Activated partial thromboplastin time predicts mortality in patients with severe fever with thrombocytopenia syndrome: A multicenter study in north China.

Background: Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious disease with high lethality. This study aimed to determine whether prolonged activated partial thromboplastin time (APTT) predicted SFTS mortality. Methods: SFTS patients were enrolled from 6 hospitals in the north China. Subjects were divided into training cohort and 5 externally validation cohorts. The least absolute shrinkage and selection operator Cox regression model was performed to screen potential prognostic factors. Risk factors were analyzed using multivariable regression models. Prognostic models were established by Cox regression and random survival forest (RSF) methods, and evaluated regarding discrimination, validity and clinical benefit. Time-dependent receiver operating characteristic (ROC) curve was used to evaluate the predictive effectiveness of variables. Results: 1332 SFTS cases were included, in which 211 patients died. Six potential prognostic factors were screened, and pulse, breath, APTT and aspartic transaminase (AST) were independently associated with mortality in both training cohort (Yantai, N = 791) and external validation cohort (N = 541). APTT was steadily correlated with the fatality (HR: 1.039-1.144; all P < 0.01) in each five sub-validation cohorts (Dandong, Dalian, Tai'an, Qingdao and Beijing). RSF model with variables of APTT, AST, pulse and breath had considerable prognostic effectiveness, which APTT showed the highest prognostic ability with the area under the curve of 0.848 and 0.787 for 7-day and 14-day survival, respectively. Survival differences were found between high and low levels of APTT for mortality using 50s as the optimal cut-off. Conclusions: SFTS patients have prolonged APTT, which is an independent risk factor for fatality. APTT≥50s was recommended as a biomarker to remind physicians to monitor and treat patients more aggressively to improve clinical prognosis.

[Optimization and verification of conditions for induction of neutrophil extracellular traps in vitro].

This study aims to optimize the conditions for the formation of neutrophil extracellular traps(NETs) in vitro, so as to establish a relatively stable experimental research platform. Different conditions were compared, including commonly used laboratory animals(rats and mice) and a variety of cell sources(bone marrow neutrophils and peripheral blood neutrophils separated by percoll density gradient centrifugation). Different inducers like lipopolysaccharide(LPS) and phorbol 12-myristate 13-acetate(PMA) were used for induction in vitro. Myeloperoxidase(MPO)/citrullinated histone H3(CitH3)/DAPI immunofluorescence and cell free DNA(cf-DNA) content determination were used for comprehensive evaluation to screen the optimal conditions for the formation of NETs induced in vitro. Furthermore, the stability of the selected conditions for inducing the formation of NETs in vitro was evaluated by tetramethylpyrazine(TMP), an active component in Chinese herbal medicines. The results showed that coated poly-D-lysine(PDL) induced the formation of NETs in bone marrow neutrophils of mice to a certain extent. Both LPS and PMA significantly up-regulated the protein levels of MPO and CitH3 in mouse bone marrow neutrophils and elevated the cfDNA level in the supernatant of rat peripheral blood neutrophils. The cfDNA level in the PMA-induced group increased more significantly than that in the LPS-induced group(P<0.05). The results of immunofluorescence staining showed that the expression of MPO and CitH3 in mouse bone marrow neutrophils, rat bone marrow neutrophils, and rat peripheral blood neutrophils were significantly increased after PMA induction, especially in rat peripheral blood neutrophils. TMP significantly down-regulated the protein levels of MPO, CitH3, and neutrophil elastase(NE) in rat peripheral blood neutrophils induced by PMA. In conclusion, treating the peripheral blood neutrophils of rats with PMA is the optimal condition for inducing the formation of NETs in vitro. This study provides an optimal platform for in vitro studies based on NETs and a basis for studying the effects of traditional Chinese medicines targeting NETs.

Composition and Function of Neutrophil Extracellular Traps.

Neutrophil extracellular traps (NETs) are intricate fibrous structures released by neutrophils in response to specific stimuli. These structures are composed of depolymerized chromatin adorned with histones, granule proteins, and cytosolic proteins. NETs are formed via two distinct pathways known as suicidal NETosis, which involves NADPH oxidase (NOX), and vital NETosis, which is independent of NOX. Certain proteins found within NETs exhibit strong cytotoxic effects against both pathogens and nearby host cells. While NETs play a defensive role against pathogens, they can also contribute to tissue damage and worsen inflammation. Despite extensive research on the pathophysiological role of NETs, less attention has been paid to their components, which form a unique structure containing various proteins that have significant implications in a wide range of diseases. This review aims to elucidate the components of NETs and provide an overview of their impact on host defense against invasive pathogens, autoimmune diseases, and cancer.

Leukotriene B4-induced neutrophil extracellular traps impede the clearance of Pneumocystis.

Pneumocystis pneumonia (PCP) is a fungal pulmonary disease with high mortality in immunocompromised patients. Neutrophils are essential in defending against fungal infections; however, their role in PCP is controversial. Here we aim to investigate the effects of neutrophil extracellular traps (NETs) on Pneumocystis clearance and lung injury using a mouse model of PCP. Intriguingly, although neutrophils play a fundamental role in defending against fungal infections, NETs failed to eliminate Pneumocystis, but instead impaired the killing of Pneumocystis. Mechanically, Pneumocystis triggered Leukotriene B4 (LTB4)-dependent neutrophil swarming, leading to agglutinative NET formation. Blocking Leukotriene B4 with its receptor antagonist Etalocib significantly reduced the accumulation and NET release of neutrophils in vitro and in vivo, enhanced the killing ability of neutrophils against Pneumocystis, and alleviated lung injury in PCP mice. This study identifies the deleterious role of agglutinative NETs in Pneumocystis infection and reveals a new way to prevent NET formation, which provides new insights into the pathogenesis of PCP.

Identification of CCL20 as a prognostic predictor for severe fever with thrombocytopenia syndrome based on plasma proteomics.

BACKGROUND: Severe fever with thrombocytopenia syndrome (SFTS), a lethal tick-borne hemorrhagic fever, prompted our investigation into prognostic predictors and potential drug targets using plasma Olink Proteomics. METHODS: Employing the Olink assay, we analyzed 184 plasma proteins in 30 survivors and 8 non-survivors of SFTS. Validation was performed in a cohort of 154 SFTS patients using enzyme-linked immunosorbent assay. We utilized the Drug Gene Interaction database to identify protein-drug interactions. RESULTS: Non-survivors exhibited 110 differentially expressed proteins (DEPs) compared to survivors, with functional enrichment in the cell chemotaxis-related pathway. Thirteen DEPs, including C-C motif chemokine 20 (CCL20), calcitonin gene-related peptide alpha and Pleiotrophin, were associated with multiple organ dysfunction syndrome. CCL20 emerged as the top predictor of death, demonstrating an area under the curve of 1 (P = .0004) and 0.9033 (P < .0001) in the discovery and validation cohort, respectively. Patients with CCL20 levels exceeding 45.74 pg/mL exhibited a fatality rate of 45.65%, while no deaths occurred in those with lower CCL20 levels. Furthermore, we identified 202 FDA-approved drugs targeting 37 death-related plasma proteins. CONCLUSIONS: Distinct plasma proteomic profiles characterize SFTS patients with different outcomes, with CCL20 emerging as a novel, sensitive, accurate, and specific biomarker for predicting SFTS prognosis.

Sepsis induces non-classic innate immune memory in granulocytes.

Secondary infection in patients with sepsis triggers a new wave of inflammatory response, which aggravates organ injury and increases mortality. Trained immunity boosts a potent and nonspecific response to the secondary challenge and has been considered beneficial for the host. Here, using a murine model of polymicrobial infection, we find that the primary infection reprograms granulocytes to boost enhanced inflammatory responses to the secondary infection, including the excessive production of inflammatory cytokines, respiratory burst, and augmented phagocytosis capacity. However, these reprogramed granulocytes exhibit "non-classic" characteristics of innate immune memory. Two mechanisms are independently involved in the innate immune memory of granulocytes: a metabolic shift in favor of glycolysis and fatty acid synthesis and chromatin remodeling leading to the transcriptional inactivity of genes encoding inhibitors of TLR4-initiated signaling pathways. Counteracting the deleterious effects of stressed granulocytes on anti-infection immunity might provide a strategy to fight secondary infections during sepsis.

Simiao Yong'an decoction ameliorates murine collagen-induced arthritis by modulating neutrophil activities: An in vitro and in vivo study.

ETHNOPHARMACOLOGICAL RELEVANCE: Rheumatoid arthritis (RA) is a common systemic autoimmune disease with high morbidity and disability rate. Currently, there is no effective allopathic treatment for RA, and most of the drugs provoke many adverse effects. Simiao Yong'an decoction (SMYAD) is a traditional Chinese prescription for the treatment of sore and gangrene caused by hot poison. With the development of pharmacology and clinical research, SMYAD has remarkable anti-inflammatory properties and has been used for RA treatments for years. AIM OF THE STUDY: This study aimed to investigate the anti-arthritic effect of SMYAD and further explore the immunopharmacological mechanisms. MATERIALS AND METHODS: Arthritis was induced in DBA/1 mice by two-time immunizations. Collagen-induced rheumatoid arthritis (CIA) mice were divided into 4 groups: control, model, methotrexate (MTX), and SMYAD group (n = 6). The administration groups were given MTX (0.5 mg/kg/3 d) and SMYAD (4.5 g/kg/d) by gavage from day 14. The arthritis index (AI) score was evaluated every 3 days after the second immunization. Hematoxylin and eosin (H&E) staining, Safranin-O fast green staining, Trap staining, and Micro-CT were used to measure the histopathology injuries and bone destruction of joints. Granulocyte changes in the spleen, bone marrow, and period blood were analyzed by flow cytometry. The expression of inflammatory cytokines and chemokines in joints were detected by qRT-PCR. SMYAD-containing serum was obtained from SD rats gavaged with SMYAD. Neutrophils were isolated from peripheral blood and bone marrow for the in vitro experiments of transwell cell assay, apoptosis assay, reactive oxygen species (ROS) generation and neutrophil extracellular traps (NETs) formation. RESULTS: SMYAD significantly relieved arthritis severity in CIA mice. The AI score was significantly decreased in the SMYAD group compared with the model group. Additionally, SMYAD alleviated inflammatory infiltration, cartilage damage, osteoclast formation, and bone damage in the ankle joints. In the flow cytometry assay, SMYAD significantly reduced granulocytes number in the spleen and bone marrow, while increased in peripheral blood. Furthermore, compared with the CIA group, SMYAD suppressed the mRNA levels of inflammatory factors including TNF-α, IL-1ß, IL-6 and chemokines CXCL1, CXCL2, and IL-8 in the inflamed joints. In the in vitro studies, 20% SMYAD-containing serum effectively inhibited the migration of neutrophils, promoted neutrophils apoptosis, reduced ROS production and NETs formation. CONCLUSION: Collectively, our results demonstrated that SMYAD effectively restrained arthritis in CIA mice by modulating neutrophil activities.

Multi-target regulation of pro-inflammatory cytokine production by transcription factor Blimp-1.

OBJECTIVE: Cytokine storm syndrome is a fatal condition related to infectious and autoimmune diseases. Here, we aim to investigate the regulatory mechanisms of Blimp-1 on multiple cytokine production. METHODS: The Blimp1 shRNA was transfected into RAW264.7 macrophages, followed by Toll-like receptor (TLR) ligand stimulation. The mRNA and protein levels of cytokines were detected by real-time PCR and flow cytometric bead array. The nuclear translocation of AP-1 and NF-κB p65 was measured by immunofluorescence staining. The transcriptional activity was detected by luciferase reporter assay with 5 × NF-κB reporter or with IL6 promoter reporter. RESULTS: Blimp-1 significantly inhibited the expression and secretion of IL-1ß, IL-6, and IL-18 in macrophages during stimulation with a variety of TLR ligands. The immunofluorescence staining results showed that Blimp-1 strictly controlled the nuclear translocation of NF-κB p65 in LPS-challenged macrophages. Furthermore, Blimp-1 directly inhibited the transcriptional activity of NF-κB and the transcription of IL6 gene. CONCLUSION: Blimp-1 represses the production of multiple pro-inflammatory cytokines by directly binding the genomic region and restricting the nuclear translocation and transcriptional activity of NF-κB. This finding may provide potential therapeutic strategies for the cytokine storm-related diseases.

The effect of age on the clinical characteristics and innate immune cell function in the patients with abdominal sepsis.

Sepsis is a life-threatening dysregulated host response to infection that compromises organ health, and abdominal sepsis is a commonly presenting critical illness in intensive care units (ICU). In this study, we investigate the effect of age on clinical sepsis characteristics and innate immune cells (neutrophils and monocytes) functionality in abdominal sepsis patients. We recruited 32 patients with abdominal sepsis from the Beijing Ditan Hospital's ICU from February 2021 to September 2021, and selected 18 healthy volunteers that were age- and sex-matched as controls for a prospective cohort study. Elderly abdominal sepsis patients (age >65 years) had the following altered characteristics compared to nonelderly patient controls: lower mean arterial pressure, monocytes percentage, and red blood cell volume distribution width (p < 0.05); higher neutrophils percentage and neutrophils-to-lymphocytes ratio (p < 0.05); significantly increased monocyte-produced reactive oxygen (p < 0.05); increases neutrophilic secretion of TNF-α, as well as lower monocytic secretion of TNF-α (p < 0.05); higher neutrophil percentage (which was significantly higher in peripheral blood than monocyte percentage). Elderly patients also had significantly increased phagocytic activity in their neutrophils and monocytes (p < 0.05), significantly reduced neutrophils-produced reactive oxygen (p < 0.001), and significantly increased TNF-α secretion by monocytes and neutrophils (p < 0.05). We found that elderly patients have decreased immune cell function and increased release of cytokines compared to younger patients, suggesting individualized treatment plans targeting the elderly septic microenvironment could help prevent organ failure in elderly septic patients and improves patient survival.

Macrophages evoke autophagy of hepatic stellate cells to promote liver fibrosis in NAFLD mice via the PGE2/EP4 pathway.

The pathogenesis of liver fibrosis in nonalcoholic fatty liver disease (NAFLD) remains unclear and the effective treatments have not been explored yet. The activation of hepatic stellate cells (HSCs) is considered as the most critical factor in the progression of liver fibrosis and cirrhosis. Autophagy has recently been identified as a new mechanism to regulate HSC activation. Here, we found that liver macrophages were polarized toward type 2 (M2) during the progression of nonalcoholic steatohepatitis (NASH) and liver fibrosis in both patients and NAFLD mice. Using the methionine-choline-deficient (MCD) diet NAFLD murine model and the in vitro cell culture system, we identified that the M2 macrophages promoted HSC autophagy by secreting prostaglandin E2 (PGE2) and binding its receptor EP4 on the surface of HSCs, which consequently enhanced HSC activation, extracellular matrix deposition, and liver fibrosis. Mechanistically, PGE2/EP4 signals enhanced HSC autophagy through the Erk pathway. A specific PGE2/EP4 antagonist E7046 significantly inhibited M2 macrophage-mediated HSC autophagy and improved liver fibrosis and histopathology in NAFLD mice. Our study provides novel mechanistic insights into the regulation of HSC activation and liver fibrosis. Our findings suggest that the PGE2/EP4 pathway is a promising therapeutic target to prevent NASH progression into cirrhosis.

Mechanism of taurine reducing inflammation and organ injury in sepsis mice.

The fundamental basis for the pathogenesis of sepsis is an inflammatory imbalance, which is considered to be the main target for treatment. Taurine is an intracellular free amino acid that has anti-inflammatory and antioxidant effects. To investigate the protective mechanism of taurine in sepsis, we used in vitro and in vivo experiments to explore the effects of taurine on neutrophil and monocyte immune function. Metabolomic analysis showed large amounts of taurine in neutrophils and monocytes and a dramatic decrease in taurine levels after LPS exposure. Taurine supplementation decreased the expressions of tumor necrosis factor-α (TNF-α), interleukin-1ß (IL-1ß) in LPS-challenged neutrophils and monocytes and reduced the formation of neutrophil extracellular traps by restricting reactive oxygen species. Moreover, taurine protected septic mice from death, improved tissue injuries in the lung, liver, and kidney by reducing neutrophil infiltration and TNF-α production. Our data indicate that a supplement with taurine might be a promising therapeutic strategy for sepsis to reduce hyper inflammation and improve multi-organ dysfunctions.

Role of neutrophils in acute viral infection.

Neutrophils play multiple roles in acute viral infections. They restrict viral replication and diffusion through phagocytosis, degranulation, respiratory burst, secretion of cytokines, and the release of neutrophil extracellular traps, as well as, activate the adaptive immune response. However, the overactivation of neutrophils may cause tissue damage and lead to poor outcomes. Additionally, some characteristics and functions of neutrophils, such as cell number, lifespan, and antiviral capability, can be influenced while eliminating viruses. This review provides a general description of the protective and pathological roles of neutrophils in acute viral infection.

Carboxypeptidase B blocks ex vivo activation of the anaphylatoxin-neutrophil extracellular trap axis in neutrophils from COVID-19 patients.

BACKGROUND: Thrombosis and coagulopathy are highly prevalent in critically ill patients with COVID-19 and increase the risk of death. Immunothrombosis has recently been demonstrated to contribute to the thrombotic events in COVID-19 patients with coagulopathy. As the primary components of immunothrombosis, neutrophil extracellular traps (NETs) could be induced by complement cascade components and other proinflammatory mediators. We aimed to explore the clinical roles of NETs and the regulation of complement on the NET formation in COVID-19. METHODS: We recruited 135 COVID-19 patients and measured plasma levels of C5, C3, cell-free DNA and myeloperoxidase (MPO)-DNA. Besides, the formation of NETs was detected by immunofluorescent staining and the cytotoxicity to vascular endothelial HUVEC cells was evaluated by CCK-8 assay. RESULTS: We found that the plasma levels of complements C3 and MPO-DNA were positively related to coagulation indicator fibrin(-ogen) degradation products (C3: r = 0.300, p = 0.005; MPO-DNA: r = 0.316, p = 0.002) in COVID-19 patients. Besides, C3 was positively related to direct bilirubin (r = 0.303, p = 0.004) and total bilirubin (r = 0.304, p = 0.005), MPO-DNA was positively related to lactate dehydrogenase (r = 0.306, p = 0.003) and creatine kinase (r = 0.308, p = 0.004). By using anti-C3a and anti-C5a antibodies, we revealed that the complement component anaphylatoxins in the plasma of COVID-19 patients strongly induced NET formation. The pathological effect of the anaphylatoxin-NET axis on the damage of vascular endothelial cells could be relieved by recombinant carboxypeptidase B (CPB), a stable homolog of enzyme CPB2 which can degrade anaphylatoxins to inactive products. CONCLUSIONS: Over-activation in anaphylatoxin-NET axis plays a pathological role in COVID-19. Early intervention in anaphylatoxins might help prevent thrombosis and disease progression in COVID-19 patients.

Partial recovery of disturbed V-J pairing profiles of T-cell receptor in people living with HIV receiving long-term antiretroviral therapy.

Chronic human immunodeficiency virus (HIV) infection not only causes a gradual loss of CD4+ T cells but also leads to a disturbance of the T cell receptor (TCR) repertoire. In people living with HIV (PLWH), monitoring TCR repertoire is challenged by the inconsistency of complementarity determining region 3 (CDR3) and limited cell numbers in clinical samples. Thus, a quantitative method is necessary for monitoring the TCR repertoire in PLWH. We characterized the TCR V-J pairing profile of naïve and memory CD4+ T cells in healthy donors, HIV-infected antiretroviral therapy (ART)-naïve patients and long-term (over 5 years) ART-experienced patients by performing TCR sequencing. We developed a V-J index with 18 parameters which were subdivided into five categories (expression coverage, cumulative percentage of the top tenth percentile, diversity, intra-individual similarity and inter-individual similarity). In ART-naïve patients, 14 of the 18 parameters were significantly altered. Long-term ART recovered ten parameters. The four unrecovered parameters were related to inter-individual similarity. Therefore, these findings indicate that long-term ART could only partially recover TCR V-J pairs and introduce newly impacted V-J pairs. Moreover, these results provide new insights into the V-J pairing of the TCR and into the disturbance of TCR repertoire in HIV infection.

Circulating Rather Than Alveolar Extracellular Deoxyribonucleic Acid Levels Predict Outcomes in Influenza.

BACKGROUND: High levels of circulating neutrophil extracellular traps (NETs) are associated with a poor prognosis in influenza A infection. It remains unclear whether NETs in the plasma or bronchoalveolar lavage fluid (BALF) can predict clinical outcomes in influenza. METHODS: One hundred eighteen patients who were diagnosed with H1N1 influenza in 2017-2018 were recruited. The NETs were assessed in plasma and BALF samples by quantifying cell-free deoxyribonucleic acid (cfDNA) and protein-DNA complexes. Predictions of severe illness and 60-day mortality were analyzed with receiver operating characteristic curves. RESULTS: The NET levels were significantly elevated in the BALF and contributed to the pathology of lungs, yet it was not associated with disease severity or mortality in patients severely infected with H1N1. Plasma NET levels were significantly increased in the patients with severe influenza and positively correlated with the oxygen index and sequential organ failure assessment scores. High levels of plasma cfDNA (>286.6 ng/mL) or histone-bound DNA (>9.4 ng/mL) discriminated severe influenza from mild, and even higher levels of cfDNA (>306.3 ng/mL) or histone-bound DNA (>23.1 ng/mL) predicted fatal outcomes in severely ill patients. CONCLUSIONS: The cfDNA and histone-bound DNA in plasma represent early predictive biomarkers for the prognosis of influenza.

High Levels of Circulating Cell-free DNA Are Associated With a Poor Prognosis in Patients With Severe Fever With Thrombocytopenia Syndrome.

BACKGROUND: The extensive geographical distribution and high mortality rate of severe fever with thrombocytopenia syndrome (SFTS) have made it an important threat to public health. Neutrophil extracellular traps (NETs) can be activated by a variety of pathogens and are associated with thrombocytopenia in viral infections. We aimed to identify NET production and its predictive value for disease progression and prognosis in patients with SFTS. METHODS: A prospective study was performed with a multicenter cohort of patients with SFTS (n = 112) to quantify serum NET levels. Three markers of NETs-namely, cell-free DNA (cfDNA), myeloperoxidase-DNA complexes, and lactoferrin-DNA complexes-were measured with PicoGreen double-stranded DNA assays and enzyme-linked immunosorbent assays. Receiver operating characteristic curves and multivariate regression analyses were performed to calculate the predictive value of cfDNA levels. RESULTS: SFTS was characterized by pronounced NET formation. The serum levels of NETs changed dynamically during disease progression, with an inverse pattern of the trends of platelet and neutrophil levels. High cfDNA levels were strongly associated with multiple pathological processes, including coagulopathy, myocardial damage, liver dysfunction, and the development of encephalopathy. A high level of cfDNA (>711.7 ng/mL) at the time of the initial diagnosis predicted severe illness in patients with SFTS (odds ratio, 8.285 [95% confidence interval, 2.049-33.503]; P = .003). CONCLUSIONS: This study has a high degree of clinical impact for identification of cfDNA as a useful predictive biomarker of clinical outcomes of SFTS.

Xijiao Dihuang Decoction () and Rehmannia glutinosa Libosch. protect mice against lipopolysaccharide and tumor necrosis factor alpha-induced acute liver failure.

OBJECTIVE: To investigate the hepatoprotective effect of Xijiao Dihuang Decoction (, XJDHD) on lipopolysaccharide (LPS)- and tumor necrosis factor alpha (TNF-α)-induced acute liver failure (ALF) as well as the underlying mechanism of action, and to clarify the key herbs and components of XJDHD. METHODS: LPS/D-galactosamine (D-GalN) or TNF-α/D-GalN were intraperitoneally injected into C57BL/6J mice to induce ALF. Simultaneously, XJDHD or its individual herbs and components were orally administered. Survival rates, transaminase levels in serum, and hepatic histology were examined to evaluate the effects of XJDHD. The terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay and real-time polymerase chain reaction were additionally performed to expound the mechanism underlying the anti-apoptotic activity of XJDHD. RESULTS: Oral administration of XJDHD protected mice from lethal liver failure induced by LPS and TNF-α, with notable amelioration of liver injury in histology and a significant decrease in transaminase levels in serum. XJDHD significantly inhibited apoptosis of hepatocytes and enhanced expression of the antiapoptosis genes, c-Flip, Iap1, Gadd45b and A20. In addition, Rehmannia glutinosa Libosch. was identified as the key herb of XJDHD and galactose as the effective component of Rehmannia glutinosa Libosch. that protects against ALF. CONCLUSIONS: XJDHD inhibits TNF-α-induced apoptosis of hepatocytes by promoting the expression of nuclear factor κ B-regulated anti-apoptotic genes. Rehmannia glutinosa Libosch. is the effective herb of XJDHD and galactose is an active component in this protection.

High Level of Neutrophil Extracellular Traps Correlates With Poor Prognosis of Severe Influenza A Infection.

Background: Most patients with severe infection with influenza A virus (IAV) progress to acute respiratory distress syndrome and even multiple organ dysfunction syndrome (MODS). Neutrophil extracellular traps (NETs) can be induced by pathogens and are responsible for immune tissue damage. We conducted a prospective study on the production and effects of NETs in H7N9 and H1N1 patients. Methods: We investigated NET production in plasma and supernatant of cultured neutrophils by measuring cell-free deoxyribonucleic acid (DNA) and myeloperoxidase (MPO)-DNA complexes with PicoGreen dye and enzyme-linked immunosorbent assay methods, respectively. We also observed NET structure by immunofluorescence staining. Results: We found that patients with severe influenza showed elevated plasma NET level on the day of admission. Neutrophils from these patients showed higher capacity to release MPO-DNA complex in response to interleukin-8 or lipopolysaccharide stimulation. We also found that NETs from H7N9 and H1N1 patients increased the permeability of alveolar epithelial cells, and, consequently, NET production was positively correlated with acute physiology and chronic health evaluation (APACHE) II score and MODS. Conclusions: These data indicate that high level of NETs contributes to lung injury and is correlated with severity of disease. Thus, NETs might be a key factor to predict the poor prognosis in IAV patients.

Blimp-1 impairs T cell function via upregulation of TIGIT and PD-1 in patients with acute myeloid leukemia.

BACKGROUND: T cell immunoglobulin and immunoreceptor tyrosine-based inhibitory motif (ITIM) domain (TIGIT) and programmed cell death protein 1 (PD-1) are important inhibitory receptors that associate with T cell exhaustion in acute myeloid leukemia (AML). In this study, we aimed to determine the underlying transcriptional mechanisms regulating these inhibitory pathways. Specifically, we investigated the role of transcription factor B lymphocyte-induced maturation protein 1 (Blimp-1) in T cell response and transcriptional regulation of TIGIT and PD-1 in AML. METHODS: Peripheral blood samples collected from patients with AML were used in this study. Blimp-1 expression was examined by flow cytometry. The correlation of Blimp-1 expression to clinical characteristics of AML patients was analyzed. Phenotypic and functional studies of Blimp-1-expressing T cells were performed using flow cytometry-based assays. Luciferase reporter assays and ChIP assays were applied to assess direct binding and transcription activity of Blimp-1. Using siRNA to silence Blimp-1, we further elucidated the regulatory role of Blimp-1 in the TIGIT and PD-1 expression and T cell immune response. RESULTS: Blimp-1 expression is elevated in T cells from AML patients. Consistent with exhaustion, Blimp-1+ T cells upregulate multiple inhibitory receptors including PD-1 and TIGIT. In addition, they are functionally impaired manifested by low cytokine production and decreased cytotoxicity capacity. Importantly, the functional defect is reversed by inhibition of Blimp-1 via siRNA knockdown. Furthermore, Blimp-1 binds to the promoters of PD-1 and TIGIT and positively regulates their expression. CONCLUSIONS: Our study demonstrates an important inhibitory effect of Blimp-1 on T cell response in AML; thus, targeting Blimp-1 and its regulated molecules to improve the immune response may provide effective leukemia therapeutics.