Library-Assisted Evolution in Eukaryotic Cells Yield Adenine Base Editors with Enhanced Editing Specificity.

The current-generation adenine base editor (ABE) ABE8e, which has evolved from the prokaryotic evolution system, exhibits high efficiency in mediating A-to-G conversion and is presumed to be promising for gene therapy. However, its much wider editing window and substantially higher off-target editing activity restricted its applications in precise base editing for therapeutic use. This study uses a library-assisted protein evolution approach using eukaryotic cells to generate ABE variants with improved specificity and reduced off-target editing while maintaining high activity in human cells. The study generated an expanded set of ABEs with efficient editing activities and chose four evolved variants that offered either similar or modestly higher efficiency within a narrower editing window of protospacer position ≈4-7 compared to that of ABE8e in human cells, which would enable minimized bystander editing. Moreover, these variants resulted in reduced off-target editing events when delivered as plasmid or mRNA into human cells. Finally, these variants can install both disease-suppressing mutations and disease-correcting mutations efficiently with minimal undesired bystander editing making them promising approaches for specific therapeutic edits. In summary, the work establishes a mutant-library-assisted protein evolution method in eukaryotic cells and generates alternative ABE variants as efficient tools for precise human genome editing.

Development of a nomogram to predict the risk of secondary failure of platelet recovery in patients with ß-thalassemia major after hematopoietic stem cell transplantation: a retrospective study.

Background: Secondary failure of platelet recovery (SFPR) is a common complication that influences survival and quality of life of patients with ß-thalassemia major (ß-TM) after hematopoietic stem cell transplantation (HSCT). Objectives: A model to predict the risk of SFPR in ß-TM patients after HSCT was developed. Design: A retrospective study was used to develop the prediction model. Methods: The clinical data for 218 ß-TM patients who received HSCT comprised the training set, and those for another 89 patients represented the validation set. The least absolute shrinkage and selection operator regression algorithm was used to identify the critical clinical factors with nonzero coefficients for constructing the nomogram. Calibration curve, C-index, and receiver operating characteristic curve assessments and decision curve analysis (DCA) were used to evaluate the calibration, discrimination, accuracy, and clinical usefulness of the nomogram. Internal and external validation were used to test and verify the predictive model. Results: The nomogram based on pretransplant serum ferritin, hepatomegaly, mycophenolate mofetil use, and posttransplant serum albumin could be conveniently used to predict the SFPR risk of thalassemia patients after HSCT. The calibration curve of the nomogram revealed good concordance between the training and validation sets. The nomogram showed good discrimination with a C-index of 0.780 (95% CI: 70.3-85.7) and 0.868 (95% CI: 78.5-95.1) and AUCs of 0.780 and 0.868 in the training and validation sets, respectively. A high C-index value of 0.766 was reached in the interval validation assessment. DCA confirmed that the nomogram was clinically useful when intervention was decided at the possibility threshold ranging from 3% to 83%. Conclusion: We constructed a nomogram model to predict the risk of SFPR in patients with ß-TM after HSCT. The nomogram has a good predictive ability and may be used by clinicians to identify SFPR patients early and recommend effective preventive measures.

Expression signature of ten small nuclear RNAs serves as novel biomarker for prognosis prediction of acute myeloid leukemia.

This study aimed to screen for small nuclear RNAs (snRNAs) associated with the prognosis of acute myeloid leukemia (AML) by using The Cancer Genome Atlas (TCGA) whole-transcriptome sequencing dataset. A total of 130 AML patients from TCGA cohort with complete prognostic information and transcriptome data were enrolled in the current study. Comprehensive survival and functional enrichment analyses were performed to explore the prognostic value and potential biological functions of prognostic snRNAs in AML patients. In the current study, we screened 72 snRNAs that were notably associated with the clinical outcome of AML and developed an expression signature consist of ten snRNAs, that can be accurately applied to assess the overall survival of AML patients. Functional mechanism analysis revealed that this expression signature may be strongly linked to some classical tumor-associated pathways, such as Notch and Wnt pathways, as well as being closely related to B and T cell receptor pathways. Furthermore, we screened six compounds (chicago sky blue 6 B, 5230742, clorsulon, nefopam, nicardipine, and streptomycin) that may serve as targeted therapeutic drugs for AML using connectivity maps. Tumor immunoassays indicated significant differences in the immune microenvironment of the bone marrow tissue between high-risk and low-risk AML patients. Immune infiltration analysis also revealed significant differences in the abundance of multiple immune cells in the bone marrow of the two groups of AML patients groups. In conclusion, our results revealed a novel prognostic expression signature of AML consisting of ten snRNAs, and we conducted a preliminary exploration of its potential biological functions and tumor immunity.

Autologous followed by allogeneic versus tandem-autologous transplantation in high-risk, newly diagnosed multiple myeloma: a systematic review and meta-analysis.

OBJECTIVES: High-risk multiple myeloma (HRMM) is associated with poor survival, despite many advances in antimyeloma strategies. Autologous followed by allogeneic stem cell transplantation (auto-allo-SCT) has yielded controversial results compared to tandem autologous stem cell transplantation (auto-SCT) in patients with HRMM. We conducted this meta-analysis to compare the efficacy and safety of auto-allo-SCT and tandem-auto-SCT in patients with HRMM. METHODS: Embase, Cochrane Library, and PubMed databases were searched until March 2023. Prospective or retrospective studies comparing the effects of auto-allo-SCT and tandem-auto-SCT were included. Hazard ratios (HRs) and 95% confidence intervals (CIs) for time-to-event outcomes, and odds ratios (ORs) and 95%CIs for dichotomous outcomes were pooled using random-effects models. RESULTS: Three studies involving 491 patients were included. Despite auto-allo-SCT seemed to be associated with improvements in progression-free survival (PFS) (HR [95%CI], 0.71 [0.51-1.00]) and complete response (CR) (OR [95%CI], 3.16 [1.67-5.99]), and reduced relapse/progression rates (47% vs. 55%) in comparison with tandem-auto-SCT, no marked improvement in overall survival (OS). In comparison to tandem-auto-SCT, patients assigned to auto-allo-SCT exhibited a higher risk of transplant-related mortality (TRM) (11.9% vs. 4.1%) and non-relapse mortality (NRM) (12.3% vs. 3.1%). CONCLUSION: Auto-allo-SCT seemed to be associated with improvements in PFS and CR when compared to tandem-auto-SCT in patients with HRMM, but it did not lead to a significant improvement in OS. Furthermore, patients in the auto-allo-SCT group were at a higher risk of developing TRM and NRM. Auto-allo-SCT transplantation should not be routinely incorporated into HRMM therapy but rather should be considered investigational.

A clinical analysis of Candida tropicalis bloodstream infections associated with hematological diseases, and antifungal susceptibility: a retrospective survey.

Summary objective: To assess the clinical features and outcomes of hematological disease patients with Candida tropicalis bloodstream infections and determine the antifungal susceptibility of C. tropicalis. Methods: This is a retrospective, single-center, observational study conducted in the Department of Hematology at The First Affiliated Hospital of Guangxi Medical University from January 2013 to December 2021. A total of 26 hematological disease patients with C. tropicalis bloodstream infections were enrolled, and their clinical features, treatment plans, and prognoses were assessed. Univariate analysis was performed by Kaplan-Meier analysis and multivariate analysis was conducted using a Cox regression model. The antifungal susceptibility of C. tropicalis was determined from patient blood cultures. Results: The patients had a mean age of 35 years (range: 10-65 years), 50% were male (13/26) and 88.5% had hematologic malignancies (23/26) while the remaining three patients included two cases of severe aplastic anemia and one case of ß-thalassemia. All patients had neutropenia. Seven patients were initially given azole alone (26.9%), five of whom failed treatment and died (71.4%). Fifteen patients were treated with echinocandin (57.7%), three of whom failed treatment and died (20.0%), and eight patients were treated with amphotericin B (30.8%), two of whom failed treatment and died (25.0%). The total and attributable mortality rates were 42.3 and 34.6%, respectively. Univariate analysis showed that there are six risk factors for attributable deaths among hematological disease patients with C. tropicalis blood infections. These risk factors included septic shock, Pitt bacteremia scores ≥4, procalcitonin levels ≥10 ng/mL, positive plasma (1,3)- ß-D glucan assay, serum albumin levels <30.0 g/L, time from fever to antifungal treatment initiation ≥5 days and time between neutropenia and antifungal treatment ≥10 days. Moreover, skin and mucosal infections and a treatment schedule that included amphotericin B and drug combinations are protective factors for attributable deaths. Multivariate analysis showed that septic shock (p = 0.006) was an independent risk factor for attributable death. All isolates were sensitive to flucytosine and amphotericin B. The intermediate or resistance of C. tropicalis to fluconazole, itraconazole and voriconazole were 41.7, 50, and 41.7%, respectively. Conclusion: Hematological disease patients with C. tropicalis bloodstream infections had a high mortality rate, and early antifungal therapy significantly reduced mortality. Candida tropicalis was highly resistant to azole drugs and sensitive to flucytosine and amphotericin B. According to our study, the preferred agent is amphotericin B and drug combinations should be considered for severe infections.

Poor pretransplantation minimal residual disease clearance as an independent prognostic risk factor for survival in myelodysplastic syndrome with excess blasts: A multicenter, retrospective cohort study.

BACKGROUND: Minimal residual disease (MRD) is an important prognostic factor for survival in adults with acute leukemia. The role of pretransplantation MRD status in myelodysplastic syndrome with excess blasts (MDS-EB) is unknown. This study retrospectively analyzed the relationship between pretransplantation MRD status and long-term survival. MATERIALS AND METHODS: Patients with MDS-EB who underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT) from March 5, 2005, to November 8, 2020, were included. The relationship between pretransplantation MRD status and long-term survival was analyzed using univariate and multivariate logistic regression models. RESULTS: Of 220 patients with MDS-EB who underwent allo-HSCT, 198 were eligible for inclusion in this multicenter, retrospective cohort study. Complete remission was attained in 121 (61.1%) patients, and 103 patients underwent detection of MRD pretransplantation, with 67 patients being MRD-positive and 36 patients being MRD-negative. The median follow-up time was 16 months, the median age was 41 years (6-65 years), and 58% of the patients were men. The 3-year disease-free survival (DFS) and overall survival (OS) probabilities for all patients were 70.1% and 72.9%, respectively. For patients in complete remission, the 3-year DFS and OS probabilities were 72.2% and 74.8%, respectively. Further analysis found that the 3-year DFS rates of MRD-negative and MRD-positive patients were 85.6% and 66.5% (p = .045), respectively, whereas the 3-year OS rates were 91.3% and 66.4% (p = .035), respectively. Univariate and multivariate analyses showed that poor pretransplantation MRD clearance was an independent prognostic risk factor for DFS and OS. CONCLUSION: Poor pretransplantation MRD clearance is an independent prognostic risk factor for long-term survival after allo-HSCT for patients with MDS-EB. PLAIN LANGUAGE SUMMARY: Poor minimal residual disease clearance pretransplanation is an independent prognostic risk factor for long-term survival after allogeneic hematopoietic stem cell transplantation for patients with myelodysplastic syndrome with excess blasts.

Thalassaemia in China.

Because of successful thalassaemia prevention programmes in resource-rich countries and it's huge population China now has the greatest number of new cases of thalassaemia globally as well as more people with thalassaemia than any other country. 30 million Chinese have thalassaemia-associated mutations and about 300,000 have thalassaemia major or intermedia requiring medical intervention. Over the past 2 decades there has been tremendous economic growth in China including per capita spending on health care. There is now nation-wide availability and partial or full insurance for prenatal genetic testing, RBC-transfusions, iron-chelating drugs and haematopoietic cell transplants. Prenatal screening and educational programmes have reduced the incidence of new cases. However, substantial challenges remain. For example, regional differences in access to medical care and unequal economic development require innovations to reduce the medical, financial and psychological burdens of Chinese with thalassaemia and their families. In this review we discuss success in preventing and treating thalassaemia in China highlighting remaining challenges. Our discussion has important implications for resource-poor geospaces challenged with preventing and treating thalassaemia.

[Expression Changes of Hypoxia-Inducible Factor-1α in G-CSF Induced Hematopoietic Stem Cell Mobilization].

OBJECTIVE: To investigate the expression and its relative mechanism of hypoxia-inducible factor-1α(HIF-1α) in bone marrow(BM) of mice during G-CSF mobilization of hematopoietic stem cells (HSC) . METHODS: Flow cytometry was used to detect the proportion of Lin-Sca-1+ c-kit+ (LSK) cells in peripheral blood of C57BL/6J mice before and after G-CSF mobilization. And the expression of HIF-1α and osteocalcin (OCN) mRNA and protein were detected by RQ-PCR and immunohistochemistry. The number of osteoblasts in bone marrow specimens of mice was counted under the microscope. RESULTS: The proportion of LSK cells in peripheral blood began to increase at day 4 of G-CSF mobilization, and reached the peak at day 5, which was significantly higher than that of control group (P<0.05). There was no distinct difference in the expression of HIF-1α mRNA between bone marrow nucleated cells and osteoblasts of steady-state mice (P=0.073), while OCN mRNA was mainly expressed in osteoblasts, which was higher than that in bone marrow nucleated cells (P=0.034). After mobilization, the expression level of HIF-1α increased, but OCN decreased, and the number of endosteum osteoblasts decreased. The change of HIF-1α expression was later than that of OCN and was consistent with the proportion of LSK cells in peripheral blood. CONCLUSION: The expression of HIF-1α in bone marrow was increased during the mobilization of HSC mediated by G-CSF, and one of the mechanisms may be related to the peripheral migration of HSC induced by osteoblasts inhibition.

Therapeutic adenine base editing of human hematopoietic stem cells.

In ß-thalassemia, either γ-globin induction to form fetal hemoglobin (α2γ2) or ß-globin repair to restore adult hemoglobin (α2ß2) could be therapeutic. ABE8e, a recently evolved adenine base editor variant, can achieve efficient adenine conversion, yet its application in patient-derived hematopoietic stem cells needs further exploration. Here, we purified ABE8e for ribonucleoprotein electroporation of ß-thalassemia patient CD34+ hematopoietic stem and progenitor cells to introduce nucleotide substitutions that upregulate γ-globin expression in the BCL11A enhancer or in the HBG promoter. We observed highly efficient on-target adenine base edits at these two regulatory regions, resulting in robust γ-globin induction. Moreover, we developed ABE8e-SpRY, a near-PAMless ABE variant, and successfully applied ABE8e-SpRY RNP to directly correct HbE and IVS II-654 mutations in patient-derived CD34+ HSPCs. Finally, durable therapeutic editing was produced in self-renewing repopulating human HSCs as assayed in primary and secondary recipients. Together, these results support the potential of ABE-mediated base editing in HSCs to treat inherited monogenic blood disorders.

Hematopoietic Stem Cell Transplantation Activity in China 2020-2021 During the SARS-CoV-2 Pandemic: A Report From the Chinese Blood and Marrow Transplantation Registry Group.

Between 2020 and 2021, 31,525 hematopoietic stem cell transplantations (HSCTs) were reported to the Chinese Blood and Marrow Transplantation Registry Group throughout mainland China. In this report, we describe the activity and current trends for HSCT in China during the SARS-CoV-2 pandemic. In 2020, a total of 13,415 cases of HSCT were reported from 166 transplantation teams, and 75% (10,042 cases) were allogeneic HSCTs. In 2021, a total of 18,110 cases of HSCT were reported from 174 transplantation teams, and 70% (12,744 cases) were allogeneic HSCTs. Haploidentical donor (HID) transplantation accounted for 63% (7977 cases) of allogeneic HSCTs in 2021. The most common indications for allogeneic HSCT for malignant disease were acute myeloid leukemia (37%) and acute lymphoblastic leukemia (23%), and the largest proportion of nonmalignant disease comprised aplastic anemia (13%). The peripheral blood stem cell source accounted for 41% of HIDs and 75% of matched sibling donors. The BuCy-based regimen (57%) was the most popular conditioning regimen for allogeneic HSCT, followed by the BuFlu-based regimen (28%) and total body irradiation-based regimen (11%). This survey provides comprehensive information about the current activities and might benefit clinical physicians' decision planning for HSCT.

Efficacy, residual effectiveness and safety of diacerein in the treatment of knee osteoarthritis: A meta-analysis of randomized placebo-controlled trials.

BACKGROUND: Osteoarthritis (OA) is the leading cause of disability in the elderly. Prevention and treatment of OA have become an urgent global demand. The pharmacologic role of diacerein in the treatment of osteoarthritis is controversial. We systematically reviewed the efficacy, safety, and residual effectiveness of diacerein. OBJECTIVES: To estimate the symptomatic efficacy, residual effect and safety of diacerein in the treatment of knee osteoarthritis, using a meta-analysis of published randomized controlled trials (RCTs). METHODS: On December 1, 2021, we searched PubMed Medline, Web of Science, Cochrane Library databases, Wan Fang Medical Database, and National Knowledge Infrastructure. This study followed the inclusion criteria of the principle P(Population), I(Intervention), C(Comparison), O(Outcome), S (Study design) principle. All studies were randomized controlled trials of knee osteoarthritis. Cochrane bias risk assessment tool was used to assess the risk of bias. Meta-analyses were performed using a random-effects model. To explore sources of heterogeneity, subgroup analysis, sensitivity analysis, regression analysis and publication bias analysis were performed. Drug side effects with complete data were extracted from the included articles and then a combined analysis of these data was performed. RESULTS: Eight studies were eligible and were included in our analysis (N = 1277 participants). All studies were randomized controlled trials of knee osteoarthritis. There was no significant difference in reduction of joint pain and improvement of function between diacerein and the control group. However, subgroup analysis suggested, compared with the placebo group, diacerein treatment yielded an improved mean reduction in visual analogue scale score of-0.44% (95% confidence interval [CI]-0.79 to 0.09), an improved the western Ontario and McMaster universities (physical function) score of -0.44% (95% CI-0.72 to -0.12). Follow-up analysis after discontinuation showed that diacerein treatment had a significant residual effect (95% CI-0.81 to- 0.24). Data on drug side effects described in the included articles were extracted for statistical analysis. There was an increased risk of diarrhea with diacerein (Risk Ratio [RR] = 1.95 [1.03 to 2.47]) and withdrawal event from therapy (RR = 0.93 [0.75 to 1.15]). CONCLUSION: Diacerein might be considered an effective drug for the treatment of patients with KOA, showing short-term residual effectiveness. Although it is associated with an increased risk of diarrhea, the adverse event is mostly tolerable.

Application of Gene Therapy in Hemophilia.

Gene therapy refers to introducing normal exogenous genes into target cells to correct or compensate for the diseases caused by defective and abnormal genes for the purpose of therapy. It holds out hope of a cure for single-gene genetic diseases such as thalassemia, hemophilia, etc. At present, gene therapy is performed in two ways: introducing exogenous genes, and gene editing. A great number of clinical trials of gene therapy in hemophilia have been carried out using viral vectors to introduce foreign genes into target cells. However, the production of neutralizing antibodies following injection and the inability to prepare viral vectors in large quantities limit their application. Although gene-editing methods like CRISPR avoid the above problems, the potential risks of off-target effects are still unknown. More trials and evidence are needed to elucidate the safety and accuracy of gene therapy. This paper will review the bench and clinical work of gene therapy in hemophilia in recent years, and summarize the challenges and prospects of gene therapy, so as to provide directions for future scientific research in this field.

Predicting the risk of acute kidney injury after hematopoietic stem cell transplantation: development of a new predictive nomogram.

The purpose was to predict the risk of acute kidney injury (AKI) within 100 days after hematopoietic stem cell transplantation (HSCT) in patients with hematologic disease by using a new predictive nomogram. Collect clinical data of patients with hematologic disease undergoing HSCT in our hospital from August 2012 to March 2018. Parameters with non-zero coefficients were selected by the Least Absolute Selection Operator (LASSO). Then these parameters were selected to build a new predictive nomogram model. Receiver operating characteristic (ROC) curve, calibration curve, C-index, and decision curve analysis (DCA) were used for the validation of the evaluation model. Finally, the nomogram was further evaluated by internal verification. According to 2012 Kidney Disease Improving Global Guidelines (KDIGO) diagnostic criteria, among 144 patients, the occurrence of AKI within 100 days after HSCT The rate was 29.2% (42/144). The C-index of the nomogram was 0.842. The C-value calculated by the internal verification was 0.809. The AUC was 0.842, and The DCA range of the predicted nomogram was from 0.01 to 0.71. This article established a high-precision nomogram for the first time for predicting the risk of AKI within 100 days after HSCT in patients with hematologic diseases. The nomogram had good clinical validity and reliability. For clinicians, it was very important to prevent AKI after HSCT.

Health-related quality of life in pediatric patients with ß-thalassemia major after hematopoietic stem cell transplantation.

Our main purpose was to evaluate health-related quality of life (HRQOL) in ß-thalassemia major patients who underwent transplantation from September 2012 to November 2019. The PedsQL 4.0 scale proxy version was administered to 221 transplant patients aged 5-18 years. Their HRQOL results in the proxy-report were compared with those in the proxy-report of 429 matched healthy peers and 198 matched nontransplant patients. Compared with their healthy peers, the transplant patients exhibited worse HRQOL in the physical health domain (P < 0.001), school domain (P < 0.001) and overall scores (P = 0.006). Patients within 4 years after transplantation exhibited physical functioning (P < 0.001), school functioning (P < 0.001) and overall HRQOL damage (P = 0.001); the scores across all domains for patients more than 4 years after transplantation were not significantly different from those for the healthy controls. The transplant patients rated their HRQOL for all domains better than the nontransplant patients (P < 0.001). The HRQOL of patients after human leukocyte antigen (HLA)-matched related and HLA-matched unrelated donor transplantation were not significantly different. Chronic graft-versus-host disease and two or more comorbidities were independently negatively associated with overall HRQOL outcomes (P = 0.032 and P < 0.001, respectively). In conclusion, patients more than 4 years after transplantation achieve an HRQOL equal to that of their healthy peers.

HIF-1α protects osteoblasts from ROS-induced apoptosis.

The regulatory mechanism of hypoxia-inducible factor-1α (HIF-1α) is complex. HIF-1α may inhibit or promote apoptosis in osteoblasts under different physiological conditions, and induce bone regeneration and repair injury in coordination with angiogenesis. The relationship between H2O2 and HIFs is complex, and this study aimed to explore the role of HIF-1α in H2O2-induced apoptosis. Dimethyloxallyl glycine (DMOG) and 2-Methoxyestradiol (2ME) were used to stabilize and inhibit HIFs, respectively. Cell viability was assessed with CCK8. Apoptosis and ROS levels were detected by flow cytometry, and HIF mRNA expression was assessed by reverse transcription-polymerase chain reaction (RT-PCR). Western blot was performed to detect HIF-1α, HIF-2α, Bax, Bak, Bcl-2, Bcl-XL, caspase-9, and PCNA protein amounts. Our data suggest that both HIF-1α and HIF-2α play a protective role in oxidative stress. HIF-1α reduces H2O2-induced apoptosis by upregulating Bcl-2 and Bcl-XL, downregulating Bax, Bak, and caspase-9, stabilizing intracellular ROS levels, and promoting the repair of H2O2-induced DNA damage to reduce apoptosis.

Iron overload status in patients with non-transfusion-dependent thalassemia in China.

Background: Iron overload is one of the main factors that increase morbidity and mortality in patients with non-transfusion dependent thalassemia (NTDT). Aim: This study aimed at investigating the prevalence and severity of iron overload in Chinese NTDT patients. Methods: we analyzed serum ferritin (SF), liver iron concentration (LIC) and cardiac T2* in 178 Chinese NTDT in this cross-sectional study. Results: The median SF level was 996.00(27.15-19704.00) ng/ml and the median LIC value was 8.90(0.60-43.00) mg Fe/g dry weight (dw). The youngest patient with liver iron overload was 5 years old with 5.6 mg Fe/g dw in LIC. The median cardiac T2* was 33.06(7.46-75.08) ms. 6 patients had cardiac T2*⩽20ms. The patients with ß thalassemia intermedia and HbE/ß thalassemia showed a statistically significant lower Hb and higher values of SF and LIC than those of hemoglobin H disease patients. On multivariate logistic regression analysis, patients in ⩾ age 30-year old had a significant higher risk for iron overload (OR: 77.75, 95% CI: 8.76-690.49) in the age group. The detailed analysis of proportions of different LIC indicate in > 30-year old group, 76.8% patients suffered from moderate and severe LIC. Conclusion: Our study provides a strong support for the novel findings that Chinese NTDT patients have a high prevalence of iron overload. The first assessment of MRI LIC should be performed as early as 5 years old. Then, NTDT patients > 30 years old may suffer with a high burden of iron overload.

[Clinical Analysis of Bloodstream Infection after Hematopoietic Stem Cell Transplantation].

OBJECTIVE: To analyze the clinical characteristics of bloodstream infection (BSI) in patients treated by hematopoietic stem cell transplantation (HSCT). METHODS: The clinical characteristics, distribution of pathogenic bacteria causing BSI and drug sensitivity of 910 patients treated by HSCT in our department from January 2013 to June 2020 were retrospectively analyzed. RESULTS: Among 910 HSCT patients, 111 patients were diagnosed as BSI within 100 days after transplantation, and 98 patients showed BSI during the period of agranulocytosis. Multivariate analysis showed that the usage of anti-thymocyte globulin (ATG), long duration of agranulocytosis and low infusion volume of mononuclear cell (MNC) were the independent risk factors affecting BSI after HSCT. Among 121 pathogenic bacteria isolated, 76 Gram-negative (G-) bacteria (62.8%), 40 Gram-positive (G+) bacteria (33.0%), and 5 fungi (4.1%) were detected out. The top three pathogens were Escherichia coli, Staphylococcus epidermidis and Pseudomonas aeruginosa. The drug-resistance rates of Escherichia coli and Klebsiella pneumoniae to carbapenems was 14.3% and 7.7%, respectively, and Pseudomonas aeruginosa was 66.7%. The susceptibility of G+ bacteria to vancomycin, linezolid and teicoplanin was 97.5%, 100% and 100%, respectively. The crude mortality rate of the patients with BSI at 100 days after HSCT was significantly higher than that of patients without BSI (P<0.001). CONCLUSION: The usage of ATG, long duration of agranulocytosis and low infusion volume of MNC are independent risk factors for BSI after HSCT. The pathogens after HSCT are mainly G- bacteria. Pseudomonas aeruginosa is highly resistant to carbapenems. Key words　　;

MiR-197-3p reduces bortezomib resistance in multiple myeloma by inhibiting IL-6 expression in a MEAF6-dependent manner.

OBJECTIVE: This study investigated the mechanism by which miR-197-3p regulated IL-6 expression and reduced bortezomib (BTZ) resistance in multiple myeloma (MM). METHODS: The expression of miR-197-3p, MEAF6 and IL-6 in BTZ-resistant MM cells was measured. The effects of miR-197-3p/IL-6 axis on drug resistance and cell apoptosis were evaluated in BTZ-resistant MM cells. The expression of JAK/STAT3 proteins was detected by Western blotting. The binding of miR-197-3p to MEAF6 mRNA was verified using molecular biology techniques. Chromatin immunoprecipitation was used to assess histone acetylation in IL-6 promoter. The effect of miR-197-3p on MM growth was investigated in a mouse model. RESULTS: MiR-197-3p was lowly expressed, and MEAF6 and IL-6 were highly expressed in BTZ-resistant MM cells. Overexpression of miR-197-3p increased drug sensitivity in BTZ-resistant MM cells, which was counteracted by overexpression of IL-6. Overexpression of miR-197-3p also inhibited MM growth in vivo. Mechanistically, miR-197-3p suppressed the expression of IL-6 by inhibiting MEAF6-mediated histone H3 acetylation in IL-6 promoter. The miR-197-3p/IL-6 axis also inhibited the activation of JAK/STAT3 signaling pathway. CONCLUSION: miR-197-3p reduces BTZ resistance in MM by inhibiting acetylation-mediated expression of IL-6 and by inactivating JAK/STAT3 signaling pathway.