activity via apoptosis at clinically achievable concentrations.