The dynamic monitoring of immune status is crucial to the precise and individualized treatment of sepsis. In this study, we aim to introduce a model to describe and monitor the immune status of sepsis and to explore its prognostic value.A prospective observational study was carried out in Zhongshan Hospital, Fudan University, enrolling septic patients admitted between July 2016 and December 2018. Blood samples were collected at days 1 and 3. Serum cytokine levels (e.g., tumor necrosis factor-α [TNF-α], interleukin-10 [IL-10]) and CD14 monocyte human leukocyte antigen-D-related (HLA-DR) expression were measured to serve as immune markers. Classification of each immune status, namely systemic inflammatory response syndrome (SIRS), compensatory anti-inflammatory response syndrome (CARS), and mixed antagonistic response syndrome (MARS), was defined based on levels of immune markers. Changes of immune status were classified into four groups which were stabilization (SB), deterioration (DT), remission (RM), and non-remission (NR).A total of 174 septic patients were enrolled including 50 non-survivors. Multivariate analysis discovered that IL-10 and HLA-DR expression levels at day 3 were independent prognostic factors. Patients with MARS had the highest mortality rate. Immune status of 46.1% patients changed from day 1 to day 3. Among four groups of immune status changes, DT had the highest mortality rate, followed by NR, RM, and SB with mortality rates of 64.7%, 42.9%, and 11.2%, respectively.Severe immune disorder defined as MARS or deterioration of immune status defined as DT lead to the worst outcomes. The preliminary model of the classification and dynamic monitoring of immune status based on immune markers has prognostic values and is worthy of further investigation.Copyright: © World Journal of Emergency Medicine.

Definitions of sepsis and septic shock were last revised in 2001. Considerable advances have since been made into the pathobiology (changes in organ function, morphology, cell biology, biochemistry, immunology, and circulation), management, and epidemiology of sepsis, suggesting the need for reexamination.To evaluate and, as needed, update definitions for sepsis and septic shock.A task force (n = 19) with expertise in sepsis pathobiology, clinical trials, and epidemiology was convened by the Society of Critical Care Medicine and the European Society of Intensive Care Medicine. Definitions and clinical criteria were generated through meetings, Delphi processes, analysis of electronic health record databases, and voting, followed by circulation to international professional societies, requesting peer review and endorsement (by 31 societies listed in the Acknowledgment).Limitations of previous definitions included an excessive focus on inflammation, the misleading model that sepsis follows a continuum through severe sepsis to shock, and inadequate specificity and sensitivity of the systemic inflammatory response syndrome (SIRS) criteria. Multiple definitions and terminologies are currently in use for sepsis, septic shock, and organ dysfunction, leading to discrepancies in reported incidence and observed mortality. The task force concluded the term severe sepsis was redundant.Sepsis should be defined as life-threatening organ dysfunction caused by a dysregulated host response to infection. For clinical operationalization, organ dysfunction can be represented by an increase in the Sequential [Sepsis-related] Organ Failure Assessment (SOFA) score of 2 points or more, which is associated with an in-hospital mortality greater than 10%. Septic shock should be defined as a subset of sepsis in which particularly profound circulatory, cellular, and metabolic abnormalities are associated with a greater risk of mortality than with sepsis alone. Patients with septic shock can be clinically identified by a vasopressor requirement to maintain a mean arterial pressure of 65 mm Hg or greater and serum lactate level greater than 2 mmol/L (>18 mg/dL) in the absence of hypovolemia. This combination is associated with hospital mortality rates greater than 40%. In out-of-hospital, emergency department, or general hospital ward settings, adult patients with suspected infection can be rapidly identified as being more likely to have poor outcomes typical of sepsis if they have at least 2 of the following clinical criteria that together constitute a new bedside clinical score termed quickSOFA (qSOFA): respiratory rate of 22/min or greater, altered mentation, or systolic blood pressure of 100 mm Hg or less.These updated definitions and clinical criteria should replace previous definitions, offer greater consistency for epidemiologic studies and clinical trials, and facilitate earlier recognition and more timely management of patients with sepsis or at risk of developing sepsis.

Sepsis - which is a severe life-threatening infection with organ dysfunction - initiates a complex interplay of host pro-inflammatory and anti-inflammatory processes. Sepsis can be considered a race to the death between the pathogens and the host immune system, and it is the proper balance between the often competing pro- and anti-inflammatory pathways that determines the fate of the individual. Although the field of sepsis research has witnessed the failure of many highly touted clinical trials, a better understanding of the pathophysiological basis of the disorder and the mechanisms responsible for the associated pro- and anti-inflammatory responses provides a novel approach for treating this highly lethal condition. Biomarker-guided immunotherapy that is administered to patients at the proper immune phase of sepsis is potentially a major advance in the treatment of sepsis and in the field of infectious disease.

Sepsis is a heterogeneous syndrome comprising a highly diverse and dynamic mixture of hyperinflammatory and compensatory anti-inflammatory immune responses. This immune phenotypic diversity highlights the importance of proper patient selection for treatment with the immunomodulatory drugs that are entering clinical trials. To better understand the serial changes in immunity of critically ill patients and to evaluate the potential efficacy of blocking key inhibitory pathways in sepsis, we undertook a broad phenotypic and functional analysis of innate and acquired immunity in the same aliquot of blood from septic, critically ill nonseptic, and healthy donors. We also tested the ability of blocking the checkpoint inhibitors programmed death receptor-1 (PD-1) and its ligand (PD-L1) to restore the function of innate and acquired immune cells. Neutrophil and monocyte function (phagocytosis, CD163, cytokine expression) were progressively diminished as sepsis persisted. An increasing frequency in PD-L1+-suppressor phenotype neutrophils [low-density neutrophils (LDNs)] was also noted. PD-L1+ LDNs and defective neutrophil function correlated with disease severity, consistent with the potential importance of suppressive neutrophil populations in sepsis. Reduced neutrophil and monocyte function correlated both with their own PD-L1 expression and with PD-1 expression on CD8+ T cells and NK cells. Conversely, reduced CD8+ T cell and NK cell functions (IFN-γ production, granzyme B, and CD107a expression) correlated with elevated PD-L1+ LDNs. Importantly, addition of antibodies against PD-1 or PD-L1 restored function in neutrophil, monocyte, T cells, and NK cells, underlining the impact of the PD-1:PD-L1 axis in sepsis-immune suppression and the ability to treat multiple deficits with a single immunomodulatory agent.

Checkpoint regulators are a group of membrane-bound receptors or ligands expressed on immune cells to regulate the immune cell response to antigen presentation and other immune stimuli, such as cytokines, chemokines, and complement. In the context of profound immune activation, such as sepsis, the immune system can be rendered anergic by these receptors to prevent excessive inflammation and tissue damage. If this septic immunosuppression is prolonged, the host is unable to mount the appropriate immune response to a secondary insult or infection. This article describes the manner in which major regulators in the B7-CD28 family and their ligands mediate immunosuppression in sepsis.Copyright © 2019 Elsevier Inc. All rights reserved.

To investigate effects of Maxingloushi decoction on lung inflammation and programmed death markers (programmed death-1 [PD-1], programmed death-ligand 1 [PD-L1]) in the lung tissue, peripheral blood, and bronchoalveolar lavage fluid (BLF) in a mouse model of chronic obstructive pulmonary disease (COPD).Thirty-six mature male BALB/C mice were randomly divided into normal group (group A, =6), COPD model group (group B, =10), Maxingloushi decoction + COPD group (group C, =10), and PD-1 inhibitor + COPD group (group D, =10). The COPD model was established by smoke inhalation combined with lipopolysaccharide (LPS). Levels of PD-1 and PD-L1 in plasma and BLF were measured by enzyme-linked immunosorbent assay (ELISA). Histopathological techniques were used to semi-quantitatively analyze the immuno-fluorescence optical density (IOD) value of the lung tissue.In plasma and BLF, the expression of PD-1 in the group B was higher than that in the group A, and the expression of PD-L1 was lower than that in the group A. The expression of PD-1 and PD-L1 in the lung tissue was normalized in the group C in comparison with the group B (<0.05) and the group D (<0.05), and inflammatory cell infiltration in the lung tissue was also improved.These findings reveal that COPD causes an immune imbalance in the peripheral blood and lung tissue, and that both Maxingloushi decoction and PD-1 inhibitor treatment can mitigate lung inflammation in COPD by reducing PD-1 expression and increasing PD-L1 expression. The treatment effect of Maxingloushi decoction may be superior to that of PD-1 inhibitor.Copyright: © World Journal of Emergency Medicine.

Severe sepsis is typically characterized by initial cytokine-mediated hyperinflammation. Whether this hyperinflammatory phase is followed by immunosuppression is controversial. Animal studies suggest that multiple immune defects occur in sepsis, but data from humans remain conflicting.To determine the association of sepsis with changes in host innate and adaptive immunity and to examine potential mechanisms for putative immunosuppression.Rapid postmortem spleen and lung tissue harvest was performed at the bedsides of 40 patients who died in intensive care units (ICUs) of academic medical centers with active severe sepsis to characterize their immune status at the time of death (2009-2011). Control spleens (n = 29) were obtained from patients who were declared brain-dead or had emergent splenectomy due to trauma; control lungs (n = 20) were obtained from transplant donors or from lung cancer resections.Cytokine secretion assays and immunophenotyping of cell surface receptor-ligand expression profiles were performed to identify potential mechanisms of immune dysfunction. Immunohistochemical staining was performed to evaluate the loss of immune effector cells.The mean ages of patients with sepsis and controls were 71.7 (SD, 15.9) and 52.7 (SD, 15.0) years, respectively. The median number of ICU days for patients with sepsis was 8 (range, 1-195 days), while control patients were in ICUs for 4 or fewer days. The median duration of sepsis was 4 days (range, 1-40 days). Compared with controls, anti-CD3/anti-CD28-stimulated splenocytes from sepsis patients had significant reductions in cytokine secretion at 5 hours: tumor necrosis factor, 5361 (95% CI, 3327-7485) pg/mL vs 418 (95% CI, 98-738) pg/mL; interferon γ, 1374 (95% CI, 550-2197) pg/mL vs 37.5 (95% CI, -5 to 80) pg/mL; interleukin 6, 3691 (95% CI, 2313-5070) vs 365 (95% CI, 87-642) pg/mL; and interleukin 10, 633 (95% CI, -269 to 1534) vs 58 (95% CI, -39 to 156) pg/mL; (P <.001 for all). There were similar reductions in 5-hour lipopolysaccharide-stimulated cytokine secretion. Cytokine secretion in sepsis patients was generally less than 10% that in controls, independent of age, duration of sepsis, corticosteroid use, and nutritional status. Although differences existed between spleen and lung, flow cytometric analysis showed increased expression of selected inhibitory receptors and ligands and expansion of suppressor cell populations in both organs. Unique differences in cellular inhibitory molecule expression existed in immune cells isolated from lungs of sepsis patients vs cancer patients and vs transplant donors. Immunohistochemical staining showed extensive depletion of splenic CD4, CD8, and HLA-DR cells and expression of ligands for inhibitory receptors on lung epithelial cells.Patients who die in the ICU following sepsis compared with patients who die of nonsepsis etiologies have biochemical, flow cytometric, and immunohistochemical findings consistent with immunosuppression. Targeted immune-enhancing therapy may be a valid approach in selected patients with sepsis.

Reliable biomarkers for predicting subsequent sepsis among patients with suspected acute infection are lacking. In patients presenting to emergency departments (EDs) with suspected acute infection, we aimed to evaluate the reliability and discriminant ability of 47 leukocyte biomarkers as predictors of sepsis (Sequential Organ Failure Assessment score ≥ 2 at 24 h and/or 72 h following ED presentation).In a multi-centre cohort study in four EDs and intensive care units (ICUs), we standardised flow-cytometric leukocyte biomarker measurement and compared patients with suspected acute infection (cohort-1) with two comparator cohorts: ICU patients with established sepsis (cohort-2), and ED patients without infection or systemic inflammation but requiring hospitalization (cohort-3).Between January 2014 and February 2016, we recruited 272, 59 and 75 patients to cohorts 1, 2, and 3, respectively. Of 47 leukocyte biomarkers, 14 were non-reliable, and 17 did not discriminate between the three cohorts. Discriminant analyses for predicting sepsis within cohort-1 were undertaken for eight neutrophil (cluster of differentiation antigens (CD) CD15; CD24; CD35; CD64; CD312; CD11b; CD274; CD279), seven monocyte (CD35; CD64; CD312; CD11b; HLA-DR; CD274; CD279) and a CD8 T-lymphocyte biomarker (CD279). Individually, only higher neutrophil CD279 [OR 1.78 (95% CI 1.23-2.57); P = 0.002], higher monocyte CD279 [1.32 (1.03-1.70); P = 0.03], and lower monocyte HLA-DR [0.73 (0.55-0.97); P = 0.03] expression were associated with subsequent sepsis. With logistic regression the optimum biomarker combination was increased neutrophil CD24 and neutrophil CD279, and reduced monocyte HLA-DR expression, but no combination had clinically relevant predictive validity.From a large panel of leukocyte biomarkers, immunosuppression biomarkers were associated with subsequent sepsis in ED patients with suspected acute infection.NCT02188992.

To provide an update to "Surviving Sepsis Campaign Guidelines for Management of Sepsis and Septic Shock: 2012".A consensus committee of 55 international experts representing 25 international organizations was convened. Nominal groups were assembled at key international meetings (for those committee members attending the conference). A formal conflict-of-interest (COI) policy was developed at the onset of the process and enforced throughout. A stand-alone meeting was held for all panel members in December 2015. Teleconferences and electronic-based discussion among subgroups and among the entire committee served as an integral part of the development.The panel consisted of five sections: hemodynamics, infection, adjunctive therapies, metabolic, and ventilation. Population, intervention, comparison, and outcomes (PICO) questions were reviewed and updated as needed, and evidence profiles were generated. Each subgroup generated a list of questions, searched for best available evidence, and then followed the principles of the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system to assess the quality of evidence from high to very low, and to formulate recommendations as strong or weak, or best practice statement when applicable.The Surviving Sepsis Guideline panel provided 93 statements on early management and resuscitation of patients with sepsis or septic shock. Overall, 32 were strong recommendations, 39 were weak recommendations, and 18 were best-practice statements. No recommendation was provided for four questions.Substantial agreement exists among a large cohort of international experts regarding many strong recommendations for the best care of patients with sepsis. Although a significant number of aspects of care have relatively weak support, evidence-based recommendations regarding the acute management of sepsis and septic shock are the foundation of improved outcomes for these critically ill patients with high mortality.

The objective of this study was to refine the APACHE (Acute Physiology, Age, Chronic Health Evaluation) methodology in order to more accurately predict hospital mortality risk for critically ill hospitalized adults. We prospectively collected data on 17,440 unselected adult medical/surgical intensive care unit (ICU) admissions at 40 US hospitals (14 volunteer tertiary-care institutions and 26 hospitals randomly chosen to represent intensive care services nationwide). We analyzed the relationship between the patient's likelihood of surviving to hospital discharge and the following predictive variables: major medical and surgical disease categories, acute physiologic abnormalities, age, preexisting functional limitations, major comorbidities, and treatment location immediately prior to ICU admission. The APACHE III prognostic system consists of two options: (1) an APACHE III score, which can provide initial risk stratification for severely ill hospitalized patients within independently defined patient groups; and (2) an APACHE III predictive equation, which uses APACHE III score and reference data on major disease categories and treatment location immediately prior to ICU admission to provide risk estimates for hospital mortality for individual ICU patients. A five-point increase in APACHE III score (range, 0 to 299) is independently associated with a statistically significant increase in the relative risk of hospital death (odds ratio, 1.10 to 1.78) within each of 78 major medical and surgical disease categories. The overall predictive accuracy of the first-day APACHE III equation was such that, within 24 h of ICU admission, 95 percent of ICU admissions could be given a risk estimate for hospital death that was within 3 percent of that actually observed (r2 = 0.41; receiver operating characteristic = 0.90). Recording changes in the APACHE III score on each subsequent day of ICU therapy provided daily updates in these risk estimates. When applied across the individual ICUs, the first-day APACHE III equation accounted for the majority of variation in observed death rates (r2 = 0.90, p less than 0.0001).

PD-1 is an immunoinhibitory receptor expressed by activated T cells, B cells, and myeloid cells. Mice deficient in PD-1 exhibit a breakdown of peripheral tolerance and demonstrate multiple autoimmune features. We report here that the ligand of PD-1 (PD-L1) is a member of the B7 gene family. Engagement of PD-1 by PD-L1 leads to the inhibition of T cell receptor-mediated lymphocyte proliferation and cytokine secretion. In addition, PD-1 signaling can inhibit at least suboptimal levels of CD28-mediated costimulation. PD-L1 is expressed by antigen-presenting cells, including human peripheral blood monocytes stimulated with interferon gamma, and activated human and murine dendritic cells. In addition, PD-L1 is expressed in nonlymphoid tissues such as heart and lung. The relative levels of inhibitory PD-L1 and costimulatory B7-1/B7-2 signals on antigen-presenting cells may determine the extent of T cell activation and consequently the threshold between tolerance and autoimmunity. PD-L1 expression on nonlymphoid tissues and its potential interaction with PD-1 may subsequently determine the extent of immune responses at sites of inflammation.

Sepsis, among other pathologies, is an endotoxin tolerance (ET)-related disease. On admission, we classified 48 patients with sepsis into 3 subgroups according to the ex vivo response to lipopolysaccharide. This response correlates with the Acute Physiology and Chronic Health Evaluation (APACHE) II score and the ET degree. Moreover, the ET-related classification determines the outcome of these patients. Programmed cell death-ligand 1 (PD-L1) expression on septic monocytes is also linked with ET status. In addition to the regulation of cytokine production, one of the hallmarks of ET that significantly affects patients with sepsis is T-cell proliferation impairment or a poor switch to the adaptive response. PD-L1/programmed cell death-1 (PD-1) blocking and knockdown assays on tolerant monocytes from both patients with sepsis and the in vitro model reverted the impaired adaptive response. Mechanistically, the transcription factor hypoxia-inducible factor-1α (HIF1α) has been translocated into the nucleus and drives PD-L1 expression during ET in human monocytes. This fact, together with patient classification according to the ex vivo lipopolysaccharide response, opens an interesting field of study and potential personalized clinical applications, not only for sepsis but also for all ET-associated pathologies.© The Author(s) 2017. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.

\n Sepsis, a leading cause of death worldwide, involves concomitant expression of an overzealous inflammatory response and inefficient bacterial clearance. Macrophage function is pivotal to the development of these two aspects during sepsis; however, the mechanisms underlying these changes remain unclear. Here we report that the PD-1:PD-L pathway appears to be a determining factor of the outcome of sepsis, regulating the delicate balance between effectiveness and damage by the antimicrobial immune response. To this end we observed that PD-1\n −/−\n mice were markedly protected from the lethality of sepsis, accompanied by a decreased bacterial burden and suppressed inflammatory cytokine response. To the extent that this is a macrophage-specific aspect of the effects of PD-1, we found the following: first, peritoneal macrophages expressed significantly higher levels of PD-1 during sepsis, which was associated with their development of cellular dysfunction; second, when peritoneal macrophages were depleted (using clodronate liposomes) from PD-1\n −/−\n mice, the animals' bactericidal capacity was lowered, their inflammatory cytokine levels were elevated, and protection from septic lethality was diminished; and third, blood monocytes from both septic mice and patients with septic shock shared markedly increased PD-1 levels. Together, these data suggest that PD-1 may not only be a dysfunctional marker/effector of macrophages/monocytes, but may also be a potential therapeutic target for designing measures to modulate the innate immune response, thereby preventing the detrimental effects of sepsis.\n

This study aimed to investigate the possible relationship between the two biomarkers presepsin and procalcitonin (PCT) and monocyte immune function, and to explore their combination in mortality prediction in the early stage of sepsis. A total of 198 patients with bacterial infection and diagnosed with sepsis and 40 healthy control subjects were included. Blood samples were collected on admission within 24 h. Plasma concentrations of presepsin and PCT were measured. Expression of monocyte surface CD14, programmed cell death receptor ligand-1 (PD-L1) and human leucocyte Ag (HLA)-DR were determined using flow cytometry. Levels of plasma presepsin and PCT were significantly higher under septic conditions, and increased with the progression of sepsis. Monocyte CD14 and HLA-DR expression were decreased, while PD-L1 was overexpressed in sepsis compared to control. Presepsin and PCT concentrations were positively correlated with Sequential Organ Failure Assessment score, Acute Physiology and Chronic Health Evaluation System II score and PD-L1, while they were negatively correlated with CD14 and HLA-DR. Presepsin plus monocyte HLA-DR mean fluorescence intensity had the highest prognostic value over other parameters alone or in combination. Presepsin and PCT had a weak correlation with monocyte dysfunction during early sepsis. The combination of presepsin and monocyte HLA-DR could help improve prognostic value.

Natural killer (NK) cells play a major role in immune tolerance after sepsis, and the programmed cell death 1 (PD-1) and programmed cell death ligand 1 (PD-L1) system mediates evasion of host immunity. The correlation between PD-L1 levels in NK cells and the prognosis of patients with sepsis, however, has not been elucidated. Thus, it was hypothesized that PD-L1 in NK cells could be a novel biomarker of the mortality for sepsis patients.

Programmed death 1 (PD-1), an inhibitory receptor expressed on activated lymphocytes, regulates tolerance and autoimmunity. PD-1 has two ligands: PD-1 ligand 1 (PD-L1), which is expressed broadly on hematopoietic and parenchymal cells, including pancreatic islet cells; and PD-L2, which is restricted to macrophages and dendritic cells. To investigate whether PD-L1 and PD-L2 have synergistic or unique roles in regulating T cell activation and tolerance, we generated mice lacking PD-L1 and PD-L2 (PD-L1/PD-L2(-/-) mice) and compared them to mice lacking either PD-L. PD-L1 and PD-L2 have overlapping functions in inhibiting interleukin-2 and interferon-gamma production during T cell activation. However, PD-L1 has a unique and critical role in controlling self-reactive T cells in the pancreas. Our studies with bone marrow chimeras demonstrate that PD-L1/PD-L2 expression only on antigen-presenting cells is insufficient to prevent the early onset diabetes that develops in PD-L1/PD-L2(-/-) non-obese diabetic mice. PD-L1 expression in islets protects against immunopathology after transplantation of syngeneic islets into diabetic recipients. PD-L1 inhibits pathogenic self-reactive CD4+ T cell-mediated tissue destruction and effector cytokine production. These data provide evidence that PD-L1 expression on parenchymal cells rather than hematopoietic cells protects against autoimmune diabetes and point to a novel role for PD-1-PD-L1 interactions in mediating tissue tolerance.

Both positive and negative regulatory roles have been suggested for the B7 family member PD-L1(B7-H1). PD-L1 is expressed on antigen-presenting cells (APCs), activated T cells, and a variety of tissues, but the functional significance of PD-L1 on each cell type is not yet clear. To dissect the functions of PD-L1 in vivo, we generated PD-L1-deficient (PD-L1(-/-)) mice. CD4(+) and CD8(+) T cell responses were markedly enhanced in PD-L1(-/-) mice compared with wild-type mice in vitro and in vivo. PD-L1(-/-) dendritic cells stimulated greater wild-type CD4(+) T cell responses than wild-type dendritic cells, and PD-L1(-/-) CD4(+) T cells produced more cytokines than wild-type CD4(+) T cells in vitro, demonstrating an inhibitory role for PD-L1 on APCs and T cells. In vivo CD8(+) T cell responses also were significantly enhanced, indicating that PD-L1 has a role in limiting the expansion or survival of CD8(+) T cells. Studies using the myelin oligodendrocyte model of experimental autoimmune encephalomyelitis showed that PD-L1 on T cells and in host tissues limits responses of self-reactive CD4(+) T cells in vivo. PD-L1 deficiency converted the 129S4/SvJae strain from a resistant to experimental autoimmune encephalomyelitis-susceptible strain. Transfer of encephalitogenic T cells from wild-type mice into PD-L1(-/-) recipients led to exacerbated disease. Disease was even more severe in PD-L1(-/-) recipients of PD-L1(-/-) T cells. These results demonstrate that PD-L1 on T cells, APCs, and host tissue inhibits naïve and effector T cell responses and plays a critical role in T cell tolerance.

Checkpoint inhibitors like anti-PD1/PD-L1 have demonstrated significant therapeutic efficacy in a subset of patients partly through reinvigoration of CD8 T cells. However, their impact on myeloid cells remains largely unknown. Here, we report that anti-PD-L1 treatment favorably impacts the phenotype and function of tumor macrophages by polarizing the macrophage compartment toward a more proinflammatory phenotype. This phenotype was characterized by a decrease in Arginase-I (ARG1) expression and an increase in iNOS, MHCII, and CD40 expression. Whole-transcriptome profiling further confirmed extensive polarization of both tumor monocytes and macrophages from a suppressive to a proinflammatory, immunostimulatory phenotype. This polarization was driven mainly through IFNγ and was associated with enhanced T-cell activity. Transfer of monocytes into anti-PD-L1-treated tumor-bearing mice led to macrophage differentiation into a more proinflammatory phenotype, with an increase in CD8 T cells expressing granzyme-B and an increase in the CD8/Treg ratio compared with control-treated mice. Although in responsive tumor models, anti-PD-L1 treatment remodeled the macrophage compartment with beneficial effects on T cells, both macrophage reprogramming and depletion were needed to maximize anti-PD-L1 responses in a tumor immune contexture with high macrophage burden. Our results demonstrate that anti-PD-L1 treatment can favorably remodel the macrophage compartment in responsive tumor models toward a more proinflammatory phenotype, mainly through increased IFNγ levels. They also suggest that directly targeting these cells with reprogramming and depleting agents may further augment the breadth and depth of response to anti-PD-L1 treatment in less responsive or more macrophage-dense tumor microenvironments. SIGNIFICANCE: This work demonstrates that increased IFNγ signaling following anti-PD-L1 treatment can remodel the macrophage compartment to enhance T-cell responses. http://cancerres.aacrjournals.org/content/canres/79/7/1493/F1.large.jpg.©2019 American Association for Cancer Research.

The immuno-inhibitory checkpoint PD-L1, regulated by tumor cells and antigen-presenting cells (APCs), dampened the activation of T cells from the PD-1/PD-L1 axis. PD-L1-expressing APCs rather than tumor cells demonstrated the essential anti-tumor effects of anti-PD-L1 monotherapy in preclinical tumor models. Using the murine tumor model, we investigated whether anti-PD-L1 antibody increased the antigen-specific immune response and anti-tumor effects induced by the antigen-specific protein vaccine, as well as the possible mechanisms regarding activation of APCs. Anti-PD-L1 antibody combined with the PEK protein vaccine generated more potent E7-specific immunity (including the number and cytotoxic activity of E7-specific cytotoxic CD8+ T lymphocytes) and anti-tumor effects than protein vaccine alone. Anti-PD-L1 antibody enhanced the maturation of dendritic cells and the proportion of M1-like macrophages in tumor-draining lymph nodes and tumors in tumor-bearing mice treated with combinatorial therapy. PD-L1 blockade overturned the immunosuppressive status of the tumor microenvironment and then enhanced the E7 tumor-specific antigen-specific immunity and anti-tumor effects generated by an E7-specific protein vaccine through modulation of APCs in an E7-expressing small tumor model. Tumor-specific antigen (like HPV E7 antigen)-specific immunotherapy combined with APC-targeting modality by PD-L1 blockade has a high translational potential in E7-specific cancer therapy.

The relationship between fluctuating cytokine concentrations in plasma and the outcome of sepsis is complex. We postulated that early measurement of the activation of nuclear factor kappaB (NF-kappaB), a transcriptional regulatory protein involved in proinflammatory cytokine expression, may help to predict the outcome of sepsis. We determined NF-kappaB activation in peripheral blood mononuclear cells of 34 patients with severe sepsis (23 survivors and 11 nonsurvivors) and serial concentrations of inflammatory cytokines (interleukin-6, interleukin-1, and tumor necrosis factor) and various endogenous antagonists in plasma. NF-kappaB activity was significantly higher in nonsurvivors and correlated strongly with the severity of illness (APACHE II score), although neither was related to the cytokine levels. Apart from NF-kappaB activity, the interleukin-1 receptor antagonist was the only cytokine tested whose level in plasma was of value in predicting mortality by logistic regression analysis. These results underscore the prognostic value of early measurement of NF-kappaB activity in patients with severe sepsis.

Binding activity for nuclear factor kappa B (NFkappaB) consensus probes was studied in nuclear extracts from peripheral blood mononuclear cells of 15 septic patients (10 surviving and 5 not surviving). Nonsurvivors could be distinguished from survivors by an increase in NFkappaB binding activity during the observation period (P < 0.001). The increase in NFkappaB binding activity was comparable to the APACHE-II score as a predictor of outcome. Intravenous somatic gene transfer with an expression plasmid coding for IkappaBalpha was used to investigate the role of members of the NFkappaB family in a mouse model of endotoxemia. In this model, increased NFkappaB binding activity was present after injection of LPS. Intravenous somatic gene transfer with IkappaBalpha given before LPS attenuated renal NFkappaB binding activity and increased survival. Endothelial cells and monocytes/macrophages were the major target cells for somatic gene transfer, transfected with an average transfection efficiency of 20-35%. Tissue factor, a gene under regulatory control of NFkappaB, was induced by LPS. Somatic gene transfer with a reporter plasmid containing the functional tissue factor promoter demonstrated NFkappaB-dependent stimulation by LPS. Intravenous somatic gene transfer with IkappaBalpha reduced LPS-induced renal tissue factor expression, activation of the plasmatic coagulation system (decrease of thrombin-antithrombin III complexes) and renal fibrin/fibrinogen deposition. Somatic gene transfer with an expression plasmid with tissue factor cDNA in the antisense direction (in contrast to sense or vector alone) also increased survival. Furthermore, antisense tissue factor decreased renal tissue factor expression and the activation of the plasmatic coagulation system.

Immunotherapeutic approaches, particularly programmed death 1/programmed death ligand 1 (PD-1/PD-L1) blockade, have improved the treatment of non-small-cell lung cancer (NSCLC), supporting the premise that evasion of immune destruction is of importance for NSCLC progression. However, the signals responsible for upregulation of PD-L1 in NSCLC cells and whether they are integrated with the regulation of other immune-related genes are not known. Mucin 1 (MUC1) is aberrantly overexpressed in NSCLC, activates the nuclear factor-κB (NF-κB) p65→︀ZEB1 pathway and confers a poor prognosis. The present studies demonstrate that MUC1-C activates PD-L1 expression in NSCLC cells. We show that MUC1-C increases NF-κB p65 occupancy on the CD274/PD-L1 promoter and thereby drives CD274 transcription. Moreover, we demonstrate that MUC1-C-induced activation of NF-κB→︀ZEB1 signaling represses the TLR9 (toll-like receptor 9), IFNG, MCP-1 (monocyte chemoattractant protein-1) and GM-CSF genes, and that this signature is associated with decreases in overall survival. In concert with these results, targeting MUC1-C in NSCLC tumors suppresses PD-L1 and induces these effectors of innate and adaptive immunity. These findings support a previously unrecognized central role for MUC1-C in integrating PD-L1 activation with suppression of immune effectors and poor clinical outcome.

Emerging evidence has highlighted the host immune system in modulating the patient response to chemotherapy, but the mechanism of this modulation remains unclear. The aim of this study was to analyze the effect of chemotherapy on antitumor immunity in the tumor microenvironment of ovarian cancer. Treatment of ovarian cancer cell lines with various chemotherapeutic agents resulted in upregulated expression of MHC class I and programmed cell death 1 ligand 1 (PD-L1) in a NF-κB-dependent manner and suppression of antigen-specific T-cell function in vitro. In a mouse model of ovarian cancer, treatment with paclitaxel increased CD8(+) T-cell infiltration into the tumor site, upregulated PD-L1 expression, and activated NF-κB signaling. In particular, tumor-bearing mice treated with a combination of paclitaxel and a PD-L1/PD-1 signal blockade survived longer than mice treated with paclitaxel alone. In summary, we found that chemotherapy induces local immune suppression in ovarian cancer through NF-κB-mediated PD-L1 upregulation. Thus, a combination of chemotherapy and immunotherapy targeting the PD-L1/PD-1 signaling axis may improve the antitumor response and offers a promising new treatment modality against ovarian cancer.©2015 American Association for Cancer Research.