Alterations of dendritic cells in sepsis: featured role in immunoparalysis

Lactate's impact on immune cells in sepsis: unraveling the complex interplay

Lactate significantly impacts immune cell function in sepsis and septic shock, transcending its traditional view as just a metabolic byproduct. This review summarizes the role of lactate as a biomarker and its influence on immune cell dynamics, emphasizing its critical role in modulating immune responses during sepsis. Mechanistically, key lactate transporters like MCT1, MCT4, and the receptor GPR81 are crucial in mediating these effects. HIF-1α also plays a significant role in lactate-driven immune modulation. Additionally, lactate affects immune cell function through post-translational modifications such as lactylation, acetylation, and phosphorylation, which alter enzyme activities and protein functions. These interactions between lactate and immune cells are central to understanding sepsis-associated immune dysregulation, offering insights that can guide future research and improve therapeutic strategies to enhance patient outcomes.

Exosome-Derived microRNA: Potential Target for Diagnosis and Treatment of Sepsis

Exosome-derived microRNAs (miRNAs) are emerging as pivotal players in the pathophysiology of sepsis, representing a new frontier in both the diagnosis and treatment of this complex condition. Sepsis, a severe systemic response to infection, involves intricate immune and nonimmune mechanisms, where exosome-mediated communication can significantly influence disease progression and outcomes. During the progress of sepsis, the miRNA profile of exosomes undergoes notable alterations, is reflecting, and may affect the progression of the disease. This review comprehensively explores the biology of exosome-derived miRNAs, which originate from both immune cells (such as macrophages and dendritic cells) and nonimmune cells (such as endothelial and epithelial cells) and play a dynamic role in modulating pathways that affect the course of sepsis, including those related to inflammation, immune response, cell survival, and apoptosis. Taking into account these dynamic changes, we further discuss the potential of exosome-derived miRNAs as biomarkers for the early detection and prognosis of sepsis and advantages over traditional biomarkers due to their stability and specificity. Furthermore, this review evaluates exosome-based therapeutic miRNA delivery systems in sepsis, which may pave the way for targeted modulation of the septic response and personalized treatment options.

Lactate and Lactylation in Sepsis: A Comprehensive Review

Sepsis is a disorder of the immune response to infection or infectious factors with high morbidity and mortality in clinical settings. The lactylation of lysine residues, fueled by lactate, plays a pivotal role in its pathophysiology. In conducting a literature review on sepsis-related research, we employed a systematic approach to ensure comprehensiveness and accuracy. Initially, we conducted an extensive literature search through the PubMed database, utilizing a range of keywords including "sepsis", "lactate", "lactylation", and "epigenetic modification". The aim was to capture the most recent research related to the pathophysiological mechanisms of sepsis, metabolic disorders, and the role of lactylation. The results of the literature review revealed a close link between sepsis and metabolic dysfunction, particularly the pivotal role of lactylation in regulating immune responses and inflammatory processes. Lactate, not only an energy metabolic byproduct produced during glycolysis, affects the activity of various proteins, including those involved in immune regulation and cell signaling, through lactylation. In the context of sepsis, changes in the levels of lactylation may be closely associated with the severity and prognosis of the disease. In summary, lactylation, as an emerging type of epigenetic modification, provides a new perspective for the diagnosis and treatment of sepsis. Future research needs to further elucidate the exact mechanisms of lactylation in sepsis and explore its potential as a therapeutic target.

Dysregulated dendritic cells in sepsis: functional impairment and regulated cell death

Sepsis is defined as life-threatening organ dysfunction caused by a dysregulated host response to infection. Studies have indicated that immune dysfunction plays a central role in the pathogenesis of sepsis. Dendritic cells (DCs) play a crucial role in the emergence of immune dysfunction in sepsis. The major manifestations of DCs in the septic state are abnormal functions and depletion in numbers, which are linked to higher mortality and vulnerability to secondary infections in sepsis. Apoptosis is the most widely studied pathway of number reduction in DCs. In the past few years, there has been a surge in studies focusing on regulated cell death (RCD). This emerging field encompasses various forms of cell death, such as necroptosis, pyroptosis, ferroptosis, and autophagy-dependent cell death (ADCD). Regulation of DC's RCD can serve as a possible therapeutic focus for the treatment of sepsis. Throughout time, numerous tactics have been devised and effectively implemented to improve abnormal immune response during sepsis progression, including modifying the functions of DCs and inhibiting DC cell death. In this review, we provide an overview of the functional impairment and RCD of DCs in septic states. Also, we highlight recent advances in targeting DCs to regulate host immune response following septic challenge.

Effect of ethanol exposure on innate immune response in sepsis

Alcohol use disorder, reported by 1 in 8 critically ill patients, is a risk factor for death in sepsis patients. Sepsis, the leading cause of death, kills over 270,000 patients in the United States alone and remains without targeted therapy. Immune response in sepsis transitions from an early hyperinflammation to persistent inflammation and immunosuppression and multiple organ dysfunction during late sepsis. Innate immunity is the first line of defense against pathogen invasion. Ethanol exposure is known to impair innate and adaptive immune response and bacterial clearance in sepsis patients. Specifically, ethanol exposure is known to modulate every aspect of innate immune response with and without sepsis. Multiple molecular mechanisms are implicated in causing dysregulated immune response in ethanol exposure with sepsis, but targeted treatments have remained elusive. In this article, we outline the effects of ethanol exposure on various innate immune cell types in general and during sepsis.

Sepsis-Related Lung Injury and the Complication of Extrapulmonary Pneumococcal Pneumonia

Globally, sepsis and pneumonia account for significant mortality and morbidity. A complex interplay of immune-molecular pathways underlies both sepsis and pneumonia, resulting in similar and overlapping disease characteristics. Sepsis could result from unmanaged pneumonia. Similarly, sepsis patients have pneumonia as a common complication in the intensive care unit. A significant percentage of pneumonia is misdiagnosed as septic shock. Therefore, our knowledge of the clinical relationship between pneumonia and sepsis is imperative to the proper management of these syndromes. Regarding pathogenesis and etiology, pneumococcus is one of the leading pathogens implicated in both pneumonia and sepsis syndromes. Growing evidence suggests that pneumococcal pneumonia can potentially disseminate and consequently induce systemic inflammation and severe sepsis. Streptococcus pneumoniae could potentially exploit the function of dendritic cells (DCs) to facilitate bacterial dissemination. This highlights the importance of pathogen-immune cell crosstalk in the pathophysiology of sepsis and pneumonia. The role of DCs in pneumococcal infections and sepsis is not well understood. Therefore, studying the immunologic crosstalk between pneumococcus and host immune mediators is crucial to elucidating the pathophysiology of pneumonia-induced lung injury and sepsis. This knowledge would help mitigate clinical diagnosis and management challenges.

The Role of the Intravenous IgA and IgM-Enriched Immunoglobulin Preparation in the Treatment of Sepsis and Septic Shock

Polyclonal Intravenous Immunoglobulins (IvIg) are often administered to critically ill patients more as an act of faith than on the basis of relevant clinical studies. This particularly applies to the treatment of sepsis and septic shock because the current guidelines recommend against their use despite many investigations that have demonstrated their beneficial effects in different subsets of patients. The biology, mechanisms of action, and clinical experience related to the administration of IvIg are reviewed, which aim to give a more in-depth understanding of their properties in order to clarify their possible indications in sepsis and septic shock patients.

PINK1 protects against dendritic cell dysfunction during sepsis through the regulation of mitochondrial quality control

BACKGROUND

Dendritic cell (DC) dysfunction plays a central role in sepsis-induced immunosuppression. Recent research has indicated that collective mitochondrial fragmentation contributes to the dysfunction of immune cells observed during sepsis. PTEN-induced putative kinase 1 (PINK1) has been characterized as a guide for impaired mitochondria that can keep mitochondrial homeostasis. However, its role in the function of DCs during sepsis and the related mechanisms remain obscure. In our study, we elucidated the effect of PINK1 on DC function during sepsis and its underlying mechanism of action.

METHODS

Cecal ligation and puncture (CLP) surgery and lipopolysaccharide (LPS) treatment were used as in vivo and in vitro sepsis models, respectively.

RESULTS

We found that changes in mitochondrial PINK1 expression of DCs paralleled changes in DC function during sepsis. The ratio of DCs expressing MHC-II, CD86, and CD80, the mRNAs level of dendritic cells expressing TNF-α and IL-12, and the level of DC-mediated T-cell proliferation were all decreased, both in vivo and in vitro during sepsis, when PINK1 was knocked out. This suggested that PINK1 knockout prevented the function of DCs during sepsis. Furthermore, PINK1 knockout inhibited Parkin RBR E3 ubiquitin protein (Parkin)-dependent mitophagy and enhanced dynamin-related protein 1 (Drp1)-related mitochondrial fission, and the negative effects of PINK1 knockout on DC function following LPS treatment were reversed by Parkin activation and Drp1 inhibitor. Knockout of PINK1 also increased apoptosis of DCs and the mortality of CLP mice.

CONCLUSION

Our results indicated that PINK1 protected against DC dysfunction during sepsis through the regulation of mitochondrial quality control.

Redox regulation of the immune response

The immune-inflammatory response is associated with increased nitro-oxidative stress. The aim of this mechanistic review is to examine: (a) the role of redox-sensitive transcription factors and enzymes, ROS/RNS production, and the activity of cellular antioxidants in the activation and performance of macrophages, dendritic cells, neutrophils, T-cells, B-cells, and natural killer cells; (b) the involvement of high-density lipoprotein (HDL), apolipoprotein A1 (ApoA1), paraoxonase-1 (PON1), and oxidized phospholipids in regulating the immune response; and (c) the detrimental effects of hypernitrosylation and chronic nitro-oxidative stress on the immune response. The redox changes during immune-inflammatory responses are orchestrated by the actions of nuclear factor-κB, HIF1α, the mechanistic target of rapamycin, the phosphatidylinositol 3-kinase/protein kinase B signaling pathway, mitogen-activated protein kinases, 5' AMP-activated protein kinase, and peroxisome proliferator-activated receptor. The performance and survival of individual immune cells is under redox control and depends on intracellular and extracellular levels of ROS/RNS. They are heavily influenced by cellular antioxidants including the glutathione and thioredoxin systems, nuclear factor erythroid 2-related factor 2, and the HDL/ApoA1/PON1 complex. Chronic nitro-oxidative stress and hypernitrosylation inhibit the activity of those antioxidant systems, the tricarboxylic acid cycle, mitochondrial functions, and the metabolism of immune cells. In conclusion, redox-associated mechanisms modulate metabolic reprogramming of immune cells, macrophage and T helper cell polarization, phagocytosis, production of pro- versus anti-inflammatory cytokines, immune training and tolerance, chemotaxis, pathogen sensing, antiviral and antibacterial effects, Toll-like receptor activity, and endotoxin tolerance.

TNF-α-induced protein 8-like 2 negatively regulates the immune function of dendritic cells by suppressing autophagy via the TAK1/JNK pathway in septic mice

Tumor necrosis factor (TNF)-α-induced protein 8-like 2 (TIPE2) is a newly discovered negative immunoregulatory protein that is involved in various cellular immune responses to infections. However, the underlying mechanism by which TIPE2 affects the immune function of dendritic cells (DCs) is not yet understood. This study aimed to determine the correlations among DCs TIPE2 expression, autophagic activity and immune function in the context of sepsis. In addition, the signaling pathway by which TIPE2 regulates autophagy in DCs was investigated. We reported for the first time that TIPE2 overexpression (knock-in, KI) exerted an inhibitory effect on autophagy in DCs and markedly suppressed the immune function of DCs upon septic challenge both in vitro and in vivo. In addition, TIPE2 knockout (KO) in DCs significantly enhanced autophagy and improved the immune response of DCs in sepsis. Of note, we found that the transforming growth factor-β (TGF-β)-activated kinase-1 (TAK1)/c-Jun N-terminal kinase (JNK) pathway was inhibited by TIPE2 in DCs, resulting in downregulated autophagic activity. Collectively, these results suggest that TIPE2 can suppress the autophagic activity of DCs by inhibiting the TAK1/JNK signaling pathway and further negatively regulate the immune function of DCs in the development of septic complications.

Sestrin2 protects dendrite cells against ferroptosis induced by sepsis

Ferroptosis is a nonapoptotic form of programmed cell death triggered by the accumulation of reactive oxygen species (ROS) depended on iron overload. Although most investigations focus on the relationship between ferroptosis and cancer, neurodegenerative diseases, and ischemia/reperfusion injury, research on ferroptosis induced by immune-related inflammatory diseases, especially sepsis, is scarce. Sestrin2 (Sesn2), a highly evolutionary and stress-responsive protein, is critically involved in defense against oxidative stress challenges. Upregulated expression of Sesn2 has been observed in preliminary experiments to have an antioxidative function in the context of an inflammatory response. Nevertheless, the underlying function of Sesn2 in inflammation-mediated ferroptosis in the immune system remains uncertain. The current study aimed to demonstrate the protective effect of Sesn2 on ferroptosis and even correlations with ferroptosis and the functions of ferroptotic-dendritic cells (DCs) stimulated with lipopolysaccharide (LPS). The mechanism underlying DCs protection from LPS-induced ferroptosis by Sesn2 was further explored in this study. We found that the immune response of DCs assessed by co-stimulatory phenotypes was gradually enhanced at the peak time of 12 h upon 1 μg/ml LPS stimulation while ferroptosis in DCs treated with LPS at 24 h was significantly detected. LPS-induced ferroptosis showed a suppressive impact on DCs in phenotypic maturation, which was conversely relieved by the ferroptotic inhibitor. Compared with wild-type (WT) mice, DCs in genetic defective mice of Sesn2 (Sesn2-/-) exhibited exacerbated ferroptosis. Furthermore, the protective effect of Sesn2 on ferroptosis was noticed to be associated with the ATF4-CHOP-CHAC1 pathway, eventually exacerbating ferroptosis by degrading of glutathione. These results indicate that Sesn2 can suppress the ferroptosis of DCs in sepsis by downregulating the ATF4-CHOP-CHAC1 signaling pathway, and it might play an antioxidative role.

Astaxanthin Protects Dendritic Cells from Lipopolysaccharide-Induced Immune Dysfunction

Astaxanthin, originating from seafood, is a naturally occurring red carotenoid pigment. Previous studies have focused on its antioxidant properties; however, whether astaxanthin possesses a desired anti-inflammatory characteristic to regulate the dendritic cells (DCs) for sepsis therapy remains unknown. Here, we explored the effects of astaxanthin on the immune functions of murine DCs. Our results showed that astaxanthin reduced the expressions of LPS-induced inflammatory cytokines (TNF-α, IL-6, and IL-10) and phenotypic markers (MHCII, CD40, CD80, and CD86) by DCs. Moreover, astaxanthin promoted the endocytosis levels in LPS-treated DCs, and hindered the LPS-induced migration of DCs via downregulating CCR7 expression, and then abrogated allogeneic T cell proliferation. Furthermore, we found that astaxanthin inhibited the immune dysfunction of DCs induced by LPS via the activation of the HO-1/Nrf2 axis. Finally, astaxanthin with oral administration remarkably enhanced the survival rate of LPS-challenged mice. These data showed a new approach of astaxanthin for potential sepsis treatment through avoiding the immune dysfunction of DCs.

Sepsis-Pathophysiology and Therapeutic Concepts

Sepsis is a life-threatening condition and a global disease burden. Today, the heterogeneous syndrome is defined as severe organ dysfunction caused by a dysregulated host response to infection, with renewed emphasis on immune pathophysiology. Despite all efforts of experimental and clinical research during the last three decades, the ability to positively influence course and outcome of the syndrome remains limited. Evidence-based therapy still consists of basic causal and supportive measures, while adjuvant interventions such as blood purification or targeted immunotherapy largely remain without proof of effectiveness so far. With this review, we aim to provide an overview of sepsis immune pathophysiology, to update the choice of therapeutic approaches targeting different immunological mechanisms in the course of sepsis and septic shock, and to call for a paradigm shift from the pathogen to the host response as a potentially more promising angle.

BRG1 Links TLR4 Trans-Activation to LPS-Induced SREBP1a Expression and Liver Injury

Multiple organ failure is one of the most severe consequences in patients with septic shock. Liver injury is frequently observed during this pathophysiological process. In the present study we investigated the contribution of Brahma related gene 1 (BRG1), a chromatin remodeling protein, to septic shock induced liver injury. When wild type (WT) and liver conditional BRG1 knockout (LKO) mice were injected with lipopolysaccharide (LPS), liver injury was appreciably attenuated in the LKO mice compared to the WT mice as evidenced by plasma ALT/AST levels, hepatic inflammation and apoptosis. Of interest, there was a down-regulation of sterol response element binding protein 1a (SREBP1a), known to promote liver injury, in the LKO livers compared to the WT livers. BRG1 did not directly bind to the SREBP1a promoter. Instead, BRG1 was recruited to the toll-like receptor 4 (TLR4) promoter and activated TLR4 transcription. Ectopic TLR4 restored SREBP1a expression in BRG1-null hepatocytes. Congruently, adenovirus carrying TLR4 or SREBP1a expression vector normalized liver injury in BRG1 LKO mice injected with LPS. Finally, a positive correlation between BRG1 and TLR4 expression was detected in human liver biopsy specimens. In conclusion, our data demonstrate that a BRG1-TLR4-SREBP1a axis that mediates LPS-induced liver injury in mice.

Sepsis and Septic Shock; Current Treatment Dilemma and Role of Stem Cell Therapy in Pediatrics

Context: Sepsis’s primary therapy consists of antibiotics therapy, supportive therapies, and source control of infection. The failure rate of this approach is about 20 - 40%. The widespread use of antibiotics has caused multiple drug resistance in primary etiological agents of sepsis in community-acquired and healthcare-associated infections. In the absence of new antibiotic options, alternative treatment modalities seem necessary. Evidence Acquisition: Herein, we have reviewed and discussed current problems with sepsis management and stem cell therapy in sepsis, preclinical, experimental studies, and early-phase clinical trials using stem cells to treat sepsis. In the preparation of the paper, PubMed, Web of Science Core Collection (Clarivate), Scopus, and the web address (www.clinicaltrials.gov) were searched by the keywords (sepsis and cell therapy, septic shock, and cell therapy). Results: After the inclusion of criteria, we reviewed 301 original articles. Few articles were found for phase II and phase III clinical trials. Eighty-three articles were included in the current review article. Besides problems with infection source control, the host immune response to the infection enumerated for primary underlying pathophysiologic dysregulation of sepsis and complicated the treatment. Mesenchymal stem cells (MSCs) therapy offers a promising treatment option for sepsis. Indeed, immunomodulatory properties, antimicrobial activity, the capacity of protection against organ failure, enhance the resolution of tissue injury, tissue repair, and restoration after sepsis confer MSCs with a significant advantage to treat the immune and inflammatory dysfunctions associated with severe sepsis and septic shock. Conclusions: It seems that MSCs therapy exhibits an appropriate safety index. Future trials should focus on strengthening study quality, reporting MSCs’ therapeutic effects and adverse events. Although early clinical trials seem promising and have beneficial effects, we need more controlled clinical studies, especially in phases II and III.

Best-practice IgM- and IgA-enriched immunoglobulin use in patients with sepsis

Background

Sepsis is a life-threatening organ dysfunction caused by a dysregulated host response to infection. Despite treatment being in line with current guidelines, mortality remains high in those with septic shock. Intravenous immunoglobulins represent a promising therapy to modulate both the pro- and anti-inflammatory processes and can contribute to the elimination of pathogens. In this context, there is evidence of the benefits of immunoglobulin M (IgM)- and immunoglobulin A (IgA)-enriched immunoglobulin therapy for sepsis. This manuscript aims to summarize current relevant data to provide expert opinions on best practice for the use of an IgM- and IgA-enriched immunoglobulin (Pentaglobin) in adult patients with sepsis.

Main text

Sepsis patients with hyperinflammation and patients with immunosuppression may benefit most from treatment with IgM- and IgA-enriched immunoglobulin (Pentaglobin). Patients with hyperinflammation present with phenotypes that manifest throughout the body, whilst the clinical characteristics of immunosuppression are less clear. Potential biomarkers for hyperinflammation include elevated procalcitonin, interleukin-6, endotoxin activity and C-reactive protein, although thresholds for these are not well-defined. Convenient biomarkers for identifying patients in a stage of immune-paralysis are still matter of debate, though human leukocyte antigen–antigen D related expression on monocytes, lymphocyte count and viral reactivation have been proposed. The timing of treatment is potentially more critical for treatment efficacy in patients with hyperinflammation compared with patients who are in an immunosuppressed stage. Due to the lack of evidence, definitive dosage recommendations for either population cannot be made, though we suggest that patients with hyperinflammation should receive an initial bolus at a rate of up to 0.6 mL (30 mg)/kg/h for 6 h followed by a continuous maintenance rate of 0.2 mL (10 mg)/kg/hour for ≥ 72 h (total dose ≥ 0.9 g/kg). For immunosuppressed patients, dosage is more conservative (0.2 mL [10 mg]/kg/h) for ≥ 72 h, without an initial bolus (total dose ≥ 0.72 g/kg).

Conclusions

Two distinct populations that may benefit most from Pentaglobin therapy are described in this review. However, further clinical evidence is required to strengthen support for the recommendations given here regarding timing, duration and dosage of treatment.

Study of thermo-regulation as a worsening marker of experimental sepsis in an animal model

Objective:

to analyze variations in body temperature and in plasma nitrate and lactate concentrations in rats submitted to the experimental sepsis model.

Method:

a total of 40 rats divided equally into five groups. The induction of endotoxemia was performed with intravenous administration of lipopolysaccharide, 0.5 mg/Kg, 1.5 mg/Kg, 3.0 mg/Kg, and 10 mg/Kg, respectively. The control group received 0.5 mL of saline solution. The experiment lasted six hours, with evaluations performed at 0 (baseline data), 2^nd, 4^th, and 6^thhours.

Results:

The animals that received doses up to 3.0 mg/kg showed a significant increase in body temperature compared to the group with 10 mg/kg, which showed a decrease in these values. The increase in plasma nitrate and lactate concentrations in the groups with lipopolysaccharide was significantly higher than in the group that received the saline solution and was correlated with the increase in body temperature.

Conclusion:

the variations in body temperature observed in this study showed the dose-dependent effect of lipopolysaccharide and were correlated with the increase in the concentrations of nitrate and plasma lactate biomarkers. The implications of this study are the importance of monitoring body temperature, together with the assessment of these pathophysiological markers, which suggest worsening in the prognosis of sepsis.

Use of Intravenous Immunoglobulins in Sepsis Therapy-A Clinical View

Sepsis is a life-threatening organ dysfunction, defined by a dysregulated host immune response to infection. During sepsis, the finely tuned system of immunity, inflammation and anti-inflammation is disturbed in a variety of ways. Both pro-inflammatory and anti-inflammatory pathways are upregulated, activation of the coagulation cascade and complement and sepsis-induced lymphopenia occur. Due to the manifold interactions in this network, the use of IgM-enriched intravenous immunoglobulins seems to be a promising therapeutic approach. Unfortunately, there is still a lack of evidence-based data to answer the important questions of appropriate patient populations, optimal timing and dosage of intravenous immunoglobulins. With this review, we aim to provide an overview of the role of immunoglobulins, with emphasis on IgM-enriched formulations, in the therapy of adult patients with sepsis and septic shock.

Activation of α7 Nicotinic Acetylcholine Receptor Upregulates HLA-DR and Macrophage Receptors: Potential Role in Adaptive Immunity and in Preventing Immunosuppression

Immune response during sepsis is characterized by hyper-inflammation followed by immunosuppression. The crucial role of macrophages is well-known for both septic stages, since they are involved in immune homeostasis and inflammation, their dysfunction being implicated in immunosuppression. The cholinergic anti-inflammatory pathway mediated by macrophage α7 nicotinic acetylcholine receptor (nAChR) represents possible drug target. Although α7 nAChR activation on macrophages reduces the production of proinflammatory cytokines, the role of these receptors in immunological changes at the cellular level is not fully understood. Using α7 nAChR selective agonist PNU 282,987, we investigated the influence of α7 nAChR activation on the expression of cytokines and, for the first time, of the macrophage membrane markers: cluster of differentiation 14 (CD14), human leukocyte antigen-DR (HLA-DR), CD11b, and CD54. Application of PNU 282,987 to THP-1Mϕ (THP-1 derived macrophages) cells led to inward ion currents and Ca2+ increase in cytoplasm showing the presence of functionally active α7 nAChR. Production of cytokines tumor necrosis factor-α (TNF-α), interleukin (IL)-6, and IL-10 was estimated in classically activated macrophages (M1) and treatment with PNU 282,987 diminished IL-10 expression. α7 nAChR activation on THP-1Mϕ, THP-1M1, and monocyte-derived macrophages (MDMs) increased the expression of HLA-DR, CD54, and CD11b molecules, but decreased CD14 receptor expression, these effects being blocked by alpha (α)-bungarotoxin. Thus, PNU 282,987 enhances the macrophage-mediated immunity via α7 nAChR by regulating expression of their membrane receptors and of cytokines, both playing an important role in preventing immunosuppressive states.

Crosstalk between Dendritic Cells and Immune Modulatory Agents against Sepsis

Dendritic cells (DCs) play a critical role in the immune system which sense pathogens and present their antigens to prime the adaptive immune responses. As the progression of sepsis occurs, DCs are capable of orchestrating the aberrant innate immune response by sustaining the Th1/Th2 responses that are essential for host survival. Hence, an in-depth understanding of the characteristics of DCs would have a beneficial effect in overcoming the obstacle occurring in sepsis. This paper focuses on the role of DCs in the progression of sepsis and we also discuss the reverse sepsis-induced immunosuppression through manipulating the DC function. In addition, we highlight some potent immunotherapies that could be used as a novel strategy in the early treatment of sepsis.

Sepsis-associated encephalopathy: a vicious cycle of immunosuppression

Sepsis-associated encephalopathy (SAE) is commonly complicated by septic conditions, and is responsible for increased mortality and poor outcomes in septic patients. Uncontrolled neuroinflammation and ischemic injury are major contributors to brain dysfunction, which arises from intractable immune malfunction and the collapse of neuroendocrine immune networks, such as the cholinergic anti-inflammatory pathway, hypothalamic-pituitary-adrenal axis, and sympathetic nervous system. Dysfunction in these neuromodulatory mechanisms compromised by SAE jeopardizes systemic immune responses, including those of neutrophils, macrophages/monocytes, dendritic cells, and T lymphocytes, which ultimately results in a vicious cycle between brain injury and a progressively aberrant immune response. Deep insight into the crosstalk between SAE and peripheral immunity is of great importance in extending the knowledge of the pathogenesis and development of sepsis-induced immunosuppression, as well as in exploring its effective remedies.

Pathological alteration and therapeutic implications of sepsis-induced immune cell apoptosis

Sepsis is a life-threatening organ dysfunction syndrome caused by dysregulated host response to infection that leads to uncontrolled inflammatory response followed by immunosuppression. However, despite the high mortality rate, no specific treatment modality or drugs with high efficacy is available for sepsis to date. Although improved treatment strategies have increased the survival rate during the initial state of excessive inflammatory response, recent trends in sepsis show that mortality occurs at a period of continuous immunosuppressive state in which patients succumb to secondary infections within a few weeks or months due to post-sepsis “immune paralysis.” Immune cell alteration induced by uncontrolled apoptosis has been considered a major cause of significant immunosuppression. Particularly, apoptosis of lymphocytes, including innate immune cells and adaptive immune cells, is associated with a higher risk of secondary infections and poor outcomes. Multiple postmortem studies have confirmed that sepsis-induced immune cell apoptosis occurs in all age groups, including neonates, pediatric, and adult patients, and it is considered to be a primary contributing factor to the immunosuppressive pathophysiology of sepsis. Therapeutic perspectives targeting apoptosis through various strategies could improve survival in sepsis. In this review article, we will focus on describing the major apoptosis process of immune cells with respect to physiologic and molecular mechanisms. Further, advances in apoptosis-targeted treatment modalities for sepsis will also be discussed.

Lactate and Immunosuppression in Sepsis

Serum lactate levels are traditionally interpreted as a marker of tissue hypoxia and often used clinically as an indicator of severity and outcome of sepsis/septic shock. Interestingly, recent studies involving the effects of tumor-derived lactate suggest that lactate itself may have an immunosuppressive effect in its local environment. This finding adds to the recent advances in immunometabolism that shed light on the importance of metabolism and metabolic intermediates in the regulation of innate immune and inflammatory responses in sepsis. In this article, we summarize recent studies, showing that the activation of immune cells requires aerobic glycolytic metabolism and that lactate produced by aerobic glycolysis may play an immunosuppressive role in sepsis.

Experimental hypercoagulable state induced by tissue factor expression in monocyte-derived dendritic cells and its modulation by C1 inhibitor

The crosstalk between immune and coagulation systems plays pivotal roles in host defense, which may involve monocyte-derived dendritic cells (moDCs). Our objectives were to elucidate the role of moDCs in coagulation under inflammatory conditions and the involvement of the complement system. We assessed the effects of lipopolysaccharide (LPS)-stimulated moDCs on coagulation using whole blood thromboelastometry in the presence of complement inhibitors. The sum of clotting time and clot formation time (CT plus CFT) in whole blood thromboelastometry was significantly more reduced in the presence of moDCs than in the absence of monocytes or moDCs and in the presence of monocytes, indicating a more potent coagulability of moDCs. The mRNA expression of coagulation-related proteins in moDCs was analyzed by quantitative PCR, which showed an increase only in the mRNA levels of tissue factor (TF). TF protein expression was assessed by western blot analysis and an activity assay, revealing higher TF expression in moDCs than that in monocytes. The in vitro moDC-associated hypercoagulable state was suppressed by a TF-neutralizing antibody, whereas LPS enhanced the in vitro hypercoagulation further. C1 inhibitor suppressed the in vitro LPS-enhanced whole blood hypercoagulability in the presence of moDCs and the increased TF expression in moDCs. These results suggest a significant role of moDCs and the complement system through TF expression in a hypercoagulable state under inflammatory conditions and demonstrate the suppressive effects of C1 inhibitor on moDC-associated hypercoagulation.

Endotoxin Tolerant Dendritic Cells Suppress Inflammatory Responses in Splenocytes via Interleukin-1 Receptor Associated Kinase (IRAK)-M and Programmed Death-Ligand 1 (PDL-1)

BACKGROUND Sepsis causes the highest mortality in non-cardiovascular intensive care units worldwide. Recent research has demonstrated that the late phase of sepsis, characterized as septic immunosuppression, is the central pathophysiological mechanism of immune dysfunction. Investigating the suppressive mechanism of immune cells may identify possible targets for therapy. MATERIAL AND METHODS We used LPS 2-hit model for dendritic cells (DCs) to establish endotoxin tolerance, and co-cultured with splenocytes. Co-culture responses and gene expressions were evaluated. RESULTS Endotoxin tolerant DCs showed irresponsiveness in pro-inflammatory cytokine production and expressed negative regulator genes of inflammation. When co-cultured with splenocytes, suppression of inflammatory responses and T cells apoptosis were observed with elevated expression of IRAK-M and PDL-1, and interference and neutralization of these 2 molecules led to partly reversed suppression of inflammation. CONCLUSIONS Our research found direct regulation of endotoxin tolerant DCs to other immune cells and suggested a possible mechanism via IRAK-M and PDL-1. This may inform research on septic immunosuppression and suggests possible therapeutic targets for sepsis.

Toll-like receptors in immunity and inflammatory diseases: Past, present, and future

The immune system is a very diverse system of the host that evolved during evolution to cope with various pathogens present in the vicinity of environmental surroundings inhabited by multicellular organisms ranging from achordates to chordates (including humans). For example, cells of immune system express various pattern recognition receptors (PRRs) that detect danger via recognizing specific pathogen-associated molecular patterns (PAMPs) and mount a specific immune response. Toll-like receptors (TLRs) are one of these PRRs expressed by various immune cells. However, they were first discovered in the Drosophila melanogaster (common fruit fly) as genes/proteins important in embryonic development and dorso-ventral body patterning/polarity. Till date, 13 different types of TLRs (TLR1-TLR13) have been discovered and described in mammals since the first discovery of TLR4 in humans in late 1997. This discovery of TLR4 in humans revolutionized the field of innate immunity and thus the immunology and host-pathogen interaction. Since then TLRs are found to be expressed on various immune cells and have been targeted for therapeutic drug development for various infectious and inflammatory diseases including cancer. Even, Single nucleotide polymorphisms (SNPs) among various TLR genes have been identified among the different human population and their association with susceptibility/resistance to certain infections and other inflammatory diseases. Thus, in the present review the current and future importance of TLRs in immunity, their pattern of expression among various immune cells along with TLR based therapeutic approach is reviewed.

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TLRs are first described PRRs that revolutionized the biology of host-pathogen interaction and immune response

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The discovery of different TLRs in humans proved milestone in the field of innate immunity and inflammation

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The pattern of expression of all the TLRs expressed by human immune cells

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An association of various TLR SNPs with different inflammatory diseases

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Currently available drugs or vaccines based on TLRs and their future in drug targeting along with the role in reproduction, and regeneration

Autophagy: A Potential Therapeutic Target for Reversing Sepsis-Induced Immunosuppression

Sepsis remains the leading cause of mortality in intensive care units and an intractable condition due to uncontrolled inflammation together with immune suppression. Dysfunction of immune cells is considered as a major cause for poor outcome of septic patients but with little specific treatments. Currently, autophagy that is recognized as an important self-protective mechanism for cellular survival exhibits great potential for maintaining immune homeostasis and alleviating multiple organ failure, which further improves survival of septic animals. The protective effect of autophagy on immune cells covers both innate and adaptive immune responses and refers to various cellular receptors and intracellular signaling. Multiple drugs and measures are reportedly beneficial for septic challenge by inducing autophagy process. Therefore, autophagy might be an effective target for reversing immunosuppression compromised by sepsis.

Dendritic cells in the regulation of immunity and inflammation

As potent antigen-presenting cells, dendritic cells (DCs) comprise the most heterogeneous cell population with significant cellular phenotypic and functional plasticity. They form a sentinel network to modulate immune responses, since intrinsic cellular mechanisms and complex external, environmental signals endow DCs with the distinct capacity to induce protective immunity or tolerance to self. Interactions between DCs and other cells of the immune system mediate this response. This interactive response depends on DC maturation status and subtype, as well as the microenvironment of the tissue location and DC-intrinsic regulators. Dysregulated DCs can initiate and perpetuate various immune disorders, which creates attractive therapeutic targets. In this review, we provide a detailed outlook on DC ontogeny and functional specialization. We highlight recent advances on the regulatory role that DCs play in immune responses, the putative molecular regulators that control DC functional responding and the contribution of DCs to inflammatory disease physiopathology.

Dendritic Cells in Sepsis: Pathological Alterations and Therapeutic Implications

Sepsis is the leading cause of death for critically ill patients in recent years. Dendritic cells (DCs) are important antigen-presenting cells and play a key role in immune response by regulating the innate and adaptive immunity. The number of DCs, the differentiation of monocytes into DCs, and the levels of surface molecules associated with the function of DCs are changed in the development of sepsis. There are many mechanisms involved in the alterations of DCs during sepsis, including the induction of apoptosis, reactive oxygen species generation, activation of the Wnt signaling pathway, epigenetic regulation, and variation in Toll-like receptor-dependent signaling. In this review, we present the classifications of DC subsets and mechanisms involved in the alterations of DCs in sepsis, as well as further discuss the therapeutic strategies targeting DCs in sepsis to improve the aberrant immune response and prolong the life during sepsis progression.

Therapeutic targeting of HMGB1 during experimental sepsis modulates the inflammatory cytokine profile to one associated with improved clinical outcomes

Sepsis remains a significant health burden and a major clinical need exists for therapeutics to dampen the excessive and uncontrolled immune activation. Nuclear protein high mobility group box protein 1 (HMGB1) is released following cell death and is a late mediator in sepsis pathogenesis. While approaches targeting HMGB1 have demonstrated reduced mortality in pre-clinical models of sepsis, the impact of HMGB1 blockade on the complex septic inflammatory milieu and the development of subsequent immunosuppression remain enigmatic. Analysis of plasma samples obtained from septic shock patients established an association between increased HMGB1 and non-survival, higher APACHE II scores, and increased pro-inflammatory cytokine responses. Pre-clinically, administration of neutralising ovine anti-HMGB1 polyclonal antibodies improved survival in murine endotoxaemia and caecal ligation and puncture-induced sepsis models, and altered early cytokine profiles to one which corresponded to patterns observed in the surviving patient cohort. Additionally, anti-HMGB1 treated murine sepsis survivors were significantly more resistant to secondary bacterial infection and exhibited altered innate immune cell phenotypes and cytokine responses. These findings demonstrate that anti-HMGB1 antibodies alter inflammation in murine sepsis models and reduce sepsis mortality without potentiating immunosuppression.

The Role of IFN-β during the Course of Sepsis Progression and Its Therapeutic Potential

Sepsis is a complex biphasic syndrome characterized by both pro- and anti-inflammatory immune states. Whereas early sepsis mortality is caused by an acute, deleterious pro-inflammatory response, the second sepsis phase is governed by acute immunosuppression, which predisposes patients to long-term risk for life-threatening secondary infections. Despite extensive basic research and clinical trials, there is to date no specific therapy for sepsis, and mortality rates are on the rise. Although IFN-β is one of the most-studied cytokines, its diverse effects are not fully understood. Depending on the disease or type of infection, it can have beneficial or detrimental effects. As IFN-β has been used successfully to treat diverse diseases, emphasis has been placed on understanding the role of IFN-β in sepsis. Analyses of mouse models of septic shock attribute a pro-inflammatory role to IFN-β in sepsis development. As anti-inflammatory treatments in humans with antibodies to TNF-α or IL1-β resulted disappointing, cytokine modulation approaches were discouraged and neutralization of IFN-β has not been pursued for sepsis treatment. In the case of patients with delayed sepsis and immunosuppression, there is a debate as to whether the use of specific cytokines would restore the deactivated immune response. Recent reports show an association of low IFN-β levels with the hyporesponsive state of monocytes from sepsis patients and after endotoxin tolerance induction. These data, discussed here, project a role for IFN-β in restoring monocyte function and reversing immunosuppression, and suggest IFN-β-based additive immunomodulatory therapy. The dichotomy in putative therapeutic approaches, involving reduction or an increase in IFN-β levels, mirrors the contrasting nature of the early hyperinflammatory state and the delayed immunosuppression phase.

Murine Cytomegalovirus Disrupts Splenic Dendritic Cell Subsets via Type I Interferon-Dependent and -Independent Mechanisms

Dendritic cells (DC) are well-known modulators of immunity. This heterogeneous population is composed of defined subsets that exhibit functional specialization and are critical in initiating responses to pathogens. As such, many infectious agents employ strategies to disrupt DC functioning in attempts to evade the immune system. In some instances, this manifests as an outright loss of these cells. Previous work has suggested that, in the absence of an efficient natural killer (NK) cell response, murine cytomegalovirus (MCMV) induces large amounts of interferon (IFN)-I. This heightened IFN-I response is thought to contribute to conventional DC (cDC) loss and delayed development of T cell immunity. However, the precise role of IFN-I in such cDC loss remains unclear. We investigated the effects of licensed NK cells and IFN-I signaling on splenic cDC subsets during MCMV infection and found that a licensed NK cell response partially protects cDC numbers, but does not prevent increases in serum IFN-I. This suggested that high residual IFN-I could contribute to cDC loss. Therefore, we used multiple strategies to modulate IFN-I signaling during MCMV infection including plasmacytoid DC depletion, IFN-I receptor (IFNAR) blockade, and genetic ablation of IFNAR expression. Interestingly, restriction of IFN-I signals did not substantially preserve either CD8⁺ or CD4⁺ DC total numbers, but resulted in significant retention and/or accumulation of the splenic CD8⁻ CD4⁻ [double negative (DN)] subset. However, the DN DC effect manifested in a DC-extrinsic manner since IFNAR-deficient cells were not preferentially retained over their IFNAR wild-type counterparts in a mixed-chimera setting. Our results show that IFN-I signaling is not responsible for overt cDC toxicity in the setting of acute MCMV infection and emphasize that additional mechanisms contribute to DC loss and require exploration.

The role of porcine reproductive and respiratory syndrome virus infection in immune phenotype and Th1/Th2 balance of dendritic cells

The aim of this study was to characterize the immune response of dendritic cells derived from monocytes (Mo-DCs) in the porcine peripheral blood following infection with porcine reproductive and respiratory syndrome virus (PRRSV). Viral load assays indicated that PRRSV efficiently infected Mo-DCs but failed to replicate, whereas PRRSV infection of Mo-DCs decreased the expression of SLA-I, SLA-II, CD80 and CD40 compared with those of mock Mo-DCs. Furthermore, we analyzed the cytokine profiles using quantitative RT-PCR and ELISA. Results indicated apparent changes in IL-10 and IL-12 p40 expression but not in IFN-γ and TNF-α among Mo-DCs infected with PRRSV and uninfected Mo-DCs. Additionally, flow cytometry analysis of the altered Mo-DCs together with IL-4 and GM-CSF induction for 7days revealed the typical morphology and phenotype with 91.73% purity before infection with PRRSV. Overall, our data demonstrate that PRRSV impaired the normal antigen presentation of Mo-DCs and led to inadequate adaptive immune response by down-regulating the expression of SLA-I,SLA-II, CD80 and CD40. Enhanced Th2 -type cytokine IL-10 secretion and reduced Th1-type cytokines IL-12p40,IFN-γ and TNF-α secretion results in Th1/Th2 imbalance.

Immunotherapy: A promising approach to reverse sepsis-induced immunosuppression

Sepsis is defined as life-threatening organ dysfunction caused by dysregulated host responses to infection (Third International Consensus definition for Sepsis and septic shock). Despite decades of research, sepsis remains the leading cause of death in intensive care units. More than 40 clinical trials, most of which have targeted the sepsis-associated pro-inflammatory response, have failed. Thus, antibiotics and fluid resuscitation remain the mainstays of supportive care and there is intense need to discover and develop novel, targeted therapies to treat sepsis. Both pre-clinical and clinical studies over the past decade demonstrate unequivocally that sepsis not only causes hyper-inflammation, but also leads to simultaneous adaptive immune system dysfunction and impaired antimicrobial immunity. Evidences for immunosuppression include immune cell depletion (T cells most affected), compromised T cell effector functions, T cell exhaustion, impaired antigen presentation, increased susceptibility to opportunistic nosocomial infections, dysregulated cytokine secretion, and reactivation of latent viruses. Therefore, targeting immunosuppression provides a logical approach to treat protracted sepsis. Numerous pre-clinical studies using immunomodulatory agents such as interleukin-7, anti-programmed cell death 1 antibody (anti-PD-1), anti-programmed cell death 1 ligand antibody (anti-PD-L1), and others have demonstrated reversal of T cell dysfunction and improved survival. Therefore, identifying immunosuppressed patients with the help of specific biomarkers and administering specific immunomodulators holds significant potential for sepsis therapy in the future. This review focusses on T cell dysfunction during sepsis and discusses the potential immunotherapeutic agents to boost T cell function during sepsis and improve host resistance to infection.

Paeonol protects endotoxin-induced acute kidney injury: potential mechanism of inhibiting TLR4-NF-κB signal pathway

STUDY DESIGN AND METHODS

In order to determine the therapeutic effect and mechanism of paeonol on acute kidney injury induced by endotoxin, an acute kidney injury model was established by intraperitoneal administration of lipopolysaccharide in mice in vivo and on LPS-induced dendritic cells in vitro. Renal tissues were used for histologic examination. Concentrations of blood urea nitrogen and serum creatinine were detected, inflammatory cytokines were determined by ELISA. The relative proteins' expression of TLR4-NF-κB signal pathway was assessed by Western blot, the localization and expression of phospho-NF-κB p65 in kidney was monitored by immunohistochemistry.

RESULTS

Treatment of paeonol successfully cuts histopathological scores and dilutes the concentrations of blood urea nitrogen and serum creatinine as index of renal injury severity. In addition, paeonol reduces pro-inflammatory cytokines and increases anti-inflammatory cytokines stimulated by LPS in a dose-dependent manner. Paeonol also inhibits the expression of phosphorylated NF-κB p65, IκBα and IKKβ, and restrains NF-κB p65 DNA-binding activity. Paeonol treatment also attenuates the effects of LPS on dendritic cells, with significant inhibition of pro-inflammatory cytokines release, then TLR4 expression and NF-κB signal pathway have been suppressed.

CONCLUSIONS

These results indicated that paeonol has protective effects on endotoxin-induced kidney injury. The mechanisms underlying such effects are associated with its successfully attenuate inflammatory and suppresses TLR4 and NF-κB signal pathway. Therefore, paeonol has great potential to be a novel and natural product agent for treating AKI or septic-AKI.

Defining immunological dysfunction in sepsis: A requisite tool for precision medicine

OBJECTIVES

Immunological dysregulation is now recognised as a major pathogenic event in sepsis. Stimulation of immune response and immuno-modulation are emerging approaches for the treatment of this disease. Defining the underlying immunological alterations in sepsis is important for the design of future therapies with immuno-modulatory drugs.

METHODS

Clinical studies evaluating the immunological response in adult patients with Sepsis and published in PubMed were reviewed to identify features of immunological dysfunction. For this study we used key words related with innate and adaptive immunity.

RESULTS

Ten major features of immunological dysfunction (FID) were identified involving quantitative and qualitative alterations of [antigen presentation](FID1), [T and B lymphocytes] (FID2), [natural killer cells] (FID3), [relative increase in T regulatory cells] (FID4), [increased expression of PD-1 and PD-ligand1](FID5), [low levels of immunoglobulins](FID6), [low circulating counts of neutrophils and/or increased immature forms in non survivors](FID7), [hyper-cytokinemia] (FID8), [complement consumption] (FID9), [defective bacterial killing by neutrophil extracellular traps](FID10).

CONCLUSIONS

This review article identified ten major features associated with immunosuppression and immunological dysregulation in sepsis. Assessment of these features could help in utilizing precision medicine for the treatment of sepsis with immuno-modulatory drugs.

Clinical Characteristics and Manifestation of Herpes Esophagitis: One Single-center Experience in Taiwan

We aimed to investigate the clinical characteristics of patients with herpes esophagitis (HE) based on endoscopic typing.Herpes simplex virus infection in the gastrointestinal tract primarily affects the esophagus. However, little is known about the presentation, endoscopic findings, and outcomes of HE.From 2003 to 2013, 47 patients with HE were identified histologically from among 1843 patients with esophageal ulcers. Personal data, underlying disease, esophagogastroduodenoscopy indication, endoscopic characteristics, pathological findings, laboratory data, and outcomes were collected. Endoscopic findings were classified into 3 types based on gross appearance and were correlated with clinical presentation.The mean age of patients was 62.04 ± 14.76 years, and most patients were men (39/47, 83%). The most common symptoms were odynophagia/dysphagia (20/47, 42.6%). Whereas 25 patients (53.2%) were diagnosed with malignancy, it was related to human immunodeficiency virus in only 1 patient (2.1%). HE was classified into 3 types based on endoscopic images: type I (n = 19), type II (n = 10), and type III (n = 18). The majority of patients with HE type III had sepsis (72%) and obvious leukocytosis than the other 2 types (P = 0.03). The overall mortality rate was 6.4% (3/47), and most of the patients who died (66.7% [2/3]) belonged to the endoscopic classification type III group. Clinical parameters were analyzed for the risk of poor outcome. Postchemotherapy and/or radiotherapy were associated with 30-day mortality after appearance of HE (P < 0.05).Herpes esophagitis primarily affects men and patients with malignancy or sepsis. However, the disease is usually self-limiting, and HE-related mortality is low. Relationship between severity of endoscopic findings and patients' outcome remains questionable. Further prospective study is needed.

A novel role for RGMa in modulation of bone marrow-derived dendritic cells maturation induced by lipopolysaccharide

Repulsive guidance molecule a (RGMa) is known to mediate immune responses and has been indicated to modulates T cell activation and autoimmune diseases by dendritic cells (DCs), which hints its significant function in the latter cells. The aim of our study, therefore, was to evaluate the function of RGMa in DC maturation. We found that small interfering RNA (siRNA) successfully silenced the expression of RGMa in DCs. Even after LPS stimulation, RGMa-silenced DCs displayed an immature morphology, characterized by small, round cells with a few cell processes and organelles, and many pinocytotic vesicles. In the presence of LPS, RGMa siRNA transfection markedly reduced levels of CD80, CD86, CD40, and MHC II expression, as well as the secretion of IL-12p70 and TNF-α. With LPS treatment, RGMa siRNA-transfected DCs also showed increased levels of IL-10 and endocytosis. Moreover, in the presence of LPS, RGMa siRNA-transfected DCs displayed a low ability to induce T cell proliferation and differentiation, compared with negative control (NTi)-transfected or control DCs (p<0.05 for both). We conclude that after LPS stimulation, RGMa siRNA-transfected DCs show immunoregulatory and tolerogenic characteristics, which provides new insights into the immune system.

Upregulated Expression of A20 on Monocytes is Associated With Increased Severity of Acute-on-Chronic Hepatitis B Liver Failure: A Case-Control Study

A20 expression is increased in various inflammatory diseases. However, the role of A20 in acute-on-chronic liver failure is unknown. This study was to evaluate A20 expression on monocytes and its associations with the severity of acute-on-chronic hepatitis B liver failure (ACHBLF). Thirty-seven patients with ACHBLF, 20 patients with chronic hepatitis B (CHB), and 15 healthy controls (HC) were enrolled in this case-control study. A20-positive monocytes were identified using flow cytometry. Serum levels of interleukin (IL)-10, IL-12p70, and TNF-α were determined using bead cytometry. A20 and IL-10 expressions were examined in THP-1 cells stimulated by lipopolysaccharide (LPS). The frequency of A20+ monocytes was significantly increased in patients with ACHBLF compared with HC (median [interquartile range, IQR]: 15.7 [22.8]% vs 2.5 [4.7]%, P < 0.001). Increased monocyte A20 expression was detected during the progression phase (including the mild/moderate and severe grades of ACHBLF) compared with patients in the recovery phase (both P < 0.05), and in the ACHBLF worsening group compared with patients in the improvement group (P < 0.001). LPS treatment upregulated A20 and IL-10 expressions in THP-1 cells. A20 expression on monocytes from patients with ACHBLF was positively correlated with total bilirubin (r = 0.60, P = 0.0001), direct bilirubin (r = 0.63, P < 0.0001), and MELD score (r = 0.43, P = 0.008), and inversely with prothrombin activity (r = -0.33, P = 0.046). IL-10 and TLR4 expression levels in monocytes, and serum levels of IL-10, IL-12p70, and TNF-α were increased in patients with ACHBLF compared with patients with CHB and HC. Increased A20 expression on monocytes was associated with the severity of ACHBLF.