Role of Flow Cytometry in the Diagnosis of Chronic Myeloid Leukemia / 中国实验血液学杂志

OBJECTIVE@#To analyze the immunological phenotype of chronic myeloid leukemia (CML), and explore its characteristics and significance.@*METHODS@#The immunophenotypes of 40 CML children and 40 controls were analyzed by multicolor flow cytometry. CD45/SSC, as the basic gate, was used to delineate neutrophils. Then, the distribution of cluster differentiation (CD) molecules on the surface of granulocytes was analyzed in three ranges (≥1%, ≥5%, and ≥20%), and the expression rates of CD molecules (≥1% included in the statistical analysis) and the mean fluorescence intensity (MFI) were compared between the two groups.@*RESULTS@#The proportion of granulocytes in the CML group was (82.1±6.4)%, which was significantly higher than (57.8±11.8)% in the control group (P <0.001). The expression rates of CD15/CD11b/CD33/CD13 in CML and control groups were high, and both distributed in the range of ≥20%. The differentiation trajectory of CD33/CD13 was normal and there were no significant differences in the expression rate and MFI between the two groups. However, both the expression rate of CD11b and CD15 MFI in the CML group were significantly lower than those in the control group (P <0.001). There were no significant differences in the expression rate and MFI of CD10 between the two groups, and the expression levels of CD10 between the two groups were consistent in different distributions. In the CML group, there was a large number of cases with abnormal high expression of CD56, 52.5% of the cases had a CD56 expression rate of ≥5%, and 42.5% had a CD56 expression rate of ≥20%, while the control group did not express CD56 (<1%). The expression distribution of CD117 was different between the two groups. In the range of expression rate ≥5%, there were 35.0% cases in the CML group, while only 2.5% in the control group. The expression rate of CD117 in the CML group was higher than that in the control group (P <0.001), though there was no significant difference in MFI.@*CONCLUSION@#The immunophenotyping of CML is characterized by increased proportion of mature neutrophils, decreased CD15 MFI, decreased proportion of CD11b and abnormal high expression of CD56 and CD117. Flow cytometric analysis of immunophenotype can effectively distinguish normal granulocytes from chronic granulocytes, and help in the diagnosis of CML.

Effect of Human Bone Marrow Mesenchymal Stem Cells with Ectopic High OCT4 Expression on T Lymphocyte Function / 中国实验血液学杂志

OBJECTIVE@#To explore the effect of human bone marrow mesenchymal stem cells (MSCs) with ectopic high OCT4 expression on T-cell proliferation, activation and secretion in vitro.@*METHODS@#Peripheral blood mononuclear cells were isolated from healthy children. Anti-CD3 and anti-CD28 monoclonal antibodies were used to activate T lymphocytes, which were stimulated by interleukin (IL)-2 for one week in vitro. Then MSCs with ectopic high OCT4 expression (MSC-OCT4) were co-cultured with activated T lymphocytes. After one week of co-culture, the supernatant was collected and the levels of Th1/Th2 cytokines [IL-2, IL-4, IL-6, IL-10, tumor necrosis factor (TNF)-α and interferon (IFN)-γ] were determined by flow cytometry. The lymphocytes after one week of co-culture were collected and counted by Countstar software. After the proportions of activated/inactivated T cell subsets were determined by flow cytometry, the absolute lymphocyte counts were calculated and expressed as mean ± standard deviation.@*RESULTS@#Compared with control T cell alone culture group, the proliferation of CD3+ T cells, CD3+CD4+ T cells, and CD3+CD8+ T cells were significantly inhibited in MSC group and MSC-OCT4 group. Compared with MSC, MSC-OCT4 could inhibit CD3+CD8+ T cell proliferation better (P =0.049), and mainly inhibited early T cell activation. Compared with control T cell alone culture group, the levels of IL-2 and INF-γ were significantly down-regulated both in MSC group and MSC-OCT4 group.After co-culture with T cells for one week, the level of IL-6 significantly increased in MSC group and MSC-OCT4 group compared with that before co-culture. Compared with control MSC group, MSC-OCT4 group had higher viable cell numbers after 1 week of co-culture (P =0.019), and could resist the inhibition of proliferation by higher concentration of mitomycin C.@*CONCLUSION@#Both MSC and MSC-OCT4 can inhibit the proliferation and activation of IL-2-stimulated T cells in vitro. After overexpression of OCT4, MSC has better proliferation ability in vitro and can inhibit the proliferation of CD3+CD8+ T cells more effectively, which may have a better and more lasting immunosuppressive ability to regulate the balance of Th1/Th2.

Effect of OCT4 Gene Expression Upregulation on the Expression of iPSC-related Transcription Factors in Human Bone Marrow Derived Mesenchymal Stem Cells / 中国实验血液学杂志

OBJECTIVE@#To explore the effect of OCT4 over-expression on the expression of induced pluripotent stem cell (iPSC)-related transcription factors (cMYC，KLF4，LIN28，NANOG and SOX2) in human bone marrow derived mesenchymal stem cells (hBMMSCs), so as to provide fundamental basis for exploring the pathogenesis of hematological diseases (leukemia, aplastic anemia, etc.) from the perspective of hemopoietic microenvironment in the future.@*METHODS@#Recombinant plasmid pcDNA3.1-OCT4 was constructed and transferred into the optimal generation P3-4 hBMMSCs by liposome transfection. The cells with stable and high expression of OCT4（hBMMSCs-OCT4）were screened by G418 resistance screening (limited dilution) and subcloning, the expression of OCT4 mRNA and OCT4 protein was verified by RT-PCR and FCM, respectively. The expression of iPSC-related transcription factors (cMYC, KLF4, LIN28, NANOG and SOX2) were also determined by FCM and RT-PCR, so as to evaluate the effect of ectopic high expression of OCT4 on the expression of iPSC related transcription factors in hBMMSCs.@*RESULTS@#Recombinant plasmid pcDNA3.1-OCT4 was successfully constructed and cells with stable and high expression of OCT4 were successfully screened from hBMMSCs by limited dilution and subcloning. The result of flow cytometry showed that the mean expression level of OCT4 protein increased from (3.03±1.49)% to (95.46±1.40)% compared with the untransfected parental MSCs, which was also confirmed by RT-PCR analysis. At the same time, the expression levels of OCT4 protein and mRNA were compared between transient transfection (day 4) and stable expression cells (day 96), respectively, it was showed that the OCT4 protein level increased from (36.36±0.28)% at day 4 to (96.25±1.38)% at day 96, and the OCT4 mRNA level increased from 2.75-folds to 6.23-folds, respectively. Compared with the untransfected parental MSCs, the average expression levels of stemness transcription factors increased from (1.12±0.47)% (cMYC), (0.84±0.30)% (KLF4), (2.14±0.79)% (LIN28), (0.63±0.37)% (NANOG) and (14.34±2.44)% (SOX2) to (80.65±4.75)%, (73.03±4.70)%, (68.08±3.05)%, (39.39±1.85)%and (91.45±4.56)% in hBMMSCs-OCT4, respectively, which were consistent with results of RT-PCR analysis. Moreover, the expression levels of NANOG and SOX2 positively correlated with the mean expression of OCT4 (OCT4 vs NANOG: r=0.7802，OCT4 vs SOX2: r=0.4981；NANOG vs SOX2: r=0.7426).@*CONCLUSION@#Cells with stable and high expression of OCT4 have been successfully established from hBMMSCs. Ectopic high expression of transcription factor OCT4 in hBMMSCs can up-regulate the expression of other iPSC-related transcription factors such as cMYC, KLF4, LIN28, NANOG and SOX2.

A genetic analysis of children with Epstein-Barr virus-positive hemophagocytic lymphohistiocytosis and its association with T-helper type 1/T-helper type 2 cytokines / 中国当代儿科杂志

OBJECTIVE@#To study the effect of genetic variation on the prognosis of children with Epstein-Barr virus (EBV)-positive hemophagocytic lymphohistiocytosis (HLH) and its association with cytokines.@*METHODS@#A total of 81 EBV-positive HLH children who received the sequencing of related genes were enrolled. According to the results of gene detection, they were divided into a non-mutation group and a mutation group. According to the pattern of gene mutation, the mutation group was further divided into three subgroups: single heterozygous mutation (SHM), double heterozygous mutation (DHM), and homozygous or compound heterozygous mutation (H-CHM). The serum levels of cytokines were measured and their association with HLH gene mutations was analyzed.@*RESULTS@#UNC13D gene mutation had the highest frequency (13/46, 28%). The STXBP2 c.575G>A(p.R192H) and UNC13D c.604C>A(p.L202M) mutations (likely pathogenic) were reported for the first time. The mutation group had a significantly higher level of tumor necrosis factor alpha (TNF-α) than the non-mutation group, while it had a significantly lower level of interferon gamma (IFN-γ) than the non-mutation group (P<0.05). The IL-4 level of the DHM subgroup was higher than that of the non-mutation group, while the IL-4 level of the H-CHM subgroup was lower than that of the DHM group (P<0.0083). The H-CHM subgroup had a significantly lower 1-year overall survival rate than the non-mutation group, the SHM subgroup, and the DHM subgroup (39%±15% vs 85%±6%/86%±7%/91%±9%, P=0.001).@*CONCLUSIONS@#There is a significant reduction in IFN-γ level in the mutation group. Children with homozygous or compound heterozygous mutation tend to have poorer prognosis, while other mutations do not have a significant impact on prognosis.

Progress in clinical studies of chimeric antigen receptor engineered T cells for treatment of childhood cancer / 中国当代儿科杂志

Nowadays, the 5-year survival rate of childhood cancer patients can be more than 80%, but some patients with relapse and refractory cancers have shown no good response to traditional strategies. Chimeric antigen receptor engineered T (CAR-T) cell therapy is promising for these patients. CAR-T cells recognize the tumor-associated antigens in a non-major histocompatibility complex-restricted manner, so their anti-tumor ability is enhanced. There are four generations of CAR-T cells now. The complete remission rate of pediatric patients with relapse and refractory acute lymphoblastic leukemia can be as high as 90% when treated with CD19-targeting CAR-T cells. Furthermore, CAR-T cell therapy can also be used to bridge to transplantation and donor CAR-T cell infusion can be a strategy to prevent relapse after hematopoietic stem cell transplantation. As to solid tumors, only patients with neuroblastoma present good response to the GD2-targeting CAR-T cell therapy. The toxic or side effects of CAR-T cell therapy include cytokine release syndrome, off-tumor effect, tumor lysis syndrome, and insertion mutation. Although the CD19-targeting CAR-T cell therapy for childhood cancer can result in a high remission rate, the relapse rate is high, including CD19and CD19relapse. The mechanisms for relapse merit further investigatio.

Serum cytokine levels in children with newly diagnosed active systemic juvenile idiopathic arthritis / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To study the changes in serum cytokines levels in children with newly diagnosed active systemic juvenile idiopathic arthritis (SJIA) and to explore the role of cytokines in the development and progression of SJIA.</p><p><b>METHODS</b>Seventy-four pediatric patients with active SJIA between January 2010 and December 2013 were included in the study. Serum levels of interleukin-2 (IL-2), interleukin-4 (IL-4), interleukin-6 (IL-6), interleukine-10 (IL-10), tumor necrosis factor (TNF), and interferon gamma (IFN-γ) were measured by flow cytometry in these patients. The levels of cytokines were also determined in 202 healthy children as the control group. Routine laboratory parameters including white blood cell (WBC) count, percentage of neutrophils, hemoglobin level, platelet count, hypersensitive C-reactive protein (hs-CRP), and erythrocyte sedimentation rate (ESR) were monitored in the patient group.</p><p><b>RESULTS</b>The WBC count, percentage of neutrophils, hs-CRP, and ESR in 74 cases of SJIA were significantly above the normal range, their platelet counts were within the normal range, whereas hemoglobin levels were below the normal range. Compared with the control group, the patient group showed a significantly increased level of IL-6 (P<0.01) and significantly reduced levels of IL-4, IL-10, and TNF (P<0.01). However, there were no significant changes in serum levels of IL-2 and IFN-γ in the patient group (P>0.05). In SJIA children, IL-6 level, which was significantly elevated, was negatively correlated with hemoglobin level, which was significantly reduced (r=-0.244, P<0.05).</p><p><b>CONCLUSIONS</b>Serum level of IL-6 is significantly increased in children with SJIA, and it has a negative correlation with anemia.</p>

Clinical and laboratory characteristics of chronic active Epstein-Barr virus infection in children / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To study the clinical and laboratory characteristics of chronic active Epstein-Barr virus (EBV) infection (CAEBV) in children and to provide a basis for the diagnosis and treatment of CAEBV.</p><p><b>METHODS</b>The clinical data of 13 children with CAEBV, as well as 15 cases of acute EBV infection (AEBV) as controls, were analyzed, including clinical manifestations, EBV antibodies, EBV DNA, and peripheral blood lymphocyte subsets.</p><p><b>RESULTS</b>Both groups of patients had infectious mononucleosis-like symptoms such as fever, hepatomegaly, splenomegaly, and lymphadenectasis, but CAEBV patients had a longer course of disease and continuous and recurrent symptoms. Compared with the AEBV group, the CAEBV group had a significantly higher EBV DNA load in peripheral blood (P<0.05), a significantly higher VCA-IgG titer (P<0.05), and significantly lower numbers of white blood cells, lymphocytes, B cells, total T cells, CD4+ T cells, and CD8+ T cells in peripheral blood (P<0.05). Among 13 CAEBV patients followed up, 8 cases died, 2 cases showed an improvement, 2 cases had a recurrence, and 1 case was lost to follow-up after being transferred to another hospital. All the AEBV patients were cured and had no recurrence during the one-year follow-up.</p><p><b>CONCLUSIONS</b>The clinical manifestations of CAEBV vary in children. It is difficult to distinguish CAEBV from AEBV early. More attention should be paid to CAEBV because of its severe complications, poor prognosis, and high mortality. Measurement of EBV DNA load, VCA-IgG titer, and lymphocyte subsets in peripheral blood may be helpful in the diagnosis and differential diagnosis of CAEBV.</p>

Advances in immunotherapy of hematological malignancies by using chimeric antigen receptor-modified lymphocytes / 中国实验血液学杂志

Chimeric antigen receptors (CAR) are fusion proteins between single-chain variable fragments (scFv) from monoclonal antibodies and signaling domains of T-cells, which allow T-cells recognize specific cell-surface targets in an MHC-unrestricted fashion. The structure of CAR has changed over time, from first generation CAR (scFv + signaling moiety) to 2 and 3 generation CAR (combined with one or multiple costimulatory endodomains, such as CD28, 4-1BB and OX40), which enhance persistence, expansion and cytotoxicity of CAR. Many clinical trials treating hematological malignancies using the CAR-modified T-cells targeting CD19 and CD20 are under evaluation or even finished. These clinical trials indicated that CAR-based immunotherapy prolonged the survival of patients with relapsed/refractory B-cell malignancies. Furthermore, CAR have being studied to translate to other fields like adoptive therapy after hematopoietic stem cell transplantation. As to the treatment toxicity, CAR modified T-cell infusion is tolerant and safe in most patients. However, insertional mutagenesis, off-target effect and inflammatory response are safety issues surrounding CAR-modified T-cell therapy. In this review, the use of CAR technique in treatment of hematologic malignancies and evaluation of CAR safety are summarized.

Establishment of a transgenic cell line with stable expression of human CD14 / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To establish a transgenic cell line with stable expression of CD14.</p><p><b>METHODS</b>Total RNA extracted from peripheral blood mononuclear cells was treated with RNAase-free DNAase, the human CD14 gene was cloned and sequenced through the RT-PCR, T-A clone techniques and ABI PRISM377 machine. Eukaryotic expression vector pcDNA3.1(+)/CD14 was constructed by cleaving with double restriction endonucleases EcoR I/Xba I and ligating with T4 ligase. The human cervical cancer cell line Hela was transfected with the positive recombinant plasmid pcDNA3.1(+)/CD14 using superfect transfection reagent. Positive clones were selected by G418 at a concentration of 0.5 μg/μl and the expression of human CD14 on the transfected Hela cells was confirmed by quantitative PCR and immunofluorescent assay.</p><p><b>RESULTS</b>There was significantly difference om expression of CD14 mRNA between the blank pcDNA3.1(+) transfected cells and pcDNA3.1(+)/CD14 transfected cells (P<0.01). The fluorescence was significantly stronger on the stable cell line Hela-CD14 than that on the transiently transfected Hela cells,and no visible fluorescence was observed in blank vector transfected cells.</p><p><b>CONCLUSION</b>The transfectant cell line Hela-CD14 with stable expression of human CD14 has been successfully established, which can be used to study human CD14 molecular and CD14-associated monocyte/macrophage cell diseases.</p>

Drug resistance of extended-spectrum-β-lactamases-producing bacteria in children with hematological malignancy after chemotherapy / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To study the prevalence and drug resistance of extended-spectrum-β-lactamases (ESBLs)-producing bacteria in blood culture isolated from children with hematological malignancy after chemotherapy.</p><p><b>METHODS</b>Blood samples taken from 3264 children with hematological malignancy and severe infection following chemotherapy between 2002 and 2008 were cultured using the Bact/ALTER 3D blood culture system. VITEK 60 automicroscan was used to identify viral species and to conduct drug resistance tests. The results were indentified according to National Committee for Clinical Laboratory Standard guidelines.</p><p><b>RESULTS</b>Fifty-eight strains of Escherichia coli and fifty-one strains of Klebsiella pneumoniae were isolated. Thirty-eight strains of Escherichia coli and nineteen strains of Klebsiella pneumoniae were ESBLs-producing and these ESBLs-producing strains were less susceptible than those that were non-ESBLs-producing to most antibiotics. Both ESBL- and non-ESBL-producing strains were susceptible to imipenem, piperacillin/tazobactam and amikacin.</p><p><b>CONCLUSIONS</b>The prevalence of ESBLs-producing bacteria is high in childrn with hematological malignancy and infection following chemotherapy. ESBLs-producing bacteria are resistant to common antibiotics, suggesting that antibiotic treatment based on the result of antimicrobial susceptibility test is necessary in these children.</p>

Effectiveness of immunosuppressive therapy for childhood aplastic anemia and its predictive factors / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To evaluate the effectiveness of immunosuppressive therapy (IST) for childhood aplastic anemia (AA) and its predictive factors.</p><p><b>METHODS</b>The medical data of 110 children with AA who received IST between February 2003 and November 2009 were retrospectively studied. Of these patients, 83 were diagnosed as severe AA (SAA) and 27 were non-SAA. The former group was treated with antithymocyte globulin (ATG) + ciclosporin (CSA) +prednisone + androgens and the latter with CSA + prednisone + androgens.</p><p><b>RESULTS</b>Total response rates in the SAA and non-SAA groups were 69.9% and 70.4%, respectively. Univariate analysis showed that disease duration, CD34+ cell level in bone marrow (BM) and the expression of CD4+CD25+ regulatory T cell in BM were related to the severity of disease but not correlated with treatment response. Age, disease duration and proportions of CD3+ and CD8+ T cells in BM were predictive factors for response to IST. Multivariate analysis revealed that patients aged more than 10 years and patients with a CD8+ cell proportion in BM of over 25% had hazard ratios of 3.36 and 3.59 for treatment failure respectively.</p><p><b>CONCLUSIONS</b>IST is effective in the treatment of childhood AA. Age, disease duration and the proportion of CD8+ T cell in BM are predictive factors for response to IST.</p>

Diagnostic significance of Th1/Th2 cytokine pattern in childhood hemophagocytic lymphohistiocytosis / 中华儿科杂志

<p><b>OBJECTIVE</b>To illustrate the diagnostic value of Th1/Th2 cytokine pattern in childhood hemophagocytic lymphohistiocytosis (HLH) and its diagnostic accuracy.</p><p><b>METHOD</b>The BD(TM) CBA Human Th1/Th2 Cytokine Kit II was used to measure the serum Th1 and Th2 cytokines, including Interferon-gamma (IFN-γ), tumor necrosis factor (TNF), interleukin (IL)-10, IL-6, IL-4 and IL-2 in 50 patients with de novo HLH admitted to our hospital from Oct. 2005 to Aug. 2009. The above cytokine levels were also determined in 250 healthy volunteers and 235 patients with sepsis as controls.</p><p><b>RESULT</b>The primary features of these patients were prolonged high-grade fever (50/50), hepatomegaly (44/50), splenomegaly (38/50), hemocytopenia (47/50), hyperferritinemia (49/50), coagulopathy (44/50), hemophagocytosis in bone marrow (42/50), liver dysfunction (42/50) and hypertriglyceridemia (42/50). The IFN-γ, TNF, IL-10, IL-6, IL-4 and IL-2 levels for healthy children were (4.6 ± 1.8) ng/L, (4.0 ± 1.2) ng/L, (6.5 ± 1.3) ng/L, (6.0 ± 1.5) ng/L, (2.9 ± 0.8) ng/L and (2.6 ± 0.7) ng/L, while the median levels of them in acute phase of HLH children were 1138.5 (49.2 - 5000.0) ng/L, 3.4 (1.0 - 25.1) ng/L, 740.5 (26.5 - 5000.0) ng/L, 66.1 (3.9 - 4472.6) ng/L, 3.9 (1.0-32.8) ng/L and 4.0 (1.0 - 51.1) ng/L, respectively. The cytokine levels decreased to 9.1 (1.9 - 180.1) ng/L, 2.9 (1.0 - 11.0) ng/L, 11.4 (2.9 - 184.2) ng/L, 6.5 (1.0 - 44.8) ng/L, 2.7 (1.0 - 6.5) ng/L and 4.1 (1.0 - 12.0) ng/L respectively after remission. The IFN-γ, IL-10 and IL-6 levels in acute phase were significantly higher than those after remission and those of the healthy control (P all < 0.001). IL-4, IL-2 and TNF slightly elevated or at normal range in acute phase of HLH. The patients with sepsis showed a different cytokine pattern, with an extremely high level of IL-6 (median: 251.3 ng/L, range: 8.4- > 5000.0 ng/L) and moderately elevated level of IL-10 (median: 46.5 ng/L, range: 3.1 - 5000.0 ng/L), whereas IFN-γ was only slightly elevated (median: 9.2 ng/L, range: 1.3 - 498.8 ng/L). When the criteria for HLH set as the following: IFN-γ > 100 ng/L, IL-10 > 60 ng/L and the concentration of IFN-γ higher than that of IL-6, the specificity reached as high as 98.7% and the sensitivity was 88.0% for the diagnosis of HLH among patients with HLH and sepsis. Meanwhile, the positive predictive value (PPV) and negative predictive value (NPV) could reach 93.6% and 97.5%, respectively.</p><p><b>CONCLUSION</b>The significant increase of IFN-γ and IL-10 with slightly increased level of IL-6 is a sensitive and specific cytokine pattern for childhood HLH, which is helpful for its diagnosis and differential diagnosis.</p>

Determination of leukemia stem cells in childhood acute myeloid leukemia and its clinical significance / 中国实验血液学杂志

The aim of this study was to detect the presence of human AML leukemia stem cells (LSC) in childhood patients with acute leukemia (AL) and analyze the correlation between LSC concentrations and minimal residual disease (MRD) levels in AML cases after remission. The multi-parameter flow cytometry (FCM) and a panel of monoclonal antibody combination were used to detect the AML LSC or AML LSC immunophenotype-identical cell (AML LSC-IPIC) concentrations in childhood AML or ALL leukemia both at new diagnosis and at remission and correlated AML LSC to the MRD levels at different time points after remission. The results indicated that the AML LSC or AML LSC-IPIC concentrations [in average 166 (range 14 - 1459)/100 000 mononuclear cells (MNCs)] in AML at initial diagnosis were significantly higher than those in ALL [7 (range 0 - 560)/100 000 MNCs, p < 0.017] and control [0 (range 0 - 6)/100 000 MNCs, p < 0.017], respectively. The AML LSC concentrations in AML at non-CR were in average 36 (range 5 - 224)/100 000 MNCs. No statistical difference (p > 0.05) was found between the AML LSC or AML LSC-IPIC concentrations in AML (in average 6 (range 0 - 41)/100, 000 MNCs) and ALL [10 (range 0 - 105)/100, 000 MNCs] after CR. The significantly negative correlation was noticed between AML LSC concentrations and MRD levels. It is concluded that the AML LSCs exist in newly diagnosed AML, which are significantly reduced when complete remission has achieved, but the low levels of these populations still remain. The phenotypically similar (CD34(+)CD38⁻CD123(+)) AML LSC populations have also been found in the bone marrow from ALL patients, but their concentrations are not significantly different when CR has achieved. The significantly negative correlation between AML LSC concentrations and MRD levels is observed in AML patients after remission.

Monitoring of minimal residual disease in children with acute lymphoblastic leukemia and its prognostic significance / 中华儿科杂志

<p><b>OBJECTIVE</b>Monitoring of minimal residual disease (MRD) is proven to be increasingly valuable for predicting relapse and outcome of childhood acute lymphoblastic leukemia (ALL) and is used to identify patients' risk groups in several current clinical trials. However, the limitation is that most studies focused on the cut-off value at 10(-4) and the time point after induction. The aim of this study was to investigate the predictive values of different MRD levels detected at different chemotherapy phases in childhood ALL.</p><p><b>METHODS</b>One hundred and two patients were enrolled in this study from January 2002 to December 2004 in our hospital. All the patients were treated with modified National Protocol of Childhood ALL in China 1997. MRD levels were detected on the 15th day, 29th day, at 3 months, 6 months and 12 months after initial chemotherapy. All samples were stained with a panel of four colour combinations of fluorochrome conjugated monoclonal antibodies according to the leukemia-associated immunophenotype (LAIP) defined at diagnosis and analyzed by multi-parametric flow cytometry. CD45CD19CD34CD10, CD45CD19CD34CD20 and CD45CD19CD10CD20 were the most common combinations in B lineage ALL, while CD45CD2CD3CD7 and CD45CD2CD3CD34 were the most frequently used immunophenotypes for T lineage ALL. The median follow-up time was 63.3 months ranged from 40.6 to 87.5 months.</p><p><b>RESULTS</b>Of the 102 patients, 64 were male and 38 were female, with a median age of 5.7 (0.2 - 14.8) years. Eighty-eight cases were diagnosed as B lineage ALL and the remaining 14 were T-ALL. The 5-year overall survival (OS) rate and event free survival (EFS) rate for this cohort were (86.9 +/- 3.4)% and (79.9 +/- 4.0)%, respectively. Twelve patients underwent relapse. Among the 102 patients, 14.3% had negative MRD (MRD < 10(-4)) on day 15, 43.9% on day 29, 39.1%, 39.7% and 45.6% had negative MRD at the third, sixth and twelfth month after chemotherapy. Patients who could achieve negative MRD within one year had superior outcome to the others [5-year EFS rates: (92.5 +/- 3.2)% vs. (58.3 +/- 8.6)%, P < 0.001]. The EFS for patients based on MRD levels measured at different stages of therapy were compared by Kaplan-Meier analyses. MRD was predictive of outcome at all 5 time points at a range of thresholds. The optimum threshold, selected for each time point on the basis of log rank analysis, progressively dropped from 10(-2) of day 15 [5-year EFS rates (79.8 +/- 10.3)% vs. (28.6 +/- 17.1)%, P < 0.001], to 10(-3) of day 29 [5-year EFS rates (88.3 +/- 4.9)% vs. (51.3 +/- 14.4)%, P < 0.003], to 10(-4) at 3 [5-year EFS rates (92.4 +/- 5.1)% vs. (65.5 +/- 7.5)%, P < 0.015], 6 [5-year EFS rates (96.3 +/- 3.6)% vs. (65.4 +/- 7.5)%, P < 0.003] and 12 [5-year EFS rates (100.0 +/- 0.0)% vs. (67.7 +/- 8.4)%, P < 0.002] months. And the hazard ratios for relapse and death at higher MRD level groups were 5.91 (95%CI: 1.9 - 18.9), 5.02 (95%CI: 1.5 - 16.5), 5.21 (95%CI: 1.2 - 22.9) and 11.10 (95%CI: 1.5 - 84.5) on day 15, day 29, at month 3 and month 6, respectively. And MRD >or= 10(-2) on day 15 was proven to be an independent predictor by multivariate Cox proportional-hazards regression model.</p><p><b>CONCLUSION</b>Dynamic MRD detection by multi-parametric flow cytometry is highly predictive of outcome for childhood ALL, and the cut-off values at different time points were different.</p>

Targeted killing of the Nalm-6 cells with 2E8-Genistein immunotoxin and its mechanism / 中华儿科杂志

<p><b>OBJECTIVE</b>Leukemia is the most common hematopoietic malignancies in children. Chemotherapy is currently the primary modality of treatment for this fatal disease. Although chemotherapy is very effective in terms of cell killing, severe side effects such as severe infections, intracranial hemorrhage etc. are frequently encountered due to its poor selective damage between normal and malignant cells or tissues. Thus, a new therapy with highly selective killing of malignant cells which leaves the normal cells unaffected is desperately desired. The aim of this study was to investigate the targeting efficacy in vitro with a new clone of anti-human CD19 antibody immunotoxin 2E8-Genistein on B lineage leukemia cell line Nalm-6 cells and its mechanisms in order to provide the evidence of target therapy on B lineage leukemia and lymphoma.</p><p><b>METHODS</b>2E8-Genistein immunotoxin was generated by conjugating Mab 2E8 with a tyrosine kinase inhibitor, Genistein (Gen) via the Sulfo-SANPAH, an ultra-violet sensitive reagent. Nalm-6, a CD19+ B cell leukemia cell line, was used as target cells, while Molt-3, a CD19-T cell leukemia cell line, was taken as the negative control. The morphology of the cells was observed under the reverted reversed light microscope and the viability was checked with either trypan blue exclusion or MTT methods. Two-color flow cytometry was applied to study the mechanism of cell killing.</p><p><b>RESULTS</b>After 24 hours of culture, 2E8-Genistein showed marked target killing on Nalm-6 cells at nine different concentrations from 20 nmol/L through 100 nmol/L with cell survival rates from (71.8 +/- 7.9)% down to (16.6 +/- 12.9)%, respectively (n = 3), which were all significantly lower than that of control group (100 +/- 13.9)% (P < 0.05). The killing effect was even more significant when the concentration was over 80 nmol/L. The growth inhibition rates of this immunotoxin on Nalm-6 cells were 82%, 84% and 94%, respectively at 24, 48 and 72 hours of culture in a time dependent manner. Significant difference was observed between the cell growth curve of Nalm-6 cultured with 100 nmol/L of 2E8-Gen and those of Nalm-6 cultured with medium (blank), PBS (negative control) or the same concentration of pure 2E8 antibody (negative control) groups (F = 152.15, P = 2.15 x 10(-7)), but there was no significant difference among the three control groups (F = 1.51, P = 0.29). When Molt-3 cells were used as target cells, the cell growth curves of Molt-3 cultured with 2E8-Gen (100 nmol/L) and with negative control of blank did not show any significant difference (F = 0.34, P = 0.59). PI/FITC Annexin V double staining analysis with flow cytometry showed that the positive rate (33.45 +/- 8.77)% of early apoptosis on Nalm-6 cells induced by 100 nmol/L of 2E8-Genistein was significantly higher than that of negative control of blank (10.44% +/- 1.28%, t = -4.39, P = 0.001) at 24 hours of culture.</p><p><b>CONCLUSION</b>2E8-Genistein immunotoxin can significantly target the Nalm-6 cells in vitro in a time response manner and the apoptosis induction is involved in the course of this killing effect.</p>

Efficacy of chemotherapy using 10-hydroxycamptothecin on recurrent or refractory neuroblastoma in children / 中国当代儿科杂志

<p><b>OBJECTIVE</b>The patients with recurrent or refractory neuroblastoma have a very poor prognosis and high mortality. 10-hydroxycamptothecin (HCPT) is a new agent extracted from comptotheca acuminate, a native plant. It has been shown to be very effective in some solid tumors such as gastric and colon cancers, lung cancers and ovary cancers. However, its efficacy in neuroblastoma has not been determined. This study aimed to investigate the therapeutic effects of HCPT in the treatment of recurrent or refractory neuroblastoma in children.</p><p><b>METHODS</b>Ten children with recurrent neuroblastoma and two children with refractory neuroblastoma were treated with HCPT. Of them, 5 children with recurrent neuroblastoma were treated with HCPT alone, and the other 7 patients received combination chemotherapy of HCPT plus other agents. The HCPT alone treatment group was injected with HCPT (7.5 mg/m2 daily) for 14 consecutive days. The combination chemotherapy group was alternately treated with the modified new protocol A1 (cyclophosomide 1 200 mg/m2 on day 1, etoposide 100 mg/m2 on days 1-5, HCPT 5 mg/m2 on days 1-3, cisplatin 90 mg/m2 on day 4) and the modified protocol B (ifosfomide 1.5 g/m2 on days 1-5, HCPT 5 mg/m2 on days 1-3, carboplatin 450 mg/m2 on day 2).</p><p><b>RESULTS</b>Four patients (33.3%) achieved partial remission and 8 patients (66.7%) had stable disease. The median remission duration was 3.5 months (2-5 months). HCPT treatment as a single agent resulted in mild side effects. Myelosuppression and digestive disorders were found as the main adverse events in the combined chemotherapy group. No chemotherapy related deaths were found.</p><p><b>CONCLUSIONS</b>HCPT is safe and effective in the treatment of recurrent or refractory neuroblastoma. The toxicities of HCPT are tolerable. The long-term efficacy of HCPT warrants further research.</p>

Eukaryotic expression and determination of ZCH-7-2F9 single chain antibody against human CD14 / 中华儿科杂志

<p><b>OBJECTIVE</b>Acute monocytic leukemia (AML)-M5 is the common type of acute myeloid leukemias in children. Studies have shown that there are abundant lipopolysaccharide (LPS) receptor (designated as CD14) molecules on the cell membrane of M5 cells and they play an important role in the diagnosis of M5, since they can be recognized and bound by mouse-anti-human CD14 monoclonal antibody (McAb). However, mouse-originated antibodies are largely not suitable for clinical application due to the severe side effects, thus "humanized antibody" is desired. As the first step for developing humanized antibody, the construction and expression of single chain antibody (scFv) with functional protein are necessary. The present study aimed to express ZCH-7-2F9 ScFv (scFv(2F9)) in eukaryotic cells and obtain the scFv(2F9) protein with a high biological activity.</p><p><b>METHODS</b>Four primers were synthesized to construct the eukaryotic expressional vector, which included SfiI and EcoRI enzyme cleaving site, 6 x His and stop code TGA sequences. scFv(2F9) gene was amplified through splicing by overlap extension (SOE) using the high fidelity Taq polymerase. Positive recombinants (pSectag2A/scFv(2F9)) were identified through enzyme cleaving and sequenced before expression and were transformed into Chinese hamster ovary (CHO) cells for expression. Western-Blot and flow cytometry (FCM) were carried out to determine the relative molecular mass (Mr) and binding activity of scFv(2F9).</p><p><b>RESULTS</b>The cloned scFv(2F9) gene was identified to be functional by sequencing and expressing. The interested protein could be detected in the culture supernatant of transformed CHO cells with an Mr of 31 000. The blocking test showed that the positive cell percentages, the mean fluorescence intensity (MFI) and the peak of channel (peak Ch) were reduced by 90.02%, 63.30% and 63.38%, respectively after blocking with scFv(2F9), while those were 4.55%, 10.09% and 5.02% after blockage using the supernatant from the CHO cells transfected with blanked vector pSectag2A.</p><p><b>CONCLUSIONS</b>The scFv(2F9) against human CD14 antigen was successfully expressed in eukaryotic cells and showed a high biological activity, which may be useful for the further studies on its humanized antibodies.</p>

Preparation of the immunotoxin 2E8-norcantharidin and its targeting killing effect in vitro / 中华儿科杂志

<p><b>OBJECTIVE</b>Monoclonal antibody (mAb) conjugated with certain toxin to generate immunotoxin bears an important and promising effect as a new therapy for patients with hematopoietic malignancies. However, most toxic moieties conjugated with antibody proteins reported in the literature were toxic proteins which presented immunogenicity to patients capable of inducing anti-toxin antibody. Norcantharidin (NCTD) is a small molecule toxin. It does not have the immunogenicity to human body so that it bears a promising potential for development of new targeting drug. In this study, a new clone of self-made anti-CD19 mAb named ZCH-4-2E8 conjugated with NCTD was used to investigate its targeting efficacy against CD19+ lymphoid malignant Nalm-6 cells in vitro to provide the experimental data for the further development of this new targeting agent.</p><p><b>METHODS</b>A monoclonal antibody named 2E8 was prepared from mouse ascites and purified by gel chromatography. The purity of the antibody protein was checked by SDS-PAGE assay. Immunotoxin 2E8-NCTD was successfully generated through conjugating CD19 mAb protein and Norcantharidin by the activated ester method. The binding activity of the immunoconjugate (2E8-NCTD) against CD19 antigens on cell surface and the expression levels of CD19 antigens on Nalm-6 and K562 cells were examined by flow cytometry. Comparisons of the inhibitory effects among PBS, purified 2E8 antibody, norcantharidin and immunotoxin 2E8-NCTD groups on cell growth of either Nalm-6 cells or K562 cells were made.</p><p><b>RESULTS</b>The purity of the purified 2E8 antibody was higher than 99.00% demonstrated by SDS-PAGE assay. 2E8 antibody in the supernatant reacted with 99.34% of Nalm-6 cells, while only 0.98% of K562 cells reacted with this antibody. The newly generated immunotoxin (2E8-NCTD) had a positive rate of 99.90% on Nalm-6 cells with little reduction of binding activity. From the in vitro study, both 2E8-NCTD and norcantharidin were shown to have significant inhibitory effects on the growth of CD19+ Nalm-6 cells (P < 0.001), while the purified 2E8 antibody did not show any significant influences on the growth of Nalm-6 cells. Since no significant inhibitory effects were identified among immunotoxin 2E8-NCTD, 2E8 antibody and control groups on CD19(-) K562 cells, a significant targeting effect of the 2E8-NCTD against Nalm-6 cells was confirmed.</p><p><b>CONCLUSIONS</b>The immunotoxin 2E8-NCTD was successfully synthesized by activated ester method with an excellent targeting killing effect on CD19+ Nalm-6 leukemia cells in vitro, which provides some experimental data for the further development of this new targeting agent.</p>

Establishment of animal model with B lineage acute leukemia in nude mice for evaluation of new therapeutic agents / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To establish an acute leukemia animal model for testing new therapeutic agents in vivo.</p><p><b>METHODS</b>Nude mice were intraperitoneally injected with 2 mg cyclophosphamide, 24 h later 5 x 10(6) acute B-cell leukemia Nalm-6 cells was inoculated via the tail vein, then monitored daily. When animals were paralyzed or dying, the organs including the liver, spleen, lung, heart, kidney, brain, bone marrow, pancreas, testes were removed and fixed with formalin, examined by routine histopathology.</p><p><b>RESULTS</b>After Nalm-6 cells were inoculated the mean survival of mice were( 19.4+/-0.55)d (n=6). The paralysis of mice was followed by weight loss, bent spines, hogback, cachexia and death. Histopathological examination showed that the tumor cells infiltrated liver, spleen, kidney, lung, meninges, interior cerebrum, the liver and kidney were the most affected organs.</p><p><b>CONCLUSION</b>B lineage acute leukemia animal model has been successfully established in the nude mice, which is suitable for testing new therapeutic agents.</p>

Construction and expression of prokaryotic vector of single chain antibody derived from a new clone of anti-CD14 antibody ZCH-7-2F9 / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To construct a prokaryotic vector of ZCH-7-2F9 single chain antibody (ScFv2F9) and to obtain the ScFv2F9 protein with biological activity for further studies.</p><p><b>METHODS</b>Primers were synthesized according to the gene sequence of ScFv2F9, four tandem glycin and one serine (G4S) 3linker and multiple cloning site(MCS) of pIVEX2.3-MCS vector, which included NdeI and SmaI enzyme cleaving sites. ScFv2F9 gene was amplified through splicing by overlap extension (SOE) using the high fidelity Taq polymerase. Then the gene was cloned to pGEM-T easy and pIVEX2.3-MCS vectors. Positive recombinants (pIVEX2.3-MCS/ScFv2F9) were identified through enzyme cleaving and sequenced before expression. The recombinant plasmids were transfected into E.coli BL21star(DE3)plysS for expression. After purification with Ni+resin and renaturation in vitro, the relative molecular mass (Mr) and the binding activity of the interesting protein were determined by SDS-PAGE and flow cytometry (FCM), respectively.</p><p><b>RESULT</b>The cloned ScFv2F9 gene was identified to be functional by sequencing and expressing. The interesting protein was detected in inclusion body with a Mr of 31 000. The blocking test showed that the positive cell percentage, the mean fluorescence intensity (MFI) and the peak of channel (peak Ch) were reduced by 11.73%, 11.96% and 31.57%, respectively after once blockage by scFv2F9 protein, and 26.44 %, 21.75 % and 42.11 % after blockage twice.</p><p><b>CONCLUSION</b>The ScFv2F9 against human CD14 antigen has been successfully expressed in prokaryotic cells with partial biological activity, which lays the foundation for further studies on its immunotoxin and other kinds of engineered antibodies.</p>