Distinct activities of Vδ1+ T-cells upon different cytomegalovirus reactivation status after haematopoietic transplantation.

Cytomegalovirus (CMV) reactivation is the most frequent viral infectious complication correlating to non-relapse mortality after allogeneic haematopoietic cell transplantation (alloHCT). The intrinsic anti-CMV immunity has not been completely elucidated. γδ T-cells have drawn increasing attentions due to their distinct biological features and potential ability against viral infections. Previous studies reported a general association of γδ T-cells or Vδ2-negative γδ T-cells with CMV reactivation. Whereas researches for the direct responses and specific functions of γδ T subsets remain limited, especially in the scenario of alloHCT. Herein, we initially demonstrated that Vδ1+ T-cells directly and independently recognized cell-free CMV and CMV-infected target cells, and inhibited CMV replication in vitro. The anti-CMV effect of Vδ1+ T-cells was partially through TCRγδ, TLR2 and NKG2D receptor pathways. Further investigation about the anti-CMV characteristics of Vδ1+ T-cells was performed in a clinical cohort with different CMV reactivation status after alloHCT. We found that occasional CMV reactivation remarkably increased the recovery levels and stimulated the functional activity of Vδ1+ T-cells. Whereas disability of Vδ1+ T-cells was observed upon refractory CMV reactivation indicating the differential responses of Vδ1+ T-cells under different CMV reactivation status. CXCL10 and IFN-ß that were dramatically induced by occasional CMV reactivation could re-activate the deficient Vδ1+ T-cells from recipients with refractory CMV reactivation. These findings unveiled the distinct activities of Vδ1+ T-cells in anti-CMV immunity after alloHCT and may help develop novel strategies for the treatment of CMV infectious diseases.

CD277 agonist enhances the immunogenicity of relapsed/refractory acute myeloid leukemia towards Vδ2+ T cell cytotoxicity.

Relapse and refractoriness remain the major obstacles in clinical treatment of acute myeloid leukemia (AML). Efficacy of current therapeutic strategies for relapsed/refractory (R/R) AML is generally unsatisfying. Vδ2+ T cells have become an attractive candidate for immunotherapy of various types of tumors. However, the results were not exciting in some pilot studies utilizing Vδ2 cell-based protocols to treat R/R AML. Functional receptors on Vδ2 cells and immunogenic ligands on leukemia cells are both critical to the anti-AML effect of Vδ2 cells, which have not been characterized in the context of R/R AML. CD277 can bind to phosphoantigens and promote the activation of Vδ2 cells. Anti-CD277 (clone 20.1) monoclonal antibody (20.1 mAb) has been identified as an agonist of CD277. Whether 20.1 mAb sensitizes R/R AML cells awaits investigation. Herein, we showed that the expressions of activating receptors on Vδ2 cells and CD277 on leukemia cells were deficient in patients with R/R AML. While agonists for NKG2D and TRAIL ligands did not increase the immunogenicity of R/R AML cells, 20.1 mAb significantly enhanced the cytotoxicity of Vδ2 cells on the drug-resistant human AML cell line and different types of primary AML cells from R/R patients. The sensitizing effect of 20.1 mAb was dependent on inducing degranulation of Vδ2 cells. These findings suggest a decisive role of CD277 in mediating the recognition of R/R AML cells by Vδ2+ T cells. CD277 agonist combining adoptive transfer of Vδ2+ T cells may improve the efficacy in the treatment of R/R AML.

Wellens' syndrome: incidence, characteristics, and long-term clinical outcomes.

BACKGROUND: Few studies with large sample sizes are available regarding patients with Wellens' syndrome. Therefore, we sought to assess the current incidence, risk factors, clinical presentation and long-term outcomes of this population. METHODS: Among a total of 3528 patients with ACS who underwent angioplasty from 2017 to 2019 in our centre, 2127 NSTE-ACS patients with culprit LAD vessels were enrolled in this study. According to electrocardiographic criteria, the patients were divided into a Wellens' group (n = 200) and non-Wellens' group (n = 1927). The primary endpoint was cardiac death; the secondary endpoint was MACCE, a composite of all-cause death, cardiac death, recurrent myocardial infarction, target lesion revascularization, heart failure and stroke. RESULTS: The incidence of Wellens' syndrome was 5.7% (200 of 3528) of all ACS patients. Wellens' syndrome more often manifested as NSTEMI (69% vs. 17.5%, P < 0.001). The percentages of preexisting coronary heart disease (39.6% vs. 23%) and previous PCI (19.5% vs. 9%) were significantly higher in the non-Wellens' group than in the Wellens' group (all P < 0.001). More importantly, the proportion of early PCI was higher in the Wellens' group (68% vs. 59.3%, P = 0.017). At a median follow-up of 24 months, Wellens' syndrome was not associated with an increased risk of MACCE (P = 0.05) or cardiac death (P = 0.188). CONCLUSIONS: The presence of Wellens' syndrome is not definitively associated with adverse prognosis in patients with NSTE-ACS. Age ≥ 65 years, diabetes, NSTEMI, eGFR < 60 ml/min and left main disease are associated with the incidence of cardiac death. Early recognition and aggressive intervention are critical, as they may help to attenuate adverse outcomes.

Impact of COVID-19 pandemic on STEMI undergoing primary PCI treatment in Beijing, China.

OBJECTIVE: Strict control measures under the COVID epidemic have brought an inevitable impact on ST-segment elevation myocardial infarction (STEMI)'s emergency treatment. We investigated the impact of the COVID on the treatment of patients with STEMI undergoing primary PCI. METHODS: In this single center cohort study, we selected a time frame of 6 month after declaration of COVID-19 infection (Jan 24-July 24, 2020); a group of STEMI patients in the same period of 2019 was used as control. Finally, a total of 246 STEMI patients, who were underwent primary PCI, were enrolled into the study (136 non COVID-19 outbreak periods and 110 COVID-19 outbreak periods). The impact of COVID on the time of symptom onset to the first medical contact (symptom-to-FMC) and door to balloon (D-to-B) was investigated. Moreover, the primary outcome was in-hospital major adverse cardiac events (MACE), defined as a composite of cardiac death, heart failure and malignant arrhythmia. RESULTS: Compared with the same period in 2019, there was a 19% decrease in the total number of STEMI patients undergoing primary PCI at the peak of the pandemic in 2020. The delay in symptom-to-FMC was significantly longer in COVID Outbreak period (180 [68.75, 342] vs 120 [60,240] min, P = 0.003), and the D-to-B times increased significantly (148 [115-190] vs 84 [70-120] min, P < 0.001). However, among patients with STEMI, MACE was similar in both time periods (18.3% vs 25.7%, p = 0.168). On multivariable analysis, COVID was not independently associated with MACE; the history of diabetes, left main disease and age>65 years were the strongest predictors of MACE in the overall population. CONCLUSIONS: The COVID pandemic was not independently associated with MACE; suggesting that active primary PCI treatment preserved high-quality standards even when challenged by a severe epidemic. CLINICAL TRIAL REGISTRATION: URL: https://ClinicalTrials.gov Unique identifier: NCT04427735.

Point-of-care DNA testing by automatically and sequentially performing extraction, amplification and identification in a closed-type cassette.

Nucleic acid detection is important for clinical diagnostics; however, it is challenging to perform genetic testing at the point-of-care due to the tedious steps involved in DNA extraction and the risk of cross-contamination from amplicons. To achieve a fully-automated and contamination-free nucleic acid detection, we propose a closed-type cassette system which enables the following steps to be operated automatically and sequentially: sample preparation based on magnetic beads, target amplification using multiplex polymerase chain reaction, and colorimetric detection of amplicons using a serial invasive reaction coupled with the aggregation of gold nanoparticle probes. The cassette was designed to be round and closed, and 10 targets in a sample could be simultaneously detected by the naked eye or using a spectrophotometer in the system. In addition, a cassette-driven device was fabricated to transfer reagents between wells, to control the temperature of each reaction, and to sense the colour in the detection wells. The cassette system was sensitive enough to detect 10 genotypes at 5 single nucleotide polymorphism sites related to the anticoagulant's usage, by using a 0.5 µL blood sample. The accuracy of the system was evaluated by detecting 12 whole blood samples, and the results obtained were consistent with those obtained using pyrosequencing. The cassette is airtight and the whole system is fully automatic; the only manual operation is the addition of the sample to the cassette, performing point-of-care genetic testing in a sample-in/answer-out way.

STAT5 is essential for inducing the suppressive subset and attenuate cytotoxicity of Vδ2+ T cells in acute myeloid leukemia.

Under the sustained exposure to tumor microenvironment, effector lymphocytes may transform into the suppressive populations. γδ T cells are recognized as a crucial mediator and effector of immune surveillance and thereby a promising candidate for anti-tumor immunotherapy. Emerging clinical studies implicate that some γδ T subsets play an important role in promoting tumor progression. Our previous study identified an abnormal Vδ2+ T cells subset with regulatory features (Reg-Vδ2) in the patients with newly diagnosed acute myeloid leukemia (AML), and demonstrated that Reg-Vδ2 cells significantly suppressed the anti-AML effects of effector Vδ2 cells (Eff-Vδ2). The molecular mechanism underlying the subset transformation of Vδ2 cells remains unclear. Here, we found that the expression and activity of STAT5 were significantly induced in Reg-Vδ2 cells compared with Eff-Vδ2 cells, which was consistent with the differences found in primary Vδ2 cells between AML patients and healthy donors. In-vitro experiments further indicated that STAT5 was required for the induction of Reg-Vδ2 cells. The combined immunophenotypical and functional assays showed that blockage of STAT5 alleviated the immunosuppressive effect of Reg-Vδ2 cells on Eff-Vδ2 cells and enhanced the anti-AML capacity of Vδ2 cells from health donors and AML patients. Collectively, these results suggest that STAT5 acts as a critical regulator in the transformation of effector Vδ2 cells into a subset with immunosuppressive characteristics, providing a potential target for the improvement the efficacy of γδ T cells-based immunotherapy to treat AML and other hematologic malignancies.

Exploring the Predictors of the Discrepancy Between Quantitative Flow Ratio and Fractional Flow Reserve Measurements.

BACKGROUND: Quantitative flow ratio is a novel technology for the functional assessment of intermediate coronary stenoses. The authors sought to explore the influence of diabetes mellitus on the application of quantitative flow ratio and predictors of discrepancies between quantitative flow ratio and fractional flow reserve. METHODS: Quantitative flow ratio was calculated in 224 patients (317 vessels) who underwent fractional flow reserve measurement by professional technicians blinded to fractional flow reserve value. Patients were divided into the diabetes mellitus group and the non-diabetes mellitus group. The diagnostic performance of quantitative flow ratio was assessed using fractional flow reserve as a reference. RESULTS: Good correlation and agreement between quantitative flow ratio and fractional flow reserve can be found in the diabetes mellitus group (r = 0.834, P <.001; mean difference: 0.007 ± 0.108). Prior myocardial infarction showed a statistically significant association with increased classification discrepancy between quantitative flow ratio and fractional flow reserve (odds ratio 3.16 (95% confidence interval: 1.29-7.75), P =.01). The area under the receiver-operating characteristic curve of quantitative flow ratio showed no significant difference in diabetes mellitus and non-diabetes mellitus groups, hemoglobin A1c ≥ 7% and hemoglobin A1c < 7% groups, diabetic duration ≥ 10 years and diabetic duration < 10 years groups (area under receiver-operating characteristic curve: 0.90 (95% confidence interval: 0.84-0.94) vs. 0.92 (95% confidence interval: 0.87-0.96), P =.54; 0.89 (95% confidence interval: 0.81-0.95) vs. 0.92 (95% confidence interval: 0.81-0.97), P =.65; 0.88 (95% confidence interval: 0.79-0.94) vs. 0.89 (95% confidence interval: 0.79-0.96), P =.83; respectively). CONCLUSIONS: Clinical application of quantitative flow ratio is not limited to diabetic patients. The relationship between prior myocardial infarction and quantitative flow ratio needs to be further developed.

Characteristics of Wellens' Syndrome in the Current PCI Era: A Single-Center Retrospective Study.

Objectives: The goal of this retrospective study was to reveal the prevalence, angiographic characteristics, clinical presentation, and long-term outcomes of non-ST-segment elevation myocardial infarction (NSTEMI) patients with Wellens' syndrome. Background: Procedural results for percutaneous coronary intervention (PCI) in acute coronary syndrome (ACS) have improved in recent years. However, there is still a paucity of available clinical trial data for Wellens' syndrome even though it is a well-known high-risk ACS. Methods: Among a total of 3528 patients with ACS who underwent angioplasty from 2017 to 2019 at the Cardiovascular Center of Beijing Friendship Hospital, 476 NSTEMI patients with culprit left anterior descending (LAD) vessels were enrolled in this study. According to electrocardiographic criteria of Wellens' syndrome, the patients were divided into a Wellens group (n = 138) and a non-Wellens group (n = 338). The primary endpoint was cardiac death; the secondary endpoints were main adverse cardiovascular and cerebrovascular events (MACCEs), a composite of all-cause death, cardiac death, heart failure, target lesion revascularization, recurrent myocardial infarction, and stroke. All of the medical and follow-up data were obtained from our institutional database. Results: The incidence of Wellens' syndrome in all ACS patients was 5.7% (200 of 3528). Among the 200 patients with Wellens' syndrome, 138 had NSTEMI, for a proportion of 69%. There was a significant decrease in the percentage of preexisting coronary heart disease (CHD), prior myocardial infarction, and previous PCI (P < 0.05) in the Wellens group compared with the non-Wellens group. On coronary angiography, single-vessel lesions were more common in the Wellens group (11.6% vs. 5.3%, P=0.016), and almost all (97.1%) of these patients received drug-eluting stents. Notably, the Wellens group had a higher proportion of early PCI than the non-Wellens group (71% vs. 61.2%, P=0.044). At 24 months, there was no statistically significant difference in cardiac death (P=0.111) between the two groups, but the MACCEs were comparable (Wellens: 5.1% vs. non-Wellens: 13.3%, P=0.009). Age ≥65 years was the largest independent risk factor for adverse prognosis. Conclusions: With early recognition and aggressive intervention, Wellens' syndrome is no longer a risk factor for adverse prognosis in patients with NSTEMI in the current PCI era.

Identification of the immunosuppressive effect of γδ T cells correlated to bone morphogenetic protein 2 in acute myeloid leukemia.

Description of immune landscapes in malignant microenvironment is critical to the improvement of therapeutic strategies for various tumors. Acute myeloid leukemia (AML) remains a severe life-threatening malignancy and often confronts treatment dilemma in clinic. Although γδ T cells exhibit independent and potent cytotoxicity against leukemic cells in vitro and in the mouse models, efficacy of γδ T cell-based immunotherapy on AML patients has seemed unsatisfying so far. How the anti-AML capacity of γδ T cells is suppressed in vivo remains elusive. Herein, we found an aberrant γδ T cells subset expressing CD25+CD127lowVδ2+ in the bone marrows of patients with newly diagnosed AML. The emergence of this subset was significantly associated with disease status and risk stratification as well as with the abnormally increased bone morphogenetic protein 2 (BMP2). Mechanistically, BMP2 could directly induce CD25+CD127lowVδ2+ γδ T cells (named as Reg-Vδ2) in vitro. The immunosuppressive features of Reg-Vδ2 cells were identified by combining immunophenotypical and functional data. Furthermore, inhibition of BMP2 pathway significantly blocked the emergence of Reg-Vδ2 cells and enhanced the anti-AML immunity in humanized mice. These findings not only provide a novel insight into the mechanisms of immunosuppression in the context of leukemia, but also suggest potential targets for the treatment of AML and other hematopoietic malignancies.

Insight into the vacancy effects on mechanical and electronic properties of V5Si3 silicides from first-principles calculations.

As so far, the development and application prospects of transition metal silicon-based materials have received the considerable attention. V-Si silicides are one of the most important silicon-based high-temperature materials. Brittle behavior hinders their wide application. In present work, the influence of vackancies on mechanical properties, brittle/ductile behavior and electronic properties of V5Si3 silicides is studied using the first-principles calculations. The vacancy formation energy, elastic constants, elastic modulus, brittle/ductile behavior and electronic behavior of the perfect V5Si3 and V5Si3 with vacancies were comparatively calculated and discussed, respectively. The thermodynamic data and phonon frequencies demonstrate that the V5Si3 with different vacancies can exhibit the structural stability. Although the vacancies weaken the hardness of V5Si3, the vacancies improve the brittle behavior of the parent V5Si3. Especially, the Si-Va1 and Si-Va2 vacancies in V5Si3 induced brittle-to-ductile transition for V5Si3 desilicides. The electronic structures explain the mechanism of the difference of mechanical properties for different vacancies.

A first principles investigation on the influence of transition-metal elements on the structural, mechanical, and anisotropic properties of CaM2Al20 intermetallics.

The anisotropy in elasticity, mechanical properties and electronic properties of CaM2Al20 (M = V, Nb, Cr, Ti, Mo and Ta) compounds were investigated using the first-principle calculations. These ternary compounds are structurally stable according to the obtained phonon frequencies and formation enthalpy. The results of elastic modulus, hardness and elastic constants explain that CaM2Al20 intermetallics have higher hardness and better resistance to deformation change than pure aluminum. Poisson's ratio and the values of B/G confirm that CaTi2Al20, CaV2Al20, CaCr2Al20, CaNb2Al20 and CaTa2Al20 are brittle materials, but CaMo2Al20 is ductile material. The 3D surfaces of Young's modulus and anisotropic constants confirm that CaMo2Al20 and CaTi2Al20 have the larger anisotropy than other four compounds. What's more, the density of states and charge density differences of CaM2Al20 compounds explain the mechanism of the structural stability and mechanical properties.

Visualized detection of single-base difference in multiplexed loop-mediated isothermal amplification amplicons by invasive reaction coupled with oligonucleotide probe-modified gold nanoparticles.

Loop-mediated isothermal amplification (LAMP) is a well-developed DNA amplification method with an ultra-high sensitivity, but it is difficult to recognize a single-base difference (like genotyping) in target-specific amplicons by conventional detection ways, such as the intercalation of dyes into dsDNA amplicons or the increase of solution turbidity along with the polymerization process. To allow genotyping based on LAMP suitable for POCT (point-of-care testing) or on-site testing, here we proposed a highly specific and cost-effective method for detecting a single-base difference in LAMP amplicons. The method includes three key steps, sequence amplifier to amplify multiple fragments containing the single nucleotide polymorphisms (SNPs) of interest, allele identifier to recognize a targeted base in the amplicons by invasive reaction, and signal generator to yield signals by hybridization-induced assembly of oligonucleotide probe-modified gold nanoparticles. Because the allele identifier is sensitive to one base difference, it is possible to use multiplexed LAMP (mLAMP) to generate amplicon mixtures for multiple SNP typing. Genotyping of 3 different SNPs (CYP2C19*2, CYP2C19*3 and MDR1-C3435T) for guiding the dosage of clopidogrel is successfully carried out in a 3-plex LAMP on real clinical samples. As our method relies on the naked-eye detection and constant-temperature reaction, no expensive instrument is required for both target amplification and sequence identification, thus much suitable for inexpensive gene-guided personalized medicine in source-limited regions.

A universal genotyping-microarray constructed by ligating a universal fluorescence-probe with SNP-encoded flaps cleaved from multiplex invasive reactions.

To achieve a microarray universal to any SNP, we proposed a new way to construct a genotyping-microarray by ligating a universal fluorescence-probe with SNP-encoded flaps cleaved from invasive reactions on a slide surface. Our proposed microarray is labor-saving and cost-saving in setting up a new experiment for genotyping multiple SNPs, which is related to personalized medicine.