Clinical Manifestation, Risk Factors, and Immune Checkpoint Inhibitor Rechallenge of Checkpoint Inhibitor-Associated Pneumonitis in Patients With Lung Cancer.

SUMMARY: Immune-related adverse effects can lead to damage to various systems of the body, checkpoint inhibitor-associated pneumonitis (CIP) is one of the potentially lethal immune-related adverse effects. However, evidence regarding the risk factors associated with CIP is limited. To timely and accurate identification and prompt treatment of CIP, understanding the risk factors for multimorbidity among diverse study populations becomes crucial. We retrospectively analyzed the clinical data of 1131 patients with lung cancer receiving immunotherapy to identify 110 patients with CIP, the clinical characteristics and radiographic features of patients with CIP were analyzed. A case-control study was subsequently performed to identify the risk factors of CIP. The median treatment cycle was 5 cycles and the median time to onset of CIP was 4.2 months. CIP was mainly grade I or II. Most cases improved after discontinuation of immune checkpoint inhibitors (ICIs) or hormone therapy. Severe CIP tended to occur earlier in comparison to mild to moderate cases. The recurrence rate was 20.6% in ICI-rechallenged patients, and patients with relapsed CIP were usually accompanied by higher-grade adverse events than at first onset. Among the 7 patients with relapse, ICI-associated deaths occurred in 2 patients (28.6%). For rechallenging with ICIs after recovery from CIP, caution should be practiced. Male [odds ratio (OR): 2.067; 95% CI: 1.194-3.579; P= 0.009], history of chest radiation (OR: 1.642; 95% CI: 1.002-2.689; P= 0.049) and underlying lung disease (OR: 2.347; 95% CI: 1.008-5.464; P=0.048) was associated with a higher risk of CIP.

Blockage of CD72 reduces B cell proliferation in immune thrombocytopenic purpura, involving interleukin 1 and macrophage migration inhibitory factor secretion.

AIM: This study aims to explore the expression and role of CD72 in B lymphocytes in immune thrombocytopenic purpura (ITP). METHODS: The expression level of CD72 in B lymphocytes was detected by flow cytometry in 18 ITP patients and 19 controls of healthy donor or iron-deficiency anemia patients. B cell proliferation was determined by 5-bromo-2'-deoxyuridine incorporation (BrdU) in the culture of 17 ITP patients' and 11 controls' peripheral mononuclear cells (PMNCs). The secretion levels of antibodies against human platelet antigens (HPA), as well as B cell proliferation-related cytokine interleukin 1(IL-1) and macrophage migration inhibitory factor (MIF) in culture supernatants were measured by ELISA. RESULTS: CD72 was significantly increased in B cells of newly diagnosed or persistent ITP compared with ITP in remission. B cell proliferation in culture with CD72 antibody addition was significantly decreased both in ITP patients and in controls compared with isotype antibody addition. CD72 antibody did not significantly alter HPA antibody level in ITP patients. CD72 antibody increased IL-1 and MIF levels in ITP patients' cell culture supernatant but not in controls. CONCLUSION: CD72 expression elevation accompanies the active status of ITP. In vitro addition of CD72 antibody has a negative impact on B cell proliferation. The function of CD72 in B cell proliferation in ITP may be related to IL-1 and MIF secretion.

[Efficacy and Safety of Cladribine-based Intensified Conditioning Regimen in Hematopoietic Stem Cell Transplantation in Patients with High-Risk Acute Myeloid Leukemia].

OBJECTIVE: To investigate the efficacy, safety and the risk factors affecting prognosis of high-risk acute myeloid leukemia (AML) patients treated by cladribine-based intensified conditioning regimen. METHODS: The clinical data of 28 patients with high-risk AML treated by cladribine in combination with busulfan plus cyclophosphamide (BuCy) intensified conditioning regimen before allogeneic hematopoietic stem cell transplantation (allo-HSCT) in Zhujiang Hospital, Southern Medical University from October 2016 to June 2020 were analyzed retrospectively. The overall survival (OS) rate, cumulative progression-free survival (PFS) rate, relapse rate, non-relapse mortality (NRM), regimen related toxicity (RRT) and risk factors affecting prognosis of the patients were analyzed. RESULTS: The 1-year OS and PFS of the patients after implantation was (78.8±8.6)% and (79.8±8.1)%, while the 1-year cumulative relapse rate and NRM of the patients was 9.3% and 22.0%, respectively. The 1-year expected OS of MRD- high-risk patients before HSCT was 100%. The 1-year expected OS and PFS of the patients in pre-transplant relapse group was (46.9±18.7)% and (50.0±17.7)%, respectively. The incidence of I/II grade RRT was 39.3%. NO III/IV grade RRT were found in 28 patients. Multivariate analysis showed that pre-transplant relapse was the independent risk factor affecting OS and PFS of the patients. CONCLUSION: The intensified conditioning regimen of cladribine in combination with BuCy can reduce the relapse rate of high-risk AML transplantation, and its RRT is mild, exhibiting good safety. MRD- high-risk patients before HSCT can achieve better transplant benefits, but the prognosis of patients with relapse before transplantation is not significantly improved. Therefore, for non-relapsed high-risk AML patients, this intensified conditioning regimen deserves to be considered.

Neutrophil extracellular traps induced by pro-inflammatory cytokines enhance procoagulant activity in NASH patients.

BACKGROUND: Nonalcoholic steatohepatitis (NASH) patients are at a high risk of developing venous thromboembolism, with a high rate of morbidity and mortality. The role of neutrophil extracellular traps (NETs) in procoagulant activity (PCA) in patients with NASH remains unclear. Our study aimed to investigate the formation of NETs in NASH patients stimulated by specific pro-inflammatory factors. Moreover, we evaluated the pivotal role of NETs in the induction of hypercoagulability in NASH and the interaction between NETs and endothelial injury. METHOD: The levels of the NETs biomarkers were evaluated in the plasma samples of 27 NASH patients and 18 healthy subjects. The formation of NETs was visualized using immunofluorescence microscopy. The PCA of the NETs was assessed using coagulation time, purified coagulation complex, and fibrin formation assays. Confocal microscopy was further used to evaluate the interactions between the NETs and HUVECs. RESULTS: The levels of NETs markers in the plasma of NASH patients were significantly higher than healthy controls. NETs derived from NASH enhanced thrombin and fibrin formation and significantly reduced CT (p<0.05). The mixture of IL-6 and TNF-α triggered the NETs release in the plasma rather than them alone. Additionally, the NETs exerted cytotoxic effects on the endothelial cells, converting them to a procoagulant and pro-inflammatory phenotype, and DNase I could reverse these effects. CONCLUSION: Our results revealed the primary role of NETs in promoting the hypercoagulable state in NASH patients. Methods that prevent the formation of NETs may be a novel approach for the prevention and treatment of NASH.

Microvesicles, blood cells, and endothelial cells mediate phosphatidylserine-related prothrombotic state in patients with periodontitis.

BACKGROUND: Phosphatidylserine (PS) is essential for inflammation-associated thrombogenesis, but the exact effect of PS on the prothrombotic state in periodontitis is uncertain. This study aimed to determine the PS-related procoagulant state in patients with periodontitis. METHODS: A total of 138 patients with periodontitis were examined compared with 42 healthy controls. PS-exposing cells and microvesicles in blood samples were detected by confocal microscopy and flow cytometry. The clotting time assay and prothrombinase complex formation assay were used to measure the procoagulant activity of microvesicles, blood cells and endothelial cells. Periodontal clinical parameters and laboratory characteristics of patients with severe periodontitis were recorded and analyzed at baseline and 6 months after non-surgical periodontal therapy. RESULTS: Total PS-positive (PS+ ) microvesicles and the percentage of PS+ blood cells increased in patients with severe periodontitis compared with patients with moderate/mild periodontitis or healthy controls. Endothelial cells cultured in serum from patients with severe periodontitis expressed more PS compared with those cultured in serum from healthy controls. Specifically, PS exposure on blood cells and endothelial cells significantly decreased after inhibiting the effect of inflammatory cytokines. The elevated levels of PS+ cells and microvesicles in severe periodontitis shortened clotting time and led to increased prothrombinase complex formation. Non-surgical periodontal therapy significantly attenuated the release of microvesicles and the PS exposure of blood cells in severe periodontitis. CONCLUSIONS: The prothrombotic state of patients with periodontitis is mediated by PS+ cells and microvesicles stimulated by elevated levels of inflammatory cytokines.

Ruxolitinib for Treatment of Steroid-Refractory Graft-versus-Host Disease: Real-World Data from Chinese Patients.

BACKGROUND: Graft-versus-host disease (GVHD) is a main complication following allogeneic hematopoietic stem cell transplantation and is a leading cause of non-relapse-related death. Unsatisfactory response to standard first-line therapy with glucocorticoids is a predictor of a poor prognosis in patients with GVHD. Ruxolitinib is a selective Janus kinases 1/2 inhibitor which has been shown to control acute (a) and chronic (c) GVHD while maintaining graft-versus-tumor effects. OBJECTIVE: This study aims to evaluate the efficacy and safety of ruxolitinib in the treatment of steroid-refractory GVHD (SR-GVHD) in a population of Chinese patients. METHODS: We report the results of 55 patients, including 23 patients with aGVHD and 32 patients with cGVHD, who were treated with ruxolitinib as salvage therapy between August, 2017 and December, 2020. RESULTS: In patients with aGVHD, the overall response rate (ORR) was 86.9%, and the 1-year overall survival (OS) was 82.6% (95% CI, 67.1-98.1%). The 1-year OS was significantly improved in responders than in non-responders (90.0% vs 33.3%, P=0.004). In patients with cGVHD, the ORR was 78.1%, and the 1-year OS was 81.3% (95% CI, 67.8-94.8%). There was no significant difference in the 1-year OS between responders and non-responders (84.0% vs 71.4%, P=0.327). Cytopenia, cytomegalovirus-reactivation and infections were common adverse events, particularly in patients with aGVHD. CONCLUSION: Our real-world data from Chinese patients further confirm that ruxolitinib is a safe and effective treatment for SR-GVHD.

Immunotherapy for Tumor Metastasis by Artificial Antigen-Presenting Cells via Targeted Microenvironment Regulation and T-Cell Activation.

Effective expansion of T-cells without ex vivo stimulation and maintenance of their antitumor functions in the complex tumor microenvironment (TME) are still daunting challenges in T-cell-based immunotherapy. Here, we developed biomimetic artificial antigen-presenting cells (aAPCs), ultrathin MnOx nanoparticles (NPs) functionalized with T-cell activators (anti-CD3/CD28 mAbs, CD), and tumor cell membranes (CMs) for enhanced lung metastasis immunotherapy. The aAPCs, termed CD-MnOx@CM, not only efficiently enhanced the expansion and activation of intratumoral CD8+ cytotoxic T-cells and dendritic cells after homing to homotypic metastatic tumors but also regulated the TME to facilitate T-cell survival through catalyzing the decomposition of intratumoral H2O2 into O2. Consequently, the aAPCs significantly inhibited the development of lung metastatic nodules and extended the survival of a B16-F10 melanoma metastasis model, while minimizing adverse events. Our work represents a new biomaterial strategy of inhibiting tumor metastasis through targeted TME regulation and in situ T-cell-based immunotherapy.

Neutrophil extracellular traps (NETs): the role of inflammation and coagulation in COVID-19.

COVID-19 has swept quickly across the world with a worrisome death toll. SARS-CoV-2 infection induces cytokine storm, acute respiratory distress syndrome with progressive lung damage, multiple organ failure, and even death. In this review, we summarize the pathophysiologic mechanism of neutrophil extracellular traps (NETs) and hypoxia in three main phases, focused on lung inflammation and thrombosis. Furthermore, microparticle storm resulted from apoptotic blood cells are central contributors to the generation and propagation of thrombosis. We focus on microthrombi in the early stage and describe in detail combined antithrombotic with fibrinolytic therapies to suppress microthrombi evolving into clinical events of thrombosis. We further discuss pulmonary hypertension causing plasmin, fibrinogen and albumin, globulin extruding into alveolar lumens, which impedes gas exchange and induces severe hypoxia. Hypoxia in turn induces pulmonary hypertension, and amplifies ECs damage in this pathophysiologic process, which forms a positive feedback loop, aggravating disease progression. Understanding the mechanisms paves the way for current treatment of COVID-19 patients.

Neutrophil extracellular traps contribute to tissue plasminogen activator resistance in acute ischemic stroke.

Circulating neutrophil extracellular traps (NETs) resistant to t-PA have not been studied completely although NETs in thrombi may contribute to tissue plasminogen activator (t-PA) resistance. This research intended to elucidate whether circulating NETs are associated with t-PA resistance and the underlying mechanism. The levels of NETs were detected in the circulating neutrophils, ischemic brain tissue of acute ischemic stroke (AIS) patients, and transient middle cerebral artery occlusion (tMCAO) models. NET formation in blood, thrombi, and ischemic brain tissue of mice were analyzed by immunofluorescence. Exposed phosphatidylserine (PS) was assessed using flow cytometry and confocal microscopy. Procoagulant activity (PCA) was evaluated using fibrin formation assays, thrombin, and purified coagulation complex. The plasma levels of NETs in AIS patients were significantly higher than those in healthy individuals. After thrombolysis, a significant increase was noted in NET markers in no-improvement patients, while the changes in improvement patients were not significant. Importantly, NETs were decorated with von Willebrand factor (vWF) and plasminogen activator inhibitor-1 (PAI-1) in the blood and thrombi, which could reverse the fibrinolytic effects. In addition, NETs activated platelets (PLTs) and endothelial cells (ECs), stimulating a procoagulant phenotype and facilitating vWF and PAI-1 release. DNase I, activated protein C (APC), and sivelestat markedly inhibited these effects. Furthermore, targeting NETs protected mice from tMCAO-induced cerebral ischemia, possibly by regulating vWF and PAI-1. In summary, NETs may contribute to t-PA resistance in AIS through activation of PLTs and ECs. Strategies against NETs may present a promising therapeutic approach to improve the thrombolysis efficiency of t-PA in AIS patients.

Phosphatidylserine-exposing tumor-derived microparticles exacerbate coagulation and cancer cell transendothelial migration in triple-negative breast cancer.

Background: Neoadjuvant chemotherapy is relevant to the formation of thromboembolism and secondary neoplasms in triple-negative breast cancer (TNBC). Chemotherapy-induced breast cancer cell-derived microparticles (BCMPs) may have important thrombogenic and pro-metastatic effects on platelets and endothelium, which may be related to the expression and distribution of phosphatidylserine (PS). However, investigating these interactions is challenging due to technical limitations. Methods: A study was conducted in 20 healthy individuals and 18 patients who had been recently diagnosed with TNBC and were undergoing neoadjuvant chemotherapy with doxorubicin and cyclophosphamide. BCMPs were isolated from patient blood samples and doxorubicin-treated breast cancer cell lines. Their structure and morphology were studied by electron microscopy and antigen levels were measured by fluorescence-activated cell sorting. In an inhibition assay, isolated BCMPs were pretreated with lactadherin or tissue factor antibodies. Platelets isolated from healthy subjects were treated with BCMPs and coagulation time, fibrin formation, and expression of intrinsic/extrinsic factor Xase (FXa) and thrombin were evaluated. The effects of BCMPs on endothelial thrombogenicity and integrity were assessed by confocal microscopy, electron microscopy, measurement of intrinsic/extrinsic FXa, prothrombinase assay, and transwell permeability assay. Results: Neoadjuvant chemotherapy significantly increased the expression of PS+ BCMPs in patient plasma. Its expression was associated with a rapid increase in procoagulant activity. Treatment with lactadherin, a PS-binding scavenging molecule, markedly reduced the adhesion of BCMPs and abolished their procoagulant activity, but this was not observed with tissue factor antibody treatment. Intravenous injection of BCMPs in mice induced a significant hypercoagulable state, reducing the extent of plasma fibrinogen and promoting the appearance of new thrombus. Cancer cells incubated with doxorubicin released large numbers of PS+ BCMPs, which stimulated and transformed endothelial cells into a procoagulant phenotype and increased the aggregation and activation of platelets. Moreover, cancer cells exploited this BCMP-induced endothelial leakiness and showed promoted metastasis. Pretreatment with lactadherin increased uptake of both PS+ BCMPs and cancer cells by endothelial cells and limited the transendothelial migration of cancer cells. Conclusion: Lactadherin, a biosensor that we developed, was used to study the extracellular vesicle distribution of PS, which revealed a novel PS+ BCMPs administrative axis that initiated a local coagulation cascade and facilitated metastatic colonization of circulating cancer cells.

Aha1 Exhibits Distinctive Dynamics Behavior and Chaperone-Like Activity.

Aha1 is the only co-chaperone known to strongly stimulate the ATPase activity of Hsp90. Meanwhile, besides the well-studied co-chaperone function, human Aha1 has also been demonstrated to exhibit chaperoning activity against stress-denatured proteins. To provide structural insights for a better understanding of Aha1's co-chaperone and chaperone-like activities, nuclear magnetic resonance (NMR) techniques were used to reveal the unique structure and internal dynamics features of full-length human Aha1. We then found that, in solution, both the two domains of Aha1 presented distinctive thermal stabilities and dynamics behaviors defined by their primary sequences and three-dimensional structures. The low thermal stability (melting temperature of Aha128-162: 54.45 °C) and the internal dynamics featured with slow motions on the µs-ms time scale were detected for Aha1's N-terminal domain (Aha1N). The aforementioned experimental results suggest that Aha1N is in an energy-unfavorable state, which would therefore thermostatically favor the interaction of Aha1N with its partner proteins such as Hsp90's middle domain. Differently from Aha1N, Aha1C (Aha1's C-terminal domain) exhibited enhanced thermal stability (melting temperature of Aha1204-335: 72.41 °C) and the internal dynamics featured with intermediate motions on the ps-ns time scale. Aha1C's thermal and structural stabilities make it competent for the stabilization of the exposed hydrophobic groove of dimerized Hsp90's N-terminal domain. Of note, according to the NMR data and the thermal shift results, although the very N-terminal region (M1-W27) and the C-terminal relaxin-like factor (RLF) motif showed no tight contacts with the remaining parts of human Aha1, they were identified to play important roles in the recognition of intrinsically disordered pathological α-synuclein.

Analysis and Clinical Characteristics of 23 Cases of Bone Marrow Necrosis.

BACKGROUND: Bone marrow necrosis (BMN) is a rare secondary disorder of many discrepant neoplastic processes. The etiology is diverse, and malignancy is the most common background disease. PATIENTS AND METHODS: Between 2005 and 2019, a total of 23 cases of BMN were detected and analyzed at Zhujiang Hospital and Nanfang Hospital. RESULTS: In our study, the 40-60-year-old age group was the one with the highest incidence of BMN (n = 12, 52.2%). The background diseases of patients with BMN varied. Eighteen (78.3%) of 23 patients were diagnosed with hematologic diseases at the same time, most of which were acute B lymphocytic leukemia (n = 8, 34.8%). The complete blood count of these 23 patients noted a decrease in hemoglobin (100%), a decrease or increase in white blood cells and neutrophils, and thrombocytopenia (78.3%). The levels of lactate dehydrogenase (> 300 U/L) and serum ferritin (> 500 µg/L) were elevated in all patients, and 16 (94.1%) of 17 patients presented with increased d-dimer levels. The 2-week cumulative survival and 2-year cumulative survival of patients with BMN were 56.5% and 47.4%, respectively. The mortality probability within 2 weeks was 43.5%, and the adjusted mortality probability was 26.7% within 2 weeks to 2 years, indicating that patients with BMN had the greatest risk of death within 2 weeks. CONCLUSION: BMN patients with B lymphocytic leukemia as the background disease had a better prognosis than those with other background diseases. BMN of unknown etiology may have an extremely poor prognosis. Therefore, diagnosing the background disease plays an important role in the treatment of BMN.

Validation of choroidal anastomosis on high-resolution magnetic resonance imaging as an imaging biomarker in hemorrhagic moyamoya disease.

OBJECTIVES: This study aimed to investigate the association between dilation and proliferation and anastomosis of perforating arteries, and intracranial hemorrhage in moyamoya disease (MMD) patients, using high-resolution magnetic resonance imaging (HRMRI). METHODS: Adult patients with MMD at advanced stages were prospectively enrolled and underwent HRMRI exams. Dilation and proliferation of the lenticulostriate artery (LSA), medullary artery, and anterior or posterior choroidal arteries (AChA or PChA) were assessed. Abnormal anastomoses were identified between (1) the LSA and the medullary or insular arteries; (2) the thalamo-geniculate, thalamo-tuberal, or thalamo-perforating arteries and the medullary or insular arteries; and (3) the AChA or PChA and the medullary or insular arteries. The association between these variables and hemorrhagic events was calculated using univariate and multivariate analyses. RESULTS: Fifty patients (14 men; mean age, 35.4 ± 9.7 years) were finally analyzed, including 17 hemorrhagic patients and 33 non-hemorrhagic patients. The inter-rater agreement for the qualitative evaluation of perforating arteries was good. Dilation and proliferation of the AChA or PChA (88.2% versus 54.5%, p = 0.027), and choroidal anastomosis (64.7% versus 18.2%, p = 0.002) were more frequently observed in patients with hemorrhage. Multivariate logistic regression showed that choroidal anastomosis remained significantly associated with hemorrhage (odds ratio = 5.95, 95% confidence interval = 1.21-29.25, p = 0.028). CONCLUSIONS: Choroidal anastomosis is independently associated with hemorrhagic events in adult patients with MMD at advanced stages. HRMRI can provide detailed information on both the anatomies and abnormal collaterals in MMD, which facilitates risk estimates of bleeding in MMD. KEY POINTS: • High-resolution magnetic resonance imaging allows for the evaluation of perforating arteries in patients with moyamoya disease. • Choroidal anastomosis is associated with hemorrhagic events in patients with moyamoya disease. • High-resolution magnetic resonance imaging might facilitate further grading and classification of moyamoya vessels.

Phase I Trial of Fourth-Generation Anti-CD19 Chimeric Antigen Receptor T Cells Against Relapsed or Refractory B Cell Non-Hodgkin Lymphomas.

Background: The administration of second- or third-generation anti-CD19 chimeric antigen receptor (CAR) T cells has remarkably improved the survival of patients with relapsed or refractory B cell malignancies. However, there are limited clinical results from fourth-generation CAR-T cell therapy, and the factors affecting response rate and survival have not been fully determined. Methods: Lymphoma patients with progression or relapse after intensive treatments, including hematopoietic stem cell transplantation, and life expectancy >2 months were enrolled in the study. Peripheral lymphocytes were collected through apheresis, and magnetically selected T cells were lentivirally transduced with a 4th-generation CAR featuring an anti-CD19 CAR and the iCasp9 suicide switch (4SCAR19). The patients received 4SCAR19 T cell infusion after approximately seven days of expansion and a conditioning regimen comprising cyclophosphamide/fludarabine. The efficacy, safety, and risk factors were evaluated. Results: A total of 21 patients with relapsed/refractory B cell non-Hodgkin lymphoma were enrolled and received 4SCAR19 T cell infusions at a median dose of 8.9×105 CAR-T cells/kg. The overall response rate was 67% [95% confidence interval (CI), 43 to 85], with 43% of patients achieving a complete response and 24% having a partial response. The overall and complete response rates were 58 and 33% in the diffuse large B-cell lymphoma (DLBCL) group and 78 and 56% in the non-DLBCL group, respectively. The median overall survival was 23.8 months (95% CI, not reached), with a median follow-up of 13.7 months. Factors affecting overall survival were International Prognostic Index (IPI), disease type, and remission status after CAR-T cell treatment. The most common adverse events of grade 3 or 4 during treatment were neutropenia (76%), leukopenia (71%), and thrombocytopenia (29%). The incidence of cytokine release syndrome (CRS) was 14%, and all cases were grade 1. One patient developed grade 3 neurotoxicity. No deaths were attributed to infusion of 4SCAR19 T cells, CRS, or neurotoxicity. Conclusions: In this study, patients with relapsed or refractory B cell non-Hodgkin's lymphoma who received 4SCAR19 T cell therapy had durable responses and few of adverse events. The IPI model is suitable for evaluating the prognosis of patients receiving CAR-T cell therapy. Trial registration: Chinese Clinical Trial Registry (http://www.chictr.org.cn): ChiCTR-OOC-16007779.

Endothelial damage and a thin intercellular fibrin network promote haemorrhage in acute promyelocytic leukaemia.

BACKGROUND: The role of vascular endothelium in acute promyelocytic leukaemia (APL) remains unknown. We aimed to investigate the mechanisms by which APL cells interact with endothelial cells (ECs) and to further explore how the endothelium affects bleeding as well as therapeutic interventions. METHOD: APL cells and an original APL cell line, NB4 cells, were used for experiments. The effects of leukaemic cells on ECs were analyzed in vitro and in vivo. Moreover, the endothelial barrier function and procoagulant activity were detected. An APL mouse model was established for in vivo studies. FINDINGS: APL cells interacted with ECs via ICAM-1 and VCAM-1 receptors to disrupt endothelial integrity. This binding activated MLCK signaling, resulting in the trans-endothelial passage of protein and red blood cells (RBCs). Combined treatment with asiatic acid or anti-adhesion receptor antibody inhibited the response of ECs to APL cells, thereby preventing APL-associated haemorrhage in vitro and in vivo. Activated ECs exhibited a procoagulant phenotype after phosphatidylserine exposure. Plasma from APL patients formed a thin fibrin network between procoagulant ECs, and this intercellular fibrin decreased the passage of albumin and RBCs. Ex vivo addition of fibrinogen further enhanced this barrier function in a dose-dependent manner. INTERPRETATION: Endothelial damage induced by leukaemic cell adherence promotes haemorrhaging in APL. Stabilization of ECs, decreasing adhesion receptor expression, and increasing fibrinogen transfusion levels may be a new therapeutic avenue to alleviate this fatal bleeding complication. FUNDING: National Science Foundation of China (81670128, 81873433).

Arterial spin labeling-MR may be an alternative to SPECT for evaluating cerebral perfusion in patients with unilateral middle cerebral artery stenosis.

OBJECTIVE: Cerebral blood flow (CBF) mapping of single-photon emission tomography (SPECT) is considered a gold standard for evaluating cerebral perfusion. However, invasiveness, high costs and strict technical requirements can limit its clinical use. We aimed to evaluate the concordance of CBF maps obtained from SPECT and pseudo-continuous arterial spin labeling magnetic resonance (PCASL-MR) imaging for evaluating cerebral perfusion. METHODS: PCASL-MR/SPECT-CBF maps were obtained from 16 eligible patients with unilateral middle cerebral artery stenosis (MCAS). Three slices (basal ganglia, semi-oval center and cerebellum) on both PCASL-MR and SPECT maps were divided into different regions of interest (ROIs) according to the ASPECT criterion, arterial territories, and cerebral hemispheres, respectively. The concordance of the two types of CBF maps and the specificity and sensitivity of PCASL-MR imaging on predicting regional hypoperfusion were calculated. RESULTS: A total of 448 ROIs were divided according to the ASPECT criterion, 192 ROIs partitioned in accordance with arterial territories, and 96 ROIs delineated based on cerebral hemispheres were analyzed. PCASL-MR imaging exhibited 83.78% to 100% sensitivity, 90.19% to 95.83% specificity for detection of hypoperfusion. Qualitative analyses revealed a strong concordance between PCASL-MR and SPECT on reflecting regional cerebral hypoperfusion (Kappa coefficient = 0.662-0.920, p < 0.01). Semi-quantitative analysis by ΔCBF revealed moderate consistency (Spearman correlation coefficient = 0.610-0.571). CONCLUSIONS: Our findings suggest that PCASL-MR may be a promising non-invasive, inexpensive alternative to SPECT for evaluating cerebral perfusion accurately in patients with symptomatic MCAS.

Quantitative susceptibility mapping of carotid plaques using nonlinear total field inversion: Initial experience in patients with significant carotid stenosis.

PURPOSE: To develop a nonlinear preconditioned total field-inversion algorithm using the MEDI toolbox (MEDInpt) for robust QSM of carotid plaques and evaluate its performance in comparison with a local field-inversion algorithm (STI Suite) previously applied to carotid QSM. METHODS: Numerical simulation and in vivo carotid QSM were performed to compare the MEDInpt and STI Suite algorithms. Multicontrast MRI was used as the reference standard for detecting calcified plaque and intraplaque hemorrhage (IPH). A total of 5 healthy volunteers and 11 patients with at least one significant carotid artery stenosis were enrolled in this study. RESULTS: In the numerical carotid phantom, the relative susceptibility errors for calcified plaque and IPH were reduced from -63.2% and -56.5% with STI Suite to -13.0% and -24.2% with MEDInpt, respectively. In humans, MEDInpt provided a higher QSM quality score and better detection of calcification and IPH than STI Suite. Although all calcifications and IPHs detected on multicontrast MRI could be seen on QSM obtained with MEDInpt, only 50% of calcified plaques and 83% of IPHs could be captured on QSM obtained with STI Suite. CONCLUSION: MEDInpt can resolve calcification and IPH in advanced atherosclerotic carotid plaques. Compared with STI Suite, MEDInpt provided better QSM quality and has the potential to improve the detection of these plaque components.

Quantitative Susceptibility Mapping for Characterization of Intraplaque Hemorrhage and Calcification in Carotid Atherosclerotic Disease.

BACKGROUND: Carotid artery intraplaque hemorrhage (IPH), an unstable component of atherosclerosis, is associated with an increased risk of stroke. PURPOSE: To investigate quantitative susceptibility mapping (QSM) as a tool for the evaluation of IPH and calcification in vivo. STUDY TYPE: Prospective. POPULATION: Ten healthy volunteers and 15 patients. FIELD STRENGTH/SEQUENCE: 3.0T Susceptibility-weighted imaging (SWI), magnetization-prepared rapid acquisition with gradient echo (MP-RAGE), T1 -weighted sampling perfection with application of optimized contrasts using different flip angle evolution (T1 -SPACE), T2 -weighted turbo spin-echo (T2 WI), and time-of-flight (TOF) sequences. ASSESSMENT: The vessel wall area of the carotid artery was measured with QSM and compared with T1 -SPACE on healthy volunteers. Four radiologists, blinded to clinical history and patient identity, determined the presence and area of IPH on MP-RAGE and QSM, as well as the area of calcification on T1 -SPACE and QSM. STATISTICAL TESTS: Bland-Altman analysis, Pearson correlation coefficients, linear regression analyses were performed to evaluate the concordance of area measurements. Cohen's kappa (κ) was analyzed to determine the agreement between IPH detections. The paired t-test was used to compare the group differences. RESULTS: In 423 matched slices, 20.1% (85/423) and 19.6% (83/423) were detected to have IPH on MP-RAGE and QSM, respectively. IPH detection by QSM and MP-RAGE showed good agreement (κ = 0.822, P < 0.001) between the two methods. There was no significant difference in IPH area measurements between QSM and MP-RAGE (7.28 mm2 ± 6.41 vs. 7.16 mm2 ± 5.99, P = 0.575). There was no significant difference in calcification area measurement between QSM and T1 -SPACE (3.51 mm2 ± 1.78 vs. 3.41 mm2 ± 2.02, P = 0.783). DATA CONCLUSION: QSM is a novel imaging tool for the identification of IPH in patients with carotid atherosclerosis and enables differentiation of IPH and calcification. EVIDENCE LEVEL: 1 TECHNICAL EFFICACY: Stage 1 J. Magn. Reson. Imaging 2020;52:534-541.

Phosphatidylserine-exposing blood cells, microparticles and neutrophil extracellular traps increase procoagulant activity in patients with pancreatic cancer.

Patients with pancreatic cancer (PC) are at increased risk of venous thrombosis, but the precise mechanisms of hypercoagulable state in PC remain unclear. We aimed to identify how phosphatidylserine positive (PS+) blood cells (BCs), PS+ microparticles (MPs) and neutrophil extracellular traps (NETs) regulate procoagulant activity (PCA) in PC, and to assess the relationship between PCA and PC staging. A total of 83 PC patients with different stages of disease were compared to 30 healthy controls, with confocal microscopy and flow cytometry used to assess MP and cellular PS exposure. MP and cell PCA was determined using both fibrin production assays and procoagulant enzyme complex analyses, and coagulation time was further measured. Patients with stage I PC and healthy controls exhibited significantly lower frequencies of PS+ MPs and BCs relative to those with more advanced disease, which may partly due to the increased levels of inflammation cytokines in advanced disease. Functional coagulation assays indicated that PS+ MPs and BCs derived from patients with stage II/III/IV PC directly contribute to elevated FXa, thrombin, and fibrin formation, and to more rapid coagulation relative to healthy control samples. In inhibition assays, lactadherin, which antagonizes PS, led to a roughly 80% inhibition of PCA. We further used isolated NETs to stimulate endothelial cells, revealing that this led to morphological changes including retraction from cell-cell junctions and a more pro-coagulative phenotype, with DNase I and activated protein C treatment reversing these changes. In patients with stage III PC, curative resection surgery significantly reduced PCA, whereas non-curative surgery did not have a marked impact based on studies of pre- and post-operative samples. These results highlight the pathogenic activity of PS+ cells, MPs, and NETs in promoting a prothrombotic environment within individuals suffering from advanced PC. Targeting PS and NETs in these patients may thus be a viable means of preventing pathological thrombosis.