[Establishment of leukemia cell model with inducible AML1-ETO expression and its effect on fatty acid metabolism in leukemia cells]

Objective: To investigate the effect of the AML1-ETO (AE) fusion gene on the biological function of U937 leukemia cells by establishing a leukemia cell model that induces AE fusion gene expression. Methods: The doxycycline (Dox) -dependent expression of the AE fusion gene in the U937 cell line (U937-AE) were established using a lentivirus vector system. The Cell Counting Kit 8 methods, including the PI and sidanilide induction, were used to detect cell proliferation, cell cycle-induced differentiation assays, respectively. The effect of the AE fusion gene on the biological function of U937-AE cells was preliminarily explored using transcriptome sequencing and metabonomic sequencing. Results: ①The Dox-dependent Tet-on regulatory system was successfully constructed to regulate the stable AE fusion gene expression in U937-AE cells. ②Cell proliferation slowed down and the cell proliferation rate with AE expression (3.47±0.07) was lower than AE non-expression (3.86 ± 0.05) after inducing the AE fusion gene expression for 24 h (P<0.05). The proportion of cells in the G(0)/G(1) phase in the cell cycle increased, with AE expression [ (63.45±3.10) %) ] was higher than AE non-expression [ (41.36± 9.56) %] (P<0.05). The proportion of cells expressing CD13 and CD14 decreased with the expression of AE. The AE negative group is significantly higher than the AE positive group (P<0.05). ③The enrichment analysis of the transcriptome sequencing gene set revealed significantly enriched quiescence, nuclear factor kappa-light-chain-enhancer of activated B cells, interferon-α/γ, and other inflammatory response and immune regulation signals after AE expression. ④Disorder of fatty acid metabolism of U937-AE cells occurred under the influence of AE. The concentration of the medium and short-chain fatty acid acylcarnitine metabolites decreased in cells with AE expressing, propionyl L-carnitine, wherein those with AE expression (0.46±0.13) were lower than those with AE non-expression (1.00±0.27) (P<0.05). The metabolite concentration of some long-chain fatty acid acylcarnitine increased in cells with AE expressing tetradecanoyl carnitine, wherein those with AE expression (1.26±0.01) were higher than those with AE non-expression (1.00±0.05) (P<0.05) . Conclusion: This study successfully established a leukemia cell model that can induce AE expression. The AE expression blocked the cell cycle and inhibited cell differentiation. The gene sets related to the inflammatory reactions was significantly enriched in U937-AE cells that express AE, and fatty acid metabolism was disordered.

[Dasatinib combined with multi-agent chemotherapy regimen in newly diagnosed Philadelphia chromosome-positive acute lymphoblastic leukemia: a prospective study from a single center]

目的

评价达沙替尼联合多药化疗方案在Ph染色体阳性急性淋巴细胞白血病（Ph⁺ ALL）患者中的疗效及安全性。

方法

前瞻性、单臂、开放的临床研究。2016年1月至2018年4月中国医学科学院血液病医院收治的30例初诊成人Ph⁺ ALL患者入组。采用多药化疗方案，标准诱导化疗为期4周，自诱导化疗第8天开始口服达沙替尼（商品名依尼舒，正大天晴药业集团股份有限公司产品）100 mg/d，持续应用至整体治疗结束。有条件和意愿进行移植者，可进行异基因造血干细胞移植或自体造血干细胞移植。

结果

所有30例患者在诱导治疗4周后均达到血液学完全缓解（HCR），累积完全分子学反应（MCR）率为70.0％（21/30）。中位随访时间为37.8（32.0～46.6）个月。3年总生存（OS）率为68.1％，3年无血液学复发生存（HRFS）率为61.6％。63.3％的患者在治疗3个月时达到主要分子学反应（MMR）（其中有43.3％患者达到MCR）。6个月时60.0％的患者达到MCR，达到MCR的患者具有更好的OS（P＝0.004）、HRFS（P＝0.049）和EFS（P＝0.001）。15例（50.0％）患者在第1次HCR期内进行移植，移植组患者HRFS（P＝0.030）和EFS（P＝0.010）优于化疗组。

结论

达沙替尼联合多药化疗方案治疗初诊Ph⁺ALL安全有效。

临床试验注册

ClinicalTrials.gov，NCT02523976。

[Impact of duration of antibiotic therapy on the prognosis of patients with acute myeloid leukemia who had Gram-negative bloodstream infection in consolidation chemotherapy]

目的

分析巩固化疗期间伴发革兰阴性菌（G⁻菌）血流感染的急性髓系白血病（AML）患者抗感染疗程对感染转归的影响。

方法

回顾性分析2010年9月至2016年1月入组“依据危险度分层对急性髓系白血病优化治疗的研究”临床试验的591例AML（非急性早幼粒细胞白血病）患者的血流感染资料，将其中巩固化疗期间发生G⁻菌血流感染且持续发热时间<7 d的114例次血流感染（89例患者）纳入研究，分析抗感染疗程对感染转归的影响。

结果

114例次血流感染发生时，患者中位ANC为0（0~5.62）×10⁹/L，中性粒细胞缺乏（粒缺）持续的中位时间为9（3~26）d，抗感染治疗的中位时间为7（4~14）d。抗感染疗程≤7 d与>7 d组比较，停药后3 d内再发热比例、再次发生相同菌株血流感染比例分别为1.2%对3.0%、18.5%对21.2%，差异均无统计学意义（P=0.522，OR=0.400，95%CI 0.024~6.591；P=0.741，OR=0.844，95%CI 0.309~2.307）。同时，两组患者均未发生7 d及30 d内感染相关死亡。且倾向性评分平衡患者特征及用药差异因素后，抗感染疗程≤7 d较>7 d组再次发生相同菌株血流感染比例仍无明显增高（P=0.525，OR=0.663，95%CI 0.187~2.352）。

结论

对于巩固化疗期间伴发G⁻菌血流感染的AML患者，若发热时间<7 d，敏感抗菌药物治疗7 d后停药并不增加停药后3 d内再发热，粒缺期再次出现相同菌株血流感染及感染相关7 d、30 d内死亡风险。提示短疗程抗感染方案可以成为巩固化疗伴发G⁻菌血流感染AML患者感染控制情况下合理的治疗选择。

[Primary antifungal prophylaxis with posaconazole plays a pivotal role during chemotherapy of acute myeloid leukemia]

Objective: To evaluate the incidence of invasive fungal infections (IFI) and usage of intravenous antifungal drugs during remission induction chemotherapy in patients with acute myeloid leukemia (AML) under primary antifungal prophylaxis with posaconazole. Methods: Clinical records from newly diagnosed AML patients above 15 years old in one single center from February 2014 to January 2016 were retrospectively reviewed and analyzed, excluding acute promyelocytic leukemia. The incidence of IFI and usage of intravenous antifungal drugs were investigated between control group (not receiving any broad spectrum antifungal prophylaxis) and treatment group (receiving posaconazole as primary prophylaxis). Results: A total of 147 newly diagnosed AML patients were enrolled. Of them, 81 received prophylaxis with posaconazole, and 66 did not receive broad-spectrum antifungal treatment. 7 IFI occurred in posaconazole group, and all were possible cases; 19 IFI occurred in control group (3 proven, 4 probable, 12 possible). The incidence of IFI was significantly lower in treatment group than that in control group (8.6% vs 28.8%, χ(2)=10.138, P=0.001). Usage of intravenous antifungal drugs was significantly decreased in posaconazole group (18.5% vs 50.0%, χ(2)=16.390, P<0.001). Conclusion: Prophylaxis with posaconazole coulf prevent IFI and reduce usage of intravenous antifungal drugs significantly during remission induction chemotherapy in AML patients.

[Characteristics and prognosis in adult acute myeloid leukemia patients with MLL gene rearrangements]

Objective: To analyze the clinical and laboratory characteristics, and prognosis of adult acute myeloid leukemia (AML) patients with MLL gene rearrangements. Methods: The medical records of 92 adult AML patients with MLL gene rearrangements from January 2010 to December 2016 were retrospectively analyzed. Results: 92 cases (6.5%) with MLL gene rearrangements were identified in 1 417 adult AML (Non-M(3)) patients, the median age of the patients was 35.5 years (15 to 64 years old) with an equal sex ratio, the median WBC were 21.00(0.42-404.76)×10(9)/L, and 78 patients (84.8%) were acute monoblastic leukemia according to FAB classification. Eleven common partner genes were detected in 32 patients, 9 cases (28.1%) were MLL/AF9(+), 5 cases (15.6%) were MLL/AF6(+), 5 cases (15.6%) were MLL/ELL(+), 2 cases (6.3%) were MLL/AF10(+), 1 case (3.1%) was MLL/SETP6(+), and the remaining 10 patients' partner genes weren't identified. Of 92 patients, 83 cases with a median follow-up of 10.3 (0.3-74.0) months were included for the prognosis analysis, the complete remission (CR) rate was 85.5% (71/83), the median overall survival (OS) and relapse free survival (RFS) were 15.4 and 13.1 months, respectively. Two-year OS and RFS were 36.6% and 29.5%, respectively. Of 31 patients underwent allogeneic hematopoietic stem-cell transplantation (allo-HSCT), two-year OS and RFS for patients received and non-received allo-HSCT were 57.9% and 21.4%, 52.7% and 14.9%, respectively (P<0.001). Among patients with partner genes tested, 9 of 32 cases (28.1%) were MLL/AF9(+), the median follow-up was 6.0(4.1-20.7) months. 3 patients with MLL/AF9 underwent allo-HSCT. 23 cases (71.9%) were non- MLL/AF9(+), the median follow-up was 7.8 (0.3-26.6) months. 14 patients (60.1%) with non-MLL/AF9 underwent allo-HSCT. One-year OS for patients with MLL/AF9 and non-MLL/AF9 were 38.1% and 55.5%, respectively (P=0.688). Multivariate analysis revealed that high WBC (RR=1.825, 95% CI 1.022-3.259, P=0.042), one cycle to achieve CR (RR=0.130, 95% CI 0.063-0.267, P<0.001), post-remission treatment with allo-HSCT (RR=0.169, 95% CI 0.079-0.362, P<0.001) were independent prognostic factors affecting OS. Conclusions: AML with MLL gene rearrangements was closely associated with monocytic differentiation, and MLL/AF9 was the most frequent partner gene. Conventional chemotherapy produced a high response rate, but likely to relapse, allo-HSCT may have the potential to further improve the prognosis of this group of patients.

[Prediction of outcome in acute myeloid leukemia by measurement of WT1 expression as a basic marker of minimal residual disease]

Objective: To probe the potential utility of Wilms tumor 1 (WT1) as a marker of minimal residual disease (MRD) in acute myeloid leukemia (AML) to estimate the relapse-predicting cut-off value. Methods: Quantitative assessment of bone marrow WT1 mRNA level was preformed using real-time quantitative reverse transcription polymerase chain reaction (RQ-RT-PCR) assay. The expression levels of WT1 dynamically measured with RQ-RT-PCR were retrospectively analyzed in 121 AML cases (not including acute promyelocytic leukemia) achieving complete remission (CR) after induction therapy followed by consolidation therapy. By comparing WT1 levels of patients with different post-therapy outcomes, the investigators used the receiver operating characteristic (ROC) curve to determine WT1 threshold so as to predict their clinical relapses. Then prognoses and the significance of intervention were analyzed between WT1 positive and negative patients according to the cut-off value of WT1. Results: According to ROC curve, WT1 level higher than 2.98% predicted the possibility of relapse. For simplicity and clinical application, 3.00% was used as the cut-off value of WT1 level for relapse. WT1 levels in 41 patients at diagnosis were detected, meanwhile 3 patients whose WT1 levels at diagnosis below 3.00% were excluded, then the median WT1 level of the rest 38 patients at diagnosis was 44.09% (range 7.19%-188.06%) . The median WT1 level in remission was 0.48% (352 samples, range 0-8.41%) . The median WT1 level at diagnosis was higher than that in remission. Excluding the 3 patients with WT1 level at diagnosis under 3.00%, the relapse rate of WT1 positive group (>3.00% during consolidation phase and follow-up) and WT1 negative group (≤3.00%) was 70.0% (14/20) and 12.2% (12/98) respectively (P<0.001) . The median time from WT1 positivity to clinical relapse was 58 days. Conclusions: WT1 expression level above 3.00% was associated with markedly high risk of relapse, which could be as a useful marker for monitoring MRD following consolidation therapy.

[Clinical features and prognosis in CD10(-) pre-B acute lymphoblastic leukemia]

目的

分析CD10阴性的前B急性淋巴细胞白血病（CD10⁻pre B-ALL）患者的临床特征和预后。

方法

对6例成人CD10⁻ pre B-ALL患者的临床和实验室资料进行回顾性分析，结合文献复习明确该类型患者的临床特征及预后。

结果

CD10⁻pre B-ALL占ALL的1.5%（6/409），占B-ALL的1.8%（6/343），占pre B-ALL的11.5%（6/52）。6例患者均为男性，中位年龄为33.5岁，起病时中位WBC为101.78×10⁹/L，所有患者均伴有MLL-AF4融合基因表达。5例患者经1个疗程诱导化疗即获得完全缓解（CR），1例患者经3个疗程化疗后才获得CR。2例患者在CR₁期行异基因造血干细胞移植（allo-HSCT），1例患者CR后短期内即复发，在CR₂期行allo-HSCT。1例患者正在等待移植。2例未移植患者1例复发死亡，1例尚处于缓解状态。

结论

CD10⁻pre B-ALL是一类具有独特临床特征的成人ALL亚型，发生率较低，常见于男性，起病时白细胞水平较高，MLL-AF4融合基因表达率高，常规化疗具有较高的缓解率，但易复发，allo-HSCT有可能改善其预后。

[Homoharringtonine in newly diagnosed acute promyelocytic leukemia treatment: a prospective, randomized controlled trial]

OBJECTIVE

To compare the efficacy and toxicities of combining homoharringtonine (HHT)±daunorubicin (DNR) with all-trans-retinoic acid (ATRA) based therapy and DNR plus ATRA based therapy in newly diagnosed low/intermediate risk acute promyelocytic leukemia (APL).

METHODS

A total of 96 newly diagnosed patients with APL were randomized to HHT group, DNR group and HHT+ DNR group prospectively. The complete remission (CR) rate, the overall survival (OS) and event-free survival (EFS) of three groups were analyzed.

RESULTS

There were 31 patients in HHT group, 33 patients in DNR group and 32 patients in HHT+ DNR group. The baseline characteristics of three groups were similar. No patient died during induction therapy. The morphologic CR rate was 100.0%. The median time to peak WBC counts in HHT+DNR group (4 days, range: 1-23 days) was significantly shorter than that in HHT group (9 days, range: 1-27 days) (P=0.008) and DNR group (7 days, range: 1-27 days) (P=0.240). There was no difference among three groups about the incidence of differentiation syndrome, the median interval to achieve CR, peak WBC counts and transfusions (P >0.05). All patients achieved complete molecular remission (CMR) during consolidation therapy. The interval to achieve CMR was no significantly difference among three groups (P >0.05). The 3-year OS rates for HHT group, DNR group and HHT+DNR group were 95.0%, 100.0% and 91.0%, respectively (P=0.595). The 3-year EFS rates for three groups were 93.0%, 90.0% and 85.0% (P=0.382). No difference was found in the incidence of adverse events among three groups (P >0.05).

CONCLUSIONS

Similar to DNR plus ATRA based therapy, HHT plus ATRA based induction and consolidation therapy should be one of highly-efficient treatment options for newly diagnosed APL. Clinical trial registration Chinese Clinical Trial Registry, ChiCTR-TRC-12002628.

Genetic engineering of avian pathogenic E. coli to study the functions of FimH adhesin

Adhesion of pathogen to host cells is an important prerequisite for successful colonization and establishment of the pathogenesis. The aim of this study is to examine the function of FimH adhesin in the adherence of avian pathogenic E. coli to porcine intestinal epithelial cell lines (IPEC-J2) and human lung epithelial cell line (A549) in an in vitro infection model. Three strains of avian pathogenic Escherichia coli (APEC) and one strain of non-pathogenic E coli were used. The isogenic FimH mutants were constructed by lambda Red-mediated recombination system. The wild types and mutants strains were adhered to the host cells with different adherence patterns in certain incubation time. The results demonstrated that the adherence of the isogenic FimH mutants to the porcine intestinal epithelial cells (IPEC-J2) were similar to those of wild types. However, the adherences of isogenic FimH mutants to human lung epithelial cells (A549) were significantly different from the wild types. A549 cell can be used as a type of cell model for colonization of the chicken extraintestinal. FimH offers a unique opportunity to investigate the role of the strength of adhesion independently from the many other factors that may affect surface colonization.