Identification of a sub-group of critically ill patients with high risk of intensive care unit-acquired infections and poor clinical course using a transcriptomic score.

BACKGROUND: The development of stratification tools based on the assessment of circulating mRNA of genes involved in the immune response is constrained by the heterogeneity of septic patients. The aim of this study is to develop a transcriptomic score based on a pragmatic combination of immune-related genes detected with a prototype multiplex PCR tool. METHODS: As training cohort, we used the gene expression dataset obtained from 176 critically ill patients enrolled in the REALISM study (NCT02638779) with various etiologies and still hospitalized in intensive care unit (ICU) at day 5-7. Based on the performances of each gene taken independently to identify patients developing ICU-acquired infections (ICU-AI) after day 5-7, we built an unweighted score assuming the independence of each gene. We then determined the performances of this score to identify a subgroup of patients at high risk to develop ICU-AI, and both longer ICU length of stay and mortality of this high-risk group were assessed. Finally, we validated the effectiveness of this score in a retrospective cohort of 257 septic patients. RESULTS: This transcriptomic score (TScore) enabled the identification of a high-risk group of patients (49%) with an increased rate of ICU-AI when compared to the low-risk group (49% vs. 4%, respectively), with longer ICU length of stay (13 days [95% CI 8-30] vs. 7 days [95% CI 6-9], p < 0.001) and higher ICU mortality (15% vs. 2%). High-risk patients exhibited biological features of immune suppression with low monocytic HLA-DR levels, higher immature neutrophils rates and higher IL10 concentrations. Using the TScore, we identified 160 high-risk patients (62%) in the validation cohort, with 30% of ICU-AI (vs. 18% in the low-risk group, p = 0.06), and significantly higher mortality and longer ICU length of stay. CONCLUSIONS: The transcriptomic score provides a useful and reliable companion diagnostic tool to further develop immune modulating drugs in sepsis in the context of personalized medicine.

Identification of a transcriptome profile associated with improvement of organ function in septic shock patients after early supportive therapy.

BACKGROUND: Septic shock is the most severe complication of sepsis and this syndrome is associated with high mortality. Treatment of septic shock remains largely supportive of hemodynamics and tissue perfusion. Early changes in organ function assessed by the Sequential Organ Function Assessment (SOFA) score are highly predictive of the outcome. However, the individual patient's response to supportive therapy is very heterogeneous, and the mechanisms underlying this variable response remain elusive. The aim of the study was to investigate the transcriptome of whole blood in septic shock patients with different responses to early supportive hemodynamic therapy assessed by changes in SOFA scores within the first 48 h from intensive care unit (ICU) admission. METHODS: We performed whole blood RNA sequencing in 31 patients: 17 classified as responders (R) and 14 as non-responders (NR). Gene expression was investigated at ICU admission (time point 1, or T1), comparing R with NR [padj < 0.01; Benjamini-Hochberg (BH)] and over time from T1 to T2 (48 h later) in R and NR independently (paired analysis, padj < 0.01; BH). Then the differences in gene expression trends over time were evaluated (Mann-Whitney, P <0.01). To identify enriched biological processes, we performed an over-representation analysis based on a right-sided hypergeometric test with Bonferroni step-down as multiple testing correction (padj < 0.05). RESULTS: At ICU admission, we did not identify differentially expressed genes (DEGs) between the two groups. In the transition from T1 to T2, the activation of genes involved in T cell-mediated immunity, granulocyte and natural killer (NK) cell functions, and pathogen lipid clearance was noted in the R group. Genes involved in acute inflammation were downregulated in both groups. CONCLUSIONS: Within the limits of a small sample size, our results could suggest that early activation of genes of the adaptive immune response is associated with an improvement in organ function.

Transcriptome modulation by hydrocortisone in severe burn shock: ancillary analysis of a prospective randomized trial.

BACKGROUND: Despite shortening vasopressor use in shock, hydrocortisone administration remains controversial, with potential harm to the immune system. Few studies have assessed the impact of hydrocortisone on the transcriptional response in shock, and we are lacking data on burn shock. Our objective was to assess the hydrocortisone-induced transcriptional modulation in severe burn shock, particularly modulation of the immune response. METHODS: We collected whole blood samples during a randomized controlled trial assessing the efficacy of hydrocortisone administration in burn shock. Using whole genome microarrays, we first compared burn patients (n = 32) from the placebo group to healthy volunteers to describe the transcriptional modulation induced by burn shock over the first week. Then we compared burn patients randomized for either hydrocortisone administration or placebo, to assess hydrocortisone-induced modulation. RESULTS: Study groups were similar in terms of severity and major outcomes, but shock duration was significantly reduced in the hydrocortisone group. Many genes (n = 1687) were differentially expressed between burn patients and healthy volunteers, with 85% of them exhibiting a profound and persistent modulation over seven days. Interestingly, we showed that hydrocortisone enhanced the shock-associated repression of adaptive, but also innate immunity. CONCLUSIONS: We found that the initial host response to burn shock encompasses wide and persistent modulation of gene expression, with profound modulation of pathways associated with metabolism and immunity. Importantly, hydrocortisone administration may worsen the immunosuppression associated with severe injury. These data should be taken into account in the risk ratio of hydrocortisone administration in patients with inflammatory shock. TRIAL REGISTRATION: ClinicalTrials.gov, NCT00149123 . Registered on 6 September 2005.

Decreased CX3CR1 messenger RNA expression is an independent molecular biomarker of early and late mortality in critically ill patients.

BACKGROUND: Chemokine (C-X3-C motif) receptor 1 (CX3CR1) was identified as the most differentially expressed gene between survivors and non-survivors in two independent cohorts of septic shock patients and was proposed as a marker of sepsis-induced immunosuppression. Whether such a biomarker is associated with mortality in the heterogeneous group of critically ill patients is unknown. The primary objective of this study was to evaluate the association between CX3CR1 messenger RNA (mRNA) expression and mortality in intensive care unit (ICU) patients. The secondary objective was to evaluate similar endpoints in the subgroup of septic shock patients. METHODS: We performed a prospective, multicentre, non-interventional study in six ICUs of university hospitals in Lyon, France. Every consecutive adult patient with systemic inflammatory response syndrome and an expected length of stay in the ICU over 2 days was included. Whole-blood CX3CR1 mRNA expression was measured by quantitative real-time polymerase chain reaction at day 1 (D1) and D3 after inclusion. RESULTS: In ICU patients (n = 725), decreased CX3CR1 mRNA expression at D1 was associated with high D7 mortality (AUC 0.70, adjusted OR [aOR] 2.03, 95 % CI 1.19-3.46), while decreased expression at D3 was associated with increased D28 mortality (AUC 0.64, aOR 2.34, 95 % CI 1.45-3.77). In septic shock patients (n = 279), similar associations were observed between decreased D1 CX3CR1 mRNA expression and D7 mortality (AUC 0.69, aOR 2.76, 95 % CI 1.32-5.75) as well as decreased D3 expression and D28 mortality (AUC 0.72, aOR 3.98, 95 % CI 1.72-9.23). These associations were independent of lactacidaemia, Simplified Acute Physiology Score II, Sepsis-related Organ Failure Assessment score and Charlson comorbidity index. CONCLUSIONS: This study represents the largest evaluation of such an mRNA marker in a heterogeneous cohort of severely injured patients. Our results show that decreased CX3CR1 mRNA expression is associated with increased mortality in ICU patients. This suggests a link between injury-induced immunosuppression and mortality in critically ill patients. In this context, the monitoring of such a host response molecular biomarker could prove very helpful for the identification of patients at high risk of death in the ICU.

A strategy to build and validate a prognostic biomarker model based on RT-qPCR gene expression and clinical covariates.

BACKGROUND: Construction and validation of a prognostic model for survival data in the clinical domain is still an active field of research. Nevertheless there is no consensus on how to develop routine prognostic tests based on a combination of RT-qPCR biomarkers and clinical or demographic variables. In particular, the estimation of the model performance requires to properly account for the RT-qPCR experimental design. RESULTS: We present a strategy to build, select, and validate a prognostic model for survival data based on a combination of RT-qPCR biomarkers and clinical or demographic data and we provide an illustration on a real clinical dataset. First, we compare two cross-validation schemes: a classical outcome-stratified cross-validation scheme and an alternative one that accounts for the RT-qPCR plate design, especially when samples are processed by batches. The latter is intended to limit the performance discrepancies, also called the validation surprise, between the training and the test sets. Second, strategies for model building (covariate selection, functional relationship modeling, and statistical model) as well as performance indicators estimation are presented. Since in practice several prognostic models can exhibit similar performances, complementary criteria for model selection are discussed: the stability of the selected variables, the model optimism, and the impact of the omitted variables on the model performance. CONCLUSION: On the training dataset, appropriate resampling methods are expected to prevent from any upward biases due to unaccounted technical and biological variability that may arise from the experimental and intrinsic design of the RT-qPCR assay. Moreover, the stability of the selected variables, the model optimism, and the impact of the omitted variables on the model performances are pivotal indicators to select the optimal model to be validated on the test dataset.

Low-dose hydrocortisone reduces norepinephrine duration in severe burn patients: a randomized clinical trial.

INTRODUCTION: The aim of this study was to assess the effect of low-dose corticosteroid therapy in reducing shock duration after severe burn. METHODS: A placebo-controlled, double-blind, randomized clinical trial (RCT) was performed on two parallel groups in the burn intensive care unit (ICU). Patients were randomized to receive either low-dose corticosteroid therapy or placebo for seven days. A corticotropin test was performed at the time of randomization, before the administration of the treatment dose. Thirty-two severely burned patients with refractory shock (>0.5 µg/kg/min of norepinephrine) were prospectively included in the study. RESULTS: We included 12 patients in the hydrocortisone-treated group and 15 patients in the placebo group in the final analysis. Among these patients, 21 were nonresponders to the corticotropin test. Median norepinephrine treatment duration (primary objective) was significantly lower in the corticosteroid-treated versus the placebo group (57 hours versus 120 hours, P = 0.035). The number of patients without norepinephrine 72 hours after inclusion was significantly lower in the treated group (P = 0.003, log-rank test analysis). The total quantities of norepinephrine administered to patients were lower in the hydrocortisone-treated versus the placebo group (1,205 µg/kg (1,079 to 2,167) versus 1,971 µg/kg (1,535 to 3,893), P = 0.067). There was no difference in terms of ICU or hospital length of stay, sepsis incidence, cicatrization or mortality. CONCLUSIONS: In this placebo-controlled, randomized, double-blind clinical trial, we show for the first time that the administration of low-dose hydrocortisone in burn patients with severe shock reduces vasopressor administration. TRIAL REGISTRATION: Clinicaltrial.gov NCT00149123 . Registered 6 September 2005.

Decreased HLA-DR antigen-associated invariant chain (CD74) mRNA expression predicts mortality after septic shock.

INTRODUCTION: Septic syndromes remain the leading cause of mortality in intensive care units (ICU). Septic patients rapidly develop immune dysfunctions, the intensity and duration of which have been linked with deleterious outcomes. Decreased mRNA expressions of major histocompatibility complex (MHC) class II-related genes have been reported after sepsis. We investigated whether their mRNA levels in whole blood could predict mortality in septic shock patients. METHODS: A total of 93 septic shock patients were included. On the third day after shock, the mRNA expressions of five MHC class II-related genes (CD74, HLA-DRA, HLA-DMB, HLA-DMA, CIITA) were measured by qRT-PCR and monocyte human leukocyte antigen-DR (mHLA-DR) by flow cytometry. RESULTS: A significant correlation was found among MHC class II related gene expressions. Among mRNA markers, the best prognostic value was obtained for CD74 (HLA-DR antigen-associated invariant chain). For this parameter, the area under the receiver operating characteristic curve (AUC) was calculated (AUC = 0.67, 95% confidence interval (CI) = 0.55 to 0.79; P = 0.01) as well as the optimal cut-off value. After stratification based on this threshold, survival curves showed that a decreased CD74 mRNA level was associated with increased mortality after septic shock (Log rank test, P = 0.0043, Hazard Ratio = 3.0, 95% CI: 1.4 to 6.5). Importantly, this association remained significant after multivariate logistic regression analysis including usual clinical confounders (that is, severity scores, P = 0.026, Odds Ratio = 3.4, 95% CI: 1.2 to 9.8). CONCLUSION: Decreased CD74 mRNA expression significantly predicts 28-day mortality after septic shock. After validation in a larger multicentric study, this biomarker could become a robust predictor of death in septic patients.

Mortality Prediction in Sepsis With an Immune-Related Transcriptomics Signature: A Multi-Cohort Analysis.

Background: Novel biomarkers are needed to progress toward individualized patient care in sepsis. The immune profiling panel (IPP) prototype has been designed as a fully-automated multiplex tool measuring expression levels of 26 genes in sepsis patients to explore immune functions, determine sepsis endotypes and guide personalized clinical management. The performance of the IPP gene set to predict 30-day mortality has not been extensively characterized in heterogeneous cohorts of sepsis patients. Methods: Publicly available microarray data of sepsis patients with widely variable demographics, clinical characteristics and ethnical background were co-normalized, and the performance of the IPP gene set to predict 30-day mortality was assessed using a combination of machine learning algorithms. Results: We collected data from 1,801 arrays sampled on sepsis patients and 598 sampled on controls in 17 studies. When gene expression was assayed at day 1 following admission (1,437 arrays sampled on sepsis patients, of whom 1,161 were alive and 276 (19.2%) were dead at day 30), the IPP gene set showed good performance to predict 30-day mortality, with an area under the receiving operating characteristics curve (AUROC) of 0.710 (CI 0.652-0.768). Importantly, there was no statistically significant improvement in predictive performance when training the same models with all genes common to the 17 microarray studies (n = 7,122 genes), with an AUROC = 0.755 (CI 0.697-0.813, p = 0.286). In patients with gene expression data sampled at day 3 following admission or later, the IPP gene set had higher performance, with an AUROC = 0.804 (CI 0.643-0.964), while the total gene pool had an AUROC = 0.787 (CI 0.610-0.965, p = 0.811). Conclusion: Using pooled publicly-available gene expression data from multiple cohorts, we showed that the IPP gene set, an immune-related transcriptomics signature conveys relevant information to predict 30-day mortality when sampled at day 1 following admission. Our data also suggests that higher predictive performance could be obtained when assaying gene expression at later time points during the course of sepsis. Prospective studies are needed to confirm these findings using the IPP gene set on its dedicated measurement platform.

Recombinant human interleukin-7 reverses T cell exhaustion ex vivo in critically ill COVID-19 patients.

BACKGROUND: Lymphopenia is a hallmark of severe coronavirus disease 19 (COVID-19). Similar alterations have been described in bacterial sepsis and therapeutic strategies targeting T cell function such as recombinant human interleukin 7 (rhIL-7) have been proposed in this clinical context. As COVID-19 is a viral sepsis, the objectives of this study were to characterize T lymphocyte response over time in severe COVID-19 patients and to assess the effect of ex vivo administration of rhIL-7. RESULTS: Peripheral blood mononuclear cells from COVID-19 patients hospitalized in intensive care unit (ICU) were collected at admission and after 20 days. Transcriptomic profile was evaluated through NanoString technology. Inhibitory immune checkpoints expressions were determined by flow cytometry. T lymphocyte proliferation and IFN-γ production were evaluated after ex vivo stimulation in the presence or not of rhIL-7. COVID-19 ICU patients were markedly lymphopenic at admission. Mononuclear cells presented with inhibited transcriptomic profile prevalently with impaired T cell activation pathways. CD4 + and CD8 + T cells presented with over-expression of co-inhibitory molecules PD-1, PD-L1, CTLA-4 and TIM-3. CD4 + and CD8 + T cell proliferation and IFN-γ production were markedly altered in samples collected at ICU admission. These alterations, characteristic of a T cell exhaustion state, were more pronounced at ICU admission and alleviated over time. Treatment with rhIL-7 ex vivo significantly improved both T cell proliferation and IFN-γ production in cells from COVID-19 patients. CONCLUSIONS: Severe COVID-19 patients present with features of profound T cell exhaustion upon ICU admission which can be reversed ex vivo by rhIL-7. These results reinforce our understanding of severe COVID-19 pathophysiology and opens novel therapeutic avenues to treat such critically ill patients based of immunomodulation approaches. Defining the appropriate timing for initiating such immune-adjuvant therapy in clinical setting and the pertinent markers for a careful selection of patients are now warranted to confirm the ex vivo results described so far. Trial registration ClinicalTrials.gov identifier: NCT04392401 Registered 18 May 2020, http:// clinicaltrials.gov/ct2/show/NCT04392401.

T cell response against SARS-CoV-2 persists after one year in patients surviving severe COVID-19.

BACKGROUND: In critically ill COVID-19 patients, the initial response to SARS-CoV-2 infection is characterized by major immune dysfunctions. The capacity of these severe patients to mount a robust and persistent SARS-CoV-2 specific T cell response despite the presence of severe immune alterations during the ICU stay is unknown. METHODS: Critically ill COVID-19 patients were sampled five times during the ICU stay and 9 and 13 months afterwards. Immune monitoring included counts of lymphocyte subpopulations, HLA-DR expression on monocytes, plasma IL-6 and IL-10 concentrations, anti-SARS-CoV-2 IgG levels and T cell proliferation in response to three SARS-CoV-2 antigens. FINDINGS: Despite the presence of major lymphopenia and decreased monocyte HLA-DR expression during the ICU stay, convalescent critically ill COVID-19 patients consistently generated adaptive and humoral immune responses against SARS-CoV-2 maintained for more than one year after hospital discharge. Patients with long hospital stays presented with stronger anti-SARS-CoV-2 specific T cell response but no difference in anti-SARS-CoV2 IgG levels. INTERPRETATION: Convalescent critically ill COVID-19 patients consistently generated a memory immune response against SARS-CoV-2 maintained for more than one year after hospital discharge. In recovered individuals, the intensity of SARS-CoV-2 specific T cell response was dependent on length of hospital stay. FUNDING: This observational study was supported by funds from the Hospices Civils de Lyon, Fondation HCL, Claude Bernard Lyon 1 University and Région Auvergne Rhône-Alpes and by partial funding by REACTing (Research and ACTion targeting emerging infectious diseases) INSERM, France and a donation from Fondation AnBer (http://fondationanber.fr/).

Delayed increase of S100A9 messenger RNA predicts hospital-acquired infection after septic shock.

OBJECTIVE: Septic shock remains a serious disease with high mortality and increased risk of hospital-acquired infection. The prediction of outcome is of the utmost importance for selecting patients for therapeutic strategies aiming to modify the immune response. The aim of this study was to assess the capability of S100A9 messenger RNA in whole blood from patients with septic shock to predict survival and the occurrence of hospital-acquired infection. DESIGN: Cohort study. SETTING: Two intensive care units in a university hospital. SUBJECTS: The study included patients with septic shock (n = 166) and healthy volunteers (n = 44). INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: For the patients with septic shock patients, overall mortality was 38% and the mean Simplified Acute Physiologic Scale II on shock onset was 52. Using quantitative reverse transcriptase-polymerase chain reactions, we found that median S100A9 messenger RNA was significantly lower in healthy volunteers than in patients with septic shock (p < .0001) between days 1 and 3 after onset of the septic shock and not significantly different between nonsurvivor and survivor patients (p = .1278). However, median S100A9 messenger RNA measured on days 7-10 was significantly higher in patients who were about to contract hospital-acquired infections compared with those who were not (p = .009). In the multivariate analysis, the S100A9 marker increased the probability of contracting hospital-acquired infections with an odds ratio of 1.12 per unit (p = .0054). CONCLUSIONS: S100A9 messenger RNA is increased in septic shock and its delayed overexpression is associated with the occurrence of secondary hospital-acquired infection. This biomarker may be of major interest in identifying patients with increased risk of hospital-acquired infection who could benefit from targeted therapy aimed at restoring their immune functions.

Genome-wide comparison between IL-17A- and IL-17F-induced effects in human rheumatoid arthritis synoviocytes.

IL-17A is implicated in rheumatoid arthritis (RA) pathogenesis; however, the contribution of IL-17F remains to be clarified. Using microarrays and gene-specific expression assays, we compared the regulatory effects of IL-17A and IL-17F alone or in combination with TNF-alpha on RA synoviocytes. IL-17A and IL-17F expression was studied in osteoarthritis and RA synovium by immunohistochemistry. The comparison between the IL-17A and IL-17F stimulatory effect on RA synoviocytes was assessed at the protein level by ELISA and at the mRNA level by microarrays and real-time RT-PCR. TNFRII expression was studied by real-time RT-PCR and immunofluorescence, and neutralizing Ab was used to analyze its contribution to CCL20 secretion. IL-17A and IL-17F were detected in plasma cell-like cells from RA but not osteoarthritis synovium. In microarrays, IL-17A and IL-17F alone had similar regulatory effects, IL-17F being quantitatively less active. Both cytokines induced a similar expression pattern in the presence of TNF-alpha. Based on a cooperation index, 130 and 203 genes were synergistically induced by IL-17A or IL-17F plus TNF-alpha, respectively. Among these, the new target genes CXCR4, LPL, and IL-32 were validated by real-time RT-PCR. IL-17A and IL-17F up-regulated TNFRII expression, but had no effects on TNFRI, IL-17RA or IL-17RC. TNFRII blockade inhibited the synergistic induction of CCL20 by IL-17A or IL-17F and TNF-alpha. IL-17A and IL-17F are both expressed in RA synovium. In the presence of TNF-alpha, they induced a similar expression pattern in RA synoviocytes. Accordingly, IL-17F appears as a target in Th17-mediated diseases such as RA.

FoxO3a involved in neutrophil and T cell survival is overexpressed in rheumatoid blood and synovial tissue.

OBJECTIVE: FoxO3a is a transcriptional factor implicated in cell cycle regulation and apoptosis. Since rheumatoid arthritis (RA) is associated with apoptosis defects, the expression level, regulation and phosphorylation status of FoxO3a was investigated in blood and synovium from patients with RA. METHODS: In microarray experiments, an overexpression of FoxO3a mRNA was observed in blood from patients with RA compared with healthy controls. FoxO3a mRNA expression was quantified in polymorphonuclear cells (PMNs) and peripheral blood mononuclear cells from patients with RA by qRT-PCR. Total FoxO3a and phosphorylated FoxO3a (pFoxO3a) protein expression was analysed in blood leucocytes from patients with RA versus controls and in synovium from patients with RA versus patients with osteoarthritis (OA) by immunostaining. RESULTS: FoxO3a mRNA and protein expression levels were increased in blood from patients with RA compared with controls. FoxO3a overexpression was primarily observed in PMNs. In synovium from patients with RA, both total and inactive phosphorylated FoxO3a proteins were detected. FoxO3a was detected primarily in the sublining T lymphocytes of synovium from patients with RA compared with the lining layer tissue from patients with RA and OA, underlying a role for FoxO3a proteins in inflammation in RA. CONCLUSION: The overexpression of FoxO3a in blood from patients with RA, particularly in PMNs, suggests a potential role for this gene in the pathogenesis of RA through increased survival of blood PMNs. In synovium from patients with RA, FoxO3a mainly detected in inflammatory aggregates may also regulate the chronic survival of T lymphocytes.

Prognostic performance of endothelial biomarkers to early predict clinical deterioration of patients with suspected bacterial infection and sepsis admitted to the emergency department.

BACKGROUND: The objective of this study was to evaluate the ability of endothelial biomarkers to early predict clinical deterioration of patients admitted to the emergency department (ED) with a suspected sepsis. This was a prospective, multicentre, international study conducted in EDs. Adult patients with suspected acute bacterial infection and sepsis were enrolled but only those with confirmed infection were analysed. The kinetics of biomarkers and organ dysfunction were collected at T0, T6 and T24 hours after ED admission to assess prognostic performances of sVEGFR2, suPAR and procalcitonin (PCT). The primary outcome was the deterioration within 72 h and was defined as a composite of relevant outcomes such as death, intensive care unit admission and/or SOFA score increase validated by an independent adjudication committee. RESULTS: After adjudication of 602 patients, 462 were analysed including 124 who deteriorated (27%). On admission, those who deteriorated were significantly older (73 [60-82] vs 63 [45-78] y-o, p < 0.001) and presented significantly higher SOFA scores (2.15 ± 1.61 vs 1.56 ± 1.40, p = 0.003). At T0, sVEGFR2 (5794 [5026-6788] vs 6681 [5516-8059], p < 0.0001), suPAR (6.04 [4.42-8.85] vs 4.68 [3.50-6.43], p < 0.0001) and PCT (7.8 ± 25.0 vs 5.4 ± 17.9 ng/mL, p = 0.001) were associated with clinical deterioration. In multivariate analysis, low sVEGFR2 expression and high suPAR and PCT levels were significantly associated with early deterioration, independently of confounding parameters (sVEGFR2, OR = 1.53 [1.07-2.23], p < 0.001; suPAR, OR = 1.57 [1.21-2.07], p = 0.003; PCT, OR = 1.10 [1.04-1.17], p = 0.0019). Combination of sVEGFR2 and suPAR had the best prognostic performance (AUC = 0.7 [0.65-0.75]) compared to clinical or biological variables. CONCLUSIONS: sVEGFR2, either alone or combined with suPAR, seems of interest to predict deterioration of patients with suspected bacterial acute infection upon ED admission and could help front-line physicians in the triage process.

Early kinetics of the transcriptional response of human leukocytes to staphylococcal superantigenic enterotoxins A and G.

The severity of Staphylococcus aureus sepsis is positively associated with staphylococcal enterotoxin A (SEA) and negatively associated with the enterotoxin gene cluster (egc), which encodes five staphylococcal enterotoxins (SE). It was recently demonstrated that SE can induce human leukocytes to release inflammatory mediators. Contrary to SEG (one of the five egc superantigens), SEA induces a strong proinflammatory/Th1 response, including tumor necrosis factor-alpha and macrophage inflammatory protein-1 alpha production. Here, we investigated the very early transcriptional response of human PBMC to these two SEs. We confirm that SEA is more potent than SEG. Importantly, our data also suggest that the early response to SE is likely induced more by T cells than by monocytes. In addition, negative feedback control is triggered at the same time as proinflammatory processes (inflammation and apoptosis). It confirms at the molecular level new models of sepsis pathophysiology as concomitant and opposite sides of a given mechanism participating to response to bacterial compound are both necessary. This preliminary study highlights the potential of transcriptional studies for unraveling the very early mechanisms of leukocyte responses to SE. Further studies are needed to understand the mechanisms underlying the putative synergy between SE and other bacterial components.

Modulation of LILRB2 protein and mRNA expressions in septic shock patients and after ex vivo lipopolysaccharide stimulation.

Septic patients develop immune dysfunctions, the intensities and durations of which are associated with deleterious outcomes. LILRB2 (leukocyte immunoglobulin-like receptors subfamily B, member 2), an inhibitory member of the LILR family of receptors, is known for its immunoregulatory properties. In a microarray study, we identified LILRB2 as an upregulated gene in septic shock patients. On monocytes primed with LPS ex vivo, LILRB2 mRNA and protein expressions were dose-dependently downregulated and subsequently highly upregulated versus non-stimulated cells. This is concordant with clinical data, since both LILRB2 mRNA and protein expressions were significantly increased in septic shock patients at day 3. In a cohort of more than 700 patients, only after septic shock were LILRB2 mRNA levels increased compared with non-infected or less severely infected patients. This was preceded by a phase of downregulated mRNA expression during the first hours after septic shock. Interestingly, the intensity of this decrease was associated with increased risk of death after septic shock. LILRB2 protein and mRNA expressions are deregulated on monocytes after septic shock and this can be reproduced ex vivo after LPS challenge. Considering LILRB2 inhibitory properties, we can hypothesize that LILRB2 may participate in the altered immune response after septic shock.

Association between mRNA expression of CD74 and IL10 and risk of ICU-acquired infections: a multicenter cohort study.

PURPOSE: Intensive care unit (ICU)-acquired infections (IAI) result in increased hospital and ICU stay, costs and mortality. To date, no biomarker has shown sufficient evidence and ease of application in clinical routine for the identification of patients at risk of IAI. We evaluated the association of the systemic mRNA expression of two host response biomarkers, CD74 and IL10, with IAI occurrence in a large cohort of ICU patients. METHODS: ICU patients were prospectively enrolled in a multicenter cohort study. Whole blood was collected on the day of admission (D1) and on day 3 (D3) and day 6 (D6) after admission. Patients were screened daily for IAI occurrence and data were censored after IAI diagnosis. mRNA expression levels of biomarkers were measured using RT-qPCR. Fine and Gray competing risk models were used to assess the association between gene expression and IAI occurrence. RESULTS: A total of 725 patients were analyzed. At least one IAI episode occurred in 137 patients (19%). After adjustment for shock and sepsis status at admission, CD74 and IL10 levels were found to be significantly associated with IAI occurrence [subdistribution hazard ratio (95% confidence interval) 0.67 (0.46-0.97) for CD74 D3/D1 expression ratio and 2.21 (1.63-3.00) for IL10 at D3]. IAI cumulative incidence was significantly different between groups stratified according to CD74 or IL10 expression (Gray tests p < 0.001). CONCLUSION: Our results suggest that two immune biomarkers, CD74 and IL10, could be relevant tools for the identification of IAI risk in ICU patients.

Lack of association of IL-10 promoter gene variants with type 1 diabetes in a French population.

Although genetic predisposition to type 1 diabetes shows a strong association with human leukocyte antigen (HLA) class II alleles, additional genes may influence the immune process and the progression of beta cell loss. Preliminary reports suggested that IL-10 gene polymorphisms contribute to susceptibility to type 1 diabetes. We analyzed the frequencies of three main variants of the promoter region of the IL-10 gene at the positions -1082, -819, and -592 in a cohort of 358 type 1 diabetic patients representing the same regional population pattern and 519 controls from the same region using an enzyme-linked oligonucleotide sorbent assay. We did not find any statistical association in the entire cohort or after stratification for high-risk HLA-DQ alleles. However, the IL-10 -1082 polymorphism was significantly associated with GAD and IA-2 antibodies at clinical onset. Such polymorphism is known to be associated with the reduction of secreted IL-10 which may support the concept of accelerated Th-1 T-cell reactivity. In conclusion, IL-10 promoter gene variants may contribute, but to a minor extent, to disease susceptibility in juvenile type 1 diabetes and should not be included in the routine genetic screening of high-risk individuals.

Identification of CD177 as the most dysregulated parameter in a microarray study of purified neutrophils from septic shock patients.

Sepsis represents the host's systemic inflammatory response to an infection. In this condition, immune response associates a marked inflammatory response and the delayed development of severe dysfunctions affecting both innate and adaptive responses. As neutrophils are the first line of defense against infection, they are central to the pathophysiology of sepsis in first hours. Nevertheless, their role during immunosuppression phase remains elusive. The main objective of the current work was to perform a transcriptomic study on purified neutrophils from septic shock patients (n=9) so as to identify genes that are differentially expressed during the first week after disease onset both (3-4 and 6-8days) versus healthy donors. Then, 45 septic shock patients were prospectively enrolled to confirm results at the protein level using flow cytometry. Twenty healthy volunteers (HV) were also included for the whole study. By comparing the transcriptome of purified neutrophils, we identified 364 up-regulated and 328 down-regulated genes differentially expressed. Of them, CD177 mRNA, coding for an activation molecule in chemotaxis, had the highest fold change modulation between patients and HV. This increase was then confirmed at the protein level. There was a constant subset of neutrophils that did not express CD177. However, when positive, septic neutrophils presented with significantly increased CD177 expression. Of note, no association between CD177 overexpression and features of immunosuppression has been highlighted. In addition, this up-regulation was negatively correlated with a decreased expression of CD10, a characteristic of immature myeloid cells. In conclusion, in this exploratory work, we shed light on the increased CD177 mRNA and protein expressions in circulating neutrophils after septic shock. Considering the potential dual roles of CD177 neutrophil (i.e., maturation/chemotaxis), negatively correlated in this study, its participation in septic shock pathophysiology deserves further investigation. Furthermore, its potential as a biomarker for sepsis would deserve to be investigated in large cohorts of patients.