Contribution of Dendritic Cell Responses to Sepsis-Induced Immunosuppression and to Susceptibility to Secondary Pneumonia

Dendritic cells (DCs) are bone marrow derived cells which continuously seed in peripheral tissue. During infection, DCs play an essential interface between innate and adaptive immunity. Pneumonia is a lung inflammation triggered by pathogens and is characterized by excessive release of inflammatory cytokines that activate innate and acquired immunity. Pneumonia induces a rapid and protracted state of susceptibility to secondary infection, a state so-called sepsis-induced immunosuppression. In this review, we focus on the role of DCs in the development of this state of immunosuppression. Early during inflammation, activated DCs are characterized by decreased capacity of antigen (cross)- presentation of newly encountered antigens and decreased production of immunogenic cytokines, and sepsis-induced immunosuppression is mainly explained by a depletion of immature DCs which had all become mature. At a later stage, newly formed respiratory immature DCs are locally programmed by an immunological scare left-over by inflammation to induce tolerance. Tolerogenic Blimp1+ DCs produce suppressive cytokines such as tumor growth factor-B and participate to the maintenance of a local tolerogenic environment notably characterized by accumulation of Treg cells. In mice, the restoration of the immunogenic functions of DCs restores the mucosal immune response to pathogens. In humans, the modulation of inflammation by glucocorticoid during sepsis or trauma preserves DC immunogenic functions and is associated with resistance to secondary pneumonia. Finally, we propose that the alterations of DCs during and after inflammation can be used as biomarkers of susceptibility to secondary pneumonia and are promising therapeutic targets to enhance outcomes of patients with secondary pneumonia

Efficacy and safety of early target-controlled plasma volume replacement with a balanced gelatine solution versus a balanced electrolyte solution in patients with severe sepsis/septic shock: study protocol, design, and rationale of a prospective, randomized, controlled, double-blind, multicentric, international clinical trial

Col·loides; Gelatina; SèpsiaColoides; Gelatina; SepticemiaColloids; Gelatine; SepsisBackground Sepsis is associated with capillary leakage and vasodilatation and leads to hypotension and tissue hypoperfusion. Early plasma volume replacement is required to achieve haemodynamic stability (HDS) and maintain adequate tissue oxygenation. The right choice of fluids to be used for plasma volume replacement (colloid or crystalloid solutions) is still a matter of debate, and large trials investigating the use of colloid solutions containing gelatine are missing. This study aims to investigate the efficacy and safety of plasma volume replacement using either a combined gelatine-crystalloid regime (1:1 ratio) or a pure crystalloid regime. Methods This is a prospective, controlled, randomized, double-blind, international, multicentric phase IV study with two parallel groups that is planned to be conducted at European intensive care units (ICUs) in a population of patients with hypovolaemia in severe sepsis/septic shock. A total of 608 eligible patients will be randomly assigned to receive either a gelatine-crystalloid regime (Gelaspan® 4% and Sterofundin® ISO, B. Braun Melsungen AG, in a 1:1 ratio) or a pure crystalloid regime (Sterofundin® ISO) for plasma volume replacement. The primary outcome is defined as the time needed to achieve HDS. Plasma volume replacement will be target-controlled, i.e. fluids will only be administered to volume-responsive patients. Volume responsiveness will be assessed through passive leg raising or fluid challenges. The safety and efficacy of both regimens will be assessed daily for 28 days or until ICU discharge (whichever occurs first) as the secondary outcomes of this study. Follow-up visits/calls will be scheduled on day 28 and day 90. Discussion This study aims to generate evidence regarding which regimen—a gelatine-crystalloid regimen or a pure crystalloid regimen—is more effective in achieving HDS in critically ill patients with hypovolaemia. Study participants in both groups will benefit from the increased safety of target-controlled plasma volume replacement, which prevents fluid administration to already haemodynamically stable patients and reduces the risk of harmful fluid overload.In this clinical study, B. Braun Melsungen AG, Carl-Braun Str. 1, D-34212 Melsungen acts as the sponsor, funder and data holder of this study. Additionally, it is the manufacturer of IMP, as well as the co-author and medical writer of this manuscript. B. Braun Melsungen AG organized protocol development and contracted a contract research organization (CRO) for clinical trial application, monitoring, and collection/analysis of study data. Investigational tests and reference products will be produced and delivered by B. Braun Melsungen AG to all participating sites. Open Access funding enabled and organized by Projekt DEAL

Increased creatinine clearance in polytrauma patients with normal serum creatinine: a retrospective observational study

International audienceINTRODUCTION: The aim of this study, performed in an intensive care unit (ICU) population with a normal serum creatinine, was to estimate urinary creatinine clearance (CLCR) in a population of polytrauma patients (PT) through a comparison with a population of non trauma patients (NPT). METHODS: This was a retrospective, observational study in a medical and surgical ICU in a university hospital. A total of 284 patients were consecutively included. Two different groups were studied: PT (n = 144) and NPT (n = 140). Within the second week after admission to the ICU, renal function was assessed using serum creatinine, 24 h urinary CLCR . RESULTS: Among the 106 patients with a CLCR above 120 mL minute(-1) 1.73 m(-2), 79 were PT and 27 NPT (P < 0.0001). Only 63 patients had a CLCR below 60 mL minute(-1) 1.73 m(-2) with 15 PT and 48 NPT (P < 0.0001). Patients with CLCR greater than 120 mL minute(-1). 1.73 m(-2) were younger, had a lower SAPS II score and a higher male ratio as compared to those having CLCR lower than 120 mL minute(-1). 1.73 m(-2). Through a logistic regression analysis, age and trauma were the only factors independently correlated to CLCR. CONCLUSIONS: In ICU patients with normal serum creatinine, CLCR, is higher in PT than in NPT. The measure of CLCR should be proposed as routine for PT patients in order to adjust dose regimen, especially for drugs with renal elimination

Empiric antimicrobial therapy for ventilator-associated pneumonia after brain injury

International audienceIssues regarding recommendations on empiric antimicrobial therapy for ventilator-associated pneumonia (VAP) have emerged in specific populations.To develop and validate a score to guide empiric therapy in brain-injured patients with VAP, we prospectively followed a cohort of 379 brain-injured patients in five intensive care units. The score was externally validated in an independent cohort of 252 brain-injured patients and its extrapolation was tested in 221 burn patients.The multivariate analysis for predicting resistance (incidence 16.4%) showed two independent factors: preceding antimicrobial therapy ≥48 h (p\textless0.001) and VAP onset ≥10 days (p\textless0.001); the area under the receiver operating characteristic curve (AUC) was 0.822 (95% CI 0.770-0.883) in the learning cohort and 0.805 (95% CI 0.732-0.877) in the validation cohort. The score built from the factors selected in multivariate analysis predicted resistance with a sensitivity of 83%, a specificity of 71%, a positive predictive value of 37% and a negative predictive value of 96% in the validation cohort. The AUC of the multivariate analysis was poor in burn patients (0.671, 95% CI 0.596-0.751).Limited-spectrum empirical antimicrobial therapy has low risk of failure in brain-injured patients presenting with VAP before day 10 and when prior antimicrobial therapy lasts \textless48 

Ann Intensive Care

Despite a large body of evidence, the implementation of guidelines on hemodynamic optimization and goal-directed therapy remains limited in daily routine practice. To facilitate/accelerate this implementation, a panel of experts in the field proposes an approach based on six relevant questions/answers that are frequently mentioned by clinicians, using a critical appraisal of the literature and a modified Delphi process. The mean arterial pressure is a major determinant of organ perfusion, so that the authors unanimously recommend not to tolerate absolute values below 65 mmHg during surgery to reduce the risk of postoperative organ dysfunction. Despite well-identified limitations, the authors unanimously propose the use of dynamic indices to rationalize fluid therapy in a large number of patients undergoing non-cardiac surgery, pending the implementation of a "validity criteria checklist" before applying volume expansion. The authors recommend with a good agreement mini- or non-invasive stroke volume/cardiac output monitoring in moderate to high-risk surgical patients to optimize fluid therapy on an individual basis and avoid volume overload. The authors propose to use fluids and vasoconstrictors in combination to achieve optimal blood flow and maintain perfusion pressure above the thresholds considered at risk. Although purchase of disposable sensors and stand-alone monitors will result in additional costs, the authors unanimously acknowledge that there are data strongly suggesting this may be counterbalanced by a sustained reduction in postoperative morbidity and hospital lengths of stay. Beside existing guidelines, knowledge and explicit clinical reasoning tools followed by decision algorithms are mandatory to implement individualized hemodynamic optimization strategies and reduce postoperative morbidity and duration of hospital stay in high-risk surgical patients

CpG-ODN and MPLA Prevent Mortality in a Murine Model of Post-Hemorrhage-Staphyloccocus aureus Pneumonia

Infections are the most frequent cause of complications in trauma patients. Post-traumatic immune suppression (IS) exposes patients to pneumonia (PN). The main pathogen involved in PN is Methicillin Susceptible Staphylococcus aureus (MSSA). Dendritic cells () may be centrally involved in the IS. We assessed the consequences of hemorrhage on pneumonia outcomes and investigated its consequences on DCs functions. A murine model of hemorrhagic shock with a subsequent MSSA pneumonia was used. Hemorrhage decreased the survival rate of infected mice, increased systemic dissemination of sepsis and worsened inflammatory lung lesions. The mRNA expression of Tumor Necrosis Factor-alpha (TNF-α), Interferon-beta (IFN-β) and Interleukin (IL)-12p40 were mitigated for hemorrhaged-mice. The effects of hemorrhage on subsequent PN were apparent on the pDCs phenotype (reduced MHC class II, CD80, and CD86 molecule membrane expression). In addition, hemorrhage dramatically decreased CD8+ cDCs- and CD8- cDCs-induced allogeneic T-cell proliferation during PN compared with mice that did not undergo hemorrhage. In conclusion, hemorrhage increased morbidity and mortality associated with PN; induced severe phenotypic disturbances of the pDCs subset and functional alterations of the cDCs subset. After hemorrhage, a preventive treatment with CpG-ODN or Monophosphoryl Lipid A increased transcriptional activity in DCs (TNF-α, IFN-β and IL-12p40) and decreased mortality of post-hemorrhage MSSA pneumonia

Corticotherapy for traumatic brain-injured Patients - The Corti-TC trial: study protocol for a randomized controlled trial

<p>Abstract</p> <p>Background</p> <p>Traumatic brain injury (TBI) is a main cause of severe prolonged disability of young patients. Hospital acquired pneumonia (HAP) add to the morbidity and mortality of traumatic brain-injured patients. In one study, hydrocortisone for treatment of traumatic-induced corticosteroid insufficiency (CI) in multiple injured patients has prevented HAP, particularly in the sub-group of patients with severe TBI. Fludrocortisone is recommended in severe brain-injured patients suffering from acute subarachnoid hemorrhage. Whether an association of hydrocortisone with fludrocortisone protects from HAP and improves neurological recovery is uncertain. The aim of the current study is to compare corticotherapy to placebo for TBI patients with CI.</p> <p>Methods</p> <p>The CORTI-TC (Corticotherapy in traumatic brain-injured patients) trial is a multicenter, randomized, placebo controlled, double-blind, two-arms study. Three hundred and seventy six patients hospitalized in Intensive Care Unit with a severe traumatic brain injury (Glasgow Coma Scale ≤ 8) are randomized in the first 24 hours following trauma to hydrocortisone (200 mg.day^-1for 7 days, 100 mg on days 8-9 and 50 mg on day-10) with fludrocortisone (50 μg for 10 days) or double placebo. The treatment is stopped if patients have an appropriate adrenal response. The primary endpoint is HAP on day-28. The endpoint of the ancillary study is the neurological status on 6 and 12 months.</p> <p>Discussion</p> <p>The CORTI-TC trial is the first randomized controlled trial powered to investigate whether hydrocortisone with fludrocortisone in TBI patients with CI prevent HAP and improve long term recovery.</p> <p>Trial registration</p> <p><a href="http://www.clinicaltrials.gov/ct2/show/NCT01093261">NCT01093261</a></p

CD4CD8αα Lymphocytes, A Novel Human Regulatory T Cell Subset Induced by Colonic Bacteria and Deficient in Patients with Inflammatory Bowel Disease

It has become evident that bacteria in our gut affect health and disease, but less is known about how they do this. Recent studies in mice showed that gut Clostridium bacteria and their metabolites can activate regulatory T cells (Treg) that in turn mediate tolerance to signals that would ordinarily cause inflammation. In this study we identify a subset of human T lymphocytes, designated CD4CD8αα T cells that are present in the surface lining of the colon and in the blood. We demonstrate Treg activity and show these cells to be activated by microbiota; we identify F. prausnitzii, a core Clostridium strain of the human gut microbiota, as a major inducer of these Treg cells. Interestingly, there are fewer F. prausnitzii in individuals suffering from inflammatory bowel disease (IBD), and accordingly the CD4CD8αα T cells are decreased in the blood and gut of patients with IBD. We argue that CD4CD8αα colonic Treg probably help control or prevent IBD. These data open the road to new diagnostic and therapeutic strategies for the management of IBD and provide new tools to address the impact of the intestinal microbiota on the human immune system