Immune profiling of critically ill patients with acute kidney injury during the first week after various types of injuries: the REALAKI study.

BACKGROUND: Acute kidney injury (AKI) is common in hospitalized patients and results in significant morbidity and mortality. The objective of the study was to explore the systemic immune response of intensive care unit patients presenting with AKI, especially the association between immune profiles and persistent AKI during the first week after admission following various types of injuries (sepsis, trauma, surgery, and burns). METHODS: REALAKI is an ancillary analysis of the REAnimation Low Immune Status Marker (REALISM) cohort study, in which 359 critically ill patients were enrolled in three different intensive care units. Patients with end-stage renal disease were excluded from the REALAKI study. Clinical samples and data were collected three times after admission: at day 1 or 2 (D1-2), day 3 or 4 (D3-4) and day 5, 6 or 7 (D5-7). Immune profiles were compared between patients presenting with or without AKI. Patients with AKI at both D1-2 and D5-7 were defined as persistent AKI. A multivariable logistic regression model was performed to determine the independent association between AKI and patients' immunological parameters. RESULTS: Three hundred and fifty-nine patients were included in this analysis. Among them, 137 (38%) were trauma patients, 103 (29%) post-surgery patients, 95 (26%) sepsis patients, and 24 (7%) were burn patients. One hundred and thirty-nine (39%) patients presented with AKI at D1-2 and 61 (20%) at D5-7. Overall, 94% presented with persistent AKI at D5-7. Patients with AKI presented with increased pro and anti-inflammatory cytokines and altered innate and adaptive immune responses. The modifications observed in the immune profiles tended to be more pronounced with increasing KDIGO stages. In the logistic regression model, a statistically significant association was observed at D1-2 between AKI and CD10lowCD16low immature neutrophils (OR 3.03 [1.7-5.5]-p < 0.001). At D5-7, increased interleukin-10 (IL-10) levels and reduced ex vivo TNF-α production after LPS stimulation were significantly associated with the presence of AKI (OR 1.38 [1.12-1.71]-p = 0.001 and 0.51 [0.27-0.91]-p = 0.03, respectively). Patients who recovered from AKI between D1-2 and D5-7 compared to patients with persistent AKI at D5-7, tended to correct these alterations. CONCLUSION: Following various types of severe injuries, early AKI is associated with the initial inflammatory response. Presence of AKI at the end of the first week after injury is associated with injury-induced immunosuppression.

Integrated clustering of multiple immune marker trajectories reveals different immunotypes in severely injured patients.

BACKGROUND: The immune response of critically ill patients, such as those with sepsis, severe trauma, or major surgery, is heterogeneous and dynamic, but its characterization and impact on outcomes are poorly understood. Until now, the primary challenge in advancing our understanding of the disease has been to concurrently address both multiparametric and temporal aspects. METHODS: We used a clustering method to identify distinct groups of patients, based on various immune marker trajectories during the first week after admission to ICU. In 339 severely injured patients, we initially longitudinally clustered common biomarkers (both soluble and cellular parameters), whose variations are well-established during the immunosuppressive phase of sepsis. We then applied this multi-trajectory clustering using markers composed of whole blood immune-related mRNA. RESULTS: We found that both sets of markers revealed two immunotypes, one of which was associated with worse outcomes, such as increased risk of hospital-acquired infection and mortality, and prolonged hospital stays. This immunotype showed signs of both hyperinflammation and immunosuppression, which persisted over time. CONCLUSION: Our study suggest that the immune system of critically ill patients can be characterized by two distinct longitudinal immunotypes, one of which included patients with a persistently dysregulated and impaired immune response. This work confirms the relevance of such methodology to stratify patients and pave the way for further studies using markers indicative of potential immunomodulatory drug targets.

Immune Profiling Panel Gene Set Identifies Critically Ill Patients With Low Monocyte Human Leukocyte Antigen-DR Expression: Preliminary Results From the REAnimation Low Immune Status Marker (REALISM) Study.

OBJECTIVES: There is a crucial unmet need for biomarker-guided diagnostic and prognostic enrichment in clinical trials evaluating immune modulating therapies in critically ill patients. Low monocyte expression of human leukocyte antigen-DR (mHLA-DR), considered as a reference surrogate to identify immunosuppressed patients, has been proposed for patient stratification in immunostimulation approaches. However, its widespread use in clinic has been somewhat hampered by technical constraints inherent to flow cytometry technology. The objective of the present study was to evaluate the ability of a prototype multiplex polymerase chain reaction tool (immune profiling panel [IPP]) to identify immunosuppressed ICU patients characterized by a low mHLA-DR expression. DESIGN: Retrospective observational cohort study. SETTING: Adult ICU in a University Hospital, Lyon, France. PATIENTS: Critically ill patients with various etiologies enrolled in the REAnimation Low Immune Status Marker study (NCT02638779). INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: mHLA-DR and IPP data were obtained from 1,731 blood samples collected from critically ill patients with various etiologies and healthy volunteers. A partial least square regression model combining the expression levels of IPP markers was trained and used for the identification of samples from patients presenting with evidence of immunosuppression, defined here as mHLADR less than 8,000 antibodies bound per cell (AB/C). The IPP gene set had an area under the receiver operating characteristic curve (AUC) of 0.86 (95% CI 0.83-0.89) for the identification of immunosuppressed patients. In addition, when applied to the 123 patients still in the ICU at days 5-7 after admission, IPP similarly enriched the number of patients with ICU-acquired infections in the immunosuppressed group (26%), in comparison with low mHLA-DR (22%). CONCLUSIONS: This study reports on the potential of the IPP gene set to identify ICU patients presenting with mHLA-DR less than 8,000 AB/C. Upon further optimization and validation, this molecular tool may help in the stratification of patients that could benefit from immunostimulation in the context of personalized medicine.

Economic burden of in-hospital AKI: a one-year analysis of the nationwide French hospital discharge database.

BACKGROUND: Although Acute Kidney Injury (AKI) incidence is increasing worldwide, data investigating its cost are lacking. This population-wide study aimed to describe the characteristics and costs of hospital stays with, and without AKI, and to estimate the AKI-associated increases in costs and length of stay (LOS) in three subgroups (major open visceral surgery (MOV), cardiovascular surgery with extracorporeal circulation (CVEC), and sepsis). METHODS: All hospital stays that occurred in France in 2018 were included. Stay and patient characteristics were collected in the French hospital discharge database and described. Medical conditions were identified using the 10th International Classification of Diseases and the medical acts classification. In each subgroup, the adjusted increase in cost and LOS associated with AKI was estimated using a generalized linear model with gamma distribution and a log link function. RESULTS: 26,917,832 hospital stays, of which 415,067 (1.5%) with AKI, were included. AKI was associated with 83,553 (19.8%), 7,165 (17.9%), and 15,387 (9.2%) of the stays with sepsis, CVEC, and MOV, respectively. Compared to stays without AKI, stays with AKI were more expensive (median [IQR] €4,719[€2,963-€7782] vs. €735[€383-€1,805]) and longer (median [IQR] 9[4-16] vs. 0[0-2] days). AKI was associated with a mean [95%CI] increase in hospitalization cost of 70% [69;72], 48% [45;50], and 68% [65;70] in the sepsis, CVEC, and MOV groups respectively, after adjustment. CONCLUSION: This study confirms the major economic burden of in-hospital AKI in a developed country. Interventions to prevent AKI are urgently needed and their cost should be balanced with AKI-related costs.

Immune Profiling Demonstrates a Common Immune Signature of Delayed Acquired Immunodeficiency in Patients With Various Etiologies of Severe Injury.

OBJECTIVES: The host response plays a central role in the pathophysiology of sepsis and severe injuries. So far, no study has comprehensively described the overtime changes of the injury-induced immune profile in a large cohort of critically ill patients with different etiologies. DESIGN: Prospective observational cohort study. SETTING: Adult ICU in a University Hospital in Lyon, France. PATIENTS: Three hundred fifty-three septic, trauma, and surgical patients and 175 healthy volunteers were included in the REAnimation Low Immune Status Marker study. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Extensive immune profiling was performed by assessing cellular phenotypes and functions, protein, and messenger RNA levels at days 1-2, 3-4, and 5-7 after inclusion using a panel of 30 standardized immune markers. Using this immunomonitoring panel, no specificity in the immune profile was observed among septic, trauma, and surgical patients. This common injury-induced immune response was characterized by an initial adaptive (i.e., physiologic) response engaging all constituents of the immune system (pro- and anti-inflammatory cytokine releases, and innate and adaptive immune responses) but not associated with increased risk of secondary infections. In contrary, the persistence in a subgroup of patients of profound immune alterations at the end of the first week after admission was associated with increased risk of secondary infections independently of exposure to invasive devices. The combined monitoring of markers of pro-/anti-inflammatory, innate, and adaptive immune responses allowed a better enrichment of patients with risk of secondary infections in the selected population. CONCLUSIONS: Using REAnimation Low Immune Status Marker immunomonitoring panel, we detected delayed injury-acquired immunodeficiency in a subgroup of severely injured patients independently of primary disease. Critically ill patients' immune status could be captured through the combined monitoring of a common panel of complementary markers of pro-/anti-inflammatory, innate, and adaptive immune responses. Such immune monitoring needs to be incorporated in larger study cohorts with more extensive immune surveillance to develop specific hypothesis allowing for identification of biological systems affecting altered immune function related to late infection in the setting of acute systemic injury.

Clinical Outcomes of Persistent Severe Acute Kidney Injury among Patients with Kidney Disease Improving Global Outcomes Stage 2 or 3 Acute Kidney Injury.

INTRODUCTION: The burden of persistent (≥3 days) severe AKI (PS-AKI) is poorly described among inpatients with stage 2-3 AKI in the ward or ICU. Quantification could motivate targeted interventions to decrease duration of AKI in these high-risk patients. METHODS: This retrospective cohort study included adult patients discharged from January 1, 2017, to December 31, 2019, from US hospitals in the PINC AI Healthcare Database. Patients with KDIGO stage 2 or 3 AKI, length of stay ≥3 days, ≥3 serum creatinine measures, and no history of renal transplant, dialysis, or stage 5 chronic kidney disease were included. Patients were classified as PS-AKI (stage 3 AKI lasting ≥3 days or with death in ≤3 days, or stage 2 or 3 AKI with dialysis in ≤3 days) or not PS-AKI (NPS-AKI) (stage 3 AKI for ≤2 days, or stage 2 AKI without dialysis in ≤3 days). Outcomes during index (initial) hospitalization were PS-AKI incidence, ICU use, and in-hospital mortality, and during 30 days post-discharge were readmissions, in-hospital mortality, dialysis, and "new" dialysis (dialysis among patients without dialysis during index hospitalization). For index outcomes, we used a sensitivity definition, PS-AKISens, that excluded patients who met PS-AKI criteria by dialysis/death in ≤3 days of AKI onset. Multivariable-adjusted logistic regression quantified differences between PS-AKI and NPS-AKI, overall, and separately for ICU and non-ICU patients. RESULTS: Among 126,528 inpatients with stage 2 or 3 AKI, PS-AKI developed in 24.4% (30,916), with 39% of PS-AKI occurring in non-ICU patients. With NPS-AKI as the reference group, adjusted odds ratios (aORs) (95% CI) for PS-AKI and for PS-AKISens were 2.15 (2.09-2.21) and 1.28 (1.24-1.32) for ICU use and 4.58 (4.41-4.75) and 1.79 (1.70-1.89) for in-hospital mortality during index hospitalization. For outcomes during 30 days post-discharge, aORs for PS-AKI versus NPS-AKI were 1.07 (1.02-1.11) for readmissions, 1.33 (1.18-1.49) for in-hospital mortality, 15.66 (13.87-17.67) for dialysis, and 6.80 (5.84-7.93) for new dialysis. Despite higher mortality among ICU patients, aORs for outcomes during index and 30 days post-discharge were similar for ICU and non-ICU patients. CONCLUSION: In and out of the ICU, PS-AKI frequently affected inpatients with stage 2 or 3 AKI and was independently associated with worse clinical outcomes during index hospitalization and during 30 days post-discharge. These results suggest that interventions to prevent persistence of severe AKI may reduce adverse clinical outcomes among patients with stage 2 or 3 AKI in or out of the ICU.

Human Respiratory Syncytial Virus-Induced Immune Signature of Infection Revealed by Transcriptome Analysis of Clinical Pediatric Nasopharyngeal Swab Samples.

Human respiratory syncytial virus (HRSV) constitutes one the main causes of respiratory infection in neonates and infants worldwide. Transcriptome analysis of clinical samples using high-throughput technologies remains an important tool to better understand virus-host complex interactions in the real-life setting but also to identify new diagnosis/prognosis markers or therapeutics targets. A major challenge when exploiting clinical samples such as nasal swabs, washes, or bronchoalveolar lavages is the poor quantity and integrity of nucleic acids. In this study, we applied a tailored transcriptomics workflow to exploit nasal wash samples from children who tested positive for HRSV. Our analysis revealed a characteristic immune signature as a direct reflection of HRSV pathogenesis and highlighted putative biomarkers of interest such as IP-10, TMEM190, MCEMP1, and TIMM23.

RNA-Seq Transcriptome Analysis Reveals Long Terminal Repeat Retrotransposon Modulation in Human Peripheral Blood Mononuclear Cells after In Vivo Lipopolysaccharide Injection.

Human endogenous retroviruses (HERVs) and mammalian apparent long terminal repeat (LTR) retrotransposons (MaLRs) are retroviral sequences that integrated into germ line cells millions of years ago. Transcripts of these LTR retrotransposons are present in several tissues, and their expression is modulated in pathological conditions, although their function remains often far from being understood. Here, we focused on the HERV/MaLR expression and modulation in a scenario of immune system activation. We used a public data set of human peripheral blood mononuclear cells (PBMCs) RNA-Seq from 15 healthy participants to a clinical trial before and after exposure to lipopolysaccharide (LPS), for which we established an RNA-Seq workflow for the identification of expressed and modulated cellular genes and LTR retrotransposon elements.IMPORTANCE We described the HERV and MaLR transcriptome in PBMCs, finding that about 8.4% of the LTR retrotransposon loci were expressed and identifying the betaretrovirus-like HERVs as those with the highest percentage of expressed loci. We found 4,607 HERV and MaLR loci that were modulated as a result of in vivo stimulation with LPS. The HERV-H group showed the highest number of differentially expressed most intact proviruses. We characterized the HERV and MaLR loci as differentially expressed, checking their genomic context of insertion and observing a general colocalization with genes that are involved and modulated in the immune response, as a consequence of LPS stimulation. The analyses of HERV and MaLR expression and modulation show that these LTR retrotransposons are expressed in PBMCs and regulated in inflammatory settings. The similar regulation of HERVs/MaLRs and genes after LPS stimulation suggests possible interactions of LTR retrotransposons and the immune host response.

Static compliance of the respiratory system in COVID-19 related ARDS: an international multicenter study.

BACKGROUND: Controversies exist on the nature of COVID-19 related acute respiratory distress syndrome (ARDS) in particular on the static compliance of the respiratory system (Crs). We aimed to analyze the association of Crs with outcome in COVID-19-associated ARDS, to ascertain its determinants and to describe its evolution at day-14. METHODS: In this observational multicenter cohort of patients with moderate to severe Covid-19 ARDS, Crs was measured at day-1 and day-14. Association between Crs or Crs/ideal body weight (IBW) and breathing without assistance at day-28 was analyzed with multivariable logistic regression. Determinants were ascertained by multivariable linear regression. Day-14 Crs was compared to day-1 Crs with paired t-test in patients still under controlled mechanical ventilation. RESULTS: The mean Crs in 372 patients was 37.6 ± 13 mL/cmH2O, similar to as in ARDS of other causes. Multivariate linear regression identified chronic hypertension, low PaO2/FiO2 ratio, low PEEP, and low tidal volume as associated with lower Crs/IBW. After adjustment on confounders, nor Crs [OR 1.0 (CI 95% 0.98-1.02)] neither Crs/IBW [OR 0.63 (CI 95% 0.13-3.1)] were associated with the chance of breathing without assistance at day-28 whereas plateau pressure was [OR 0.93 (CI 95% 0.88-0.99)]. In a subset of 108 patients, day-14 Crs decreased compared to day-1 Crs (31.2 ± 14.4 mL/cmH2O vs 37.8 ± 11.4 mL/cmH2O, p < 0.001). The decrease in Crs was not associated with day-28 outcome. CONCLUSION: In a large multicenter cohort of moderate to severe COVID-19 ARDS, mean Crs was decreased below 40 mL/cmH2O and was not associated with day-28 outcome. Crs decreased between day-1 and day-14 but the decrease was not associated with day-28 outcome.

Immune Profiling Panel: A Proof-of-Concept Study of a New Multiplex Molecular Tool to Assess the Immune Status of Critically Ill Patients.

BACKGROUND: Critical illness such as sepsis is a life-threatening syndrome defined as a dysregulated host response to infection and is characterized by patients exhibiting impaired immune response. In the field of diagnosis, a gap still remains in identifying the immune profile of critically ill patients in the intensive care unit (ICU). METHODS: A new multiplex immune profiling panel (IPP) prototype was assessed for its ability to semiquantify messenger RNA immune-related markers directly from blood, using the FilmArray System, in less than an hour. Samples from 30 healthy volunteers were used for the technical assessment of the IPP tool. Then the tool was clinically assessed using samples from 10 healthy volunteers and 20 septic shock patients stratified using human leukocyte antigen-DR expression on monocytes (mHLA-DR). RESULTS: The IPP prototype consists of 16 biomarkers that target the immune response. The majority of the assays had a linear expression with different RNA inputs and a coefficient of determination (R2) > 0.8. Results from the IPP pouch were comparable to standard quantitative polymerase chain reaction and the assays were within the limits of agreement in Bland-Altman analysis. Quantification cycle values of the target genes were normalized against reference genes and confirmed to account for the different cell count and technical variability. The clinical assessment of the IPP markers demonstrated various gene modulations that could distinctly differentiate 3 profiles: healthy volunteers, intermediate mHLA-DR septic shock patients, and low mHLA-DR septic shock patients. CONCLUSIONS: The use of IPP showed great potential for the development of a fully automated, rapid, and easy-to-use immune profiling tool. The IPP tool may be used in the future to stratify critically ill patients in the ICU according to their immune status. Such stratification will enable personalized management of patients and guide treatments to avoid secondary infections and lower mortality.

Towards standardization of immune functional assays.

Recent advances in the immunotherapy field require evaluation of the immune function to adapt therapeutic decisions. Immune functional assays (IFA) are able to reveal the immune status and would be useful to further adapt and/or improve patient's care. However, standardized methods are needed to implement IFA in clinical settings. We carried out an independent validation of a published method used to characterize the underlying host response to infectious conditions using an IFA. We evaluated the reproducibility and robustness of this IFA and the associated readout using an independent healthy volunteers (HV) cohort. Expression of a 44-gene signature and IFNγ protein secretion was assessed after stimulation. We observed a strong host-response correlation between the two cohorts. We also highlight that standardized methods for immune function evaluation exist and could be implemented in larger-scale studies. This IFA could be a relevant tool to reveal innate and adaptive immune dysfunction in immune-related disorders patients.

Diagnostic and medical needs for therapeutic drug monitoring of antibiotics.

Therapeutic drug monitoring (TDM) of antibiotics has been practiced for more than half a century, but it is still not widely applied for infected patients. It has a traditional focus on limiting toxicity of specific classes of antibiotics such as aminoglycosides and vancomycin. With more patients in critical care with higher levels of sickness severity and immunosuppression as well as an increasingly obese and ageing population, an increasing risk of suboptimal antibiotic exposure continues to escalate. As such, the value of TDM continues to expand, especially for beta-lactams which constitute the most frequently used antibiotic class. To date, the minimum inhibitory concentration (MIC) of infectious microbes rather than classification in terms of susceptible and resistant can be reported. In parallel, increasingly sophisticated TDM technology is becoming available ensuring that TDM is feasible and can deliver personalized antibiotic dosing schemes. There is an obvious need for extensive studies that will quantify the improvements in clinical outcome of individual TDM-guided dosing. We suggest that a broad diagnostic and medical investigation of the TDM arena, including market analyses and analytical technology assessment, is a current priority.

Septic Shock Shapes B Cell Response toward an Exhausted-like/Immunoregulatory Profile in Patients.

Septic shock is accompanied by the development of immune dysfunctions whose intensity and duration are associated with increased risk of secondary infections and mortality. Although B lymphocytes play a pivotal role in the immune response to infections, no comprehensive exploration of circulating B cell status has been performed during the immunosuppressive phase of septic shock. Thus, our aim was to extensively characterize the phenotype and function of B cells in septic shock, including IL-10 production. Circulating B lymphocyte phenotype and function were evaluated by flow cytometry on fresh whole blood and after ex vivo stimulation in adult septic shock patients sampled at day 1, 3, and 6 after the onset of shock. The circulating B cell number was reduced in septic shock patients, whereas the B cell proportion among total lymphocytes was increased. The remaining circulating B lymphocytes presented with decreased MHC class II expression and increased CD21low CD95high exhausted-like phenotype but showed no change in maturation status. Circulating B cell functions were markedly altered after sepsis with reduced ex vivo activation and proliferation capacities. Finally, B cell response after septic shock was characterized by a clear plasmacytosis and an increased IL-10 production in remaining B cells from patients after ex vivo stimulation. During the sepsis-induced immunosuppression phase, B cell response is altered and is oriented toward an exhausted-like/immunoregulatory profile. Further studies are now needed to confirm the immunoregulatory properties of B lymphocytes and evaluate their role in sepsis-induced immunosuppression.

Dynamic LTR retrotransposon transcriptome landscape in septic shock patients.

BACKGROUND: Sepsis is defined as a life-threatening organ dysfunction caused by a dysregulated host response to infection. Numerous studies have explored the complex and dynamic transcriptome modulations observed in sepsis patients, but a large fraction of the transcriptome remains unexplored. This fraction could provide information to better understand sepsis pathophysiology. Multiple levels of interaction between human endogenous retroviruses (HERV) and the immune response have led us to hypothesize that sepsis is associated with HERV transcription and that HERVs may contribute to a signature among septic patients allowing stratification and personalized management. METHODS: We used a high-density microarray and RT-qPCR to evaluate the HERV and Mammalian Apparent Long Terminal Repeat retrotransposons (MaLR) transcriptome in a pilot study that included 20 selected septic shock patients, stratified on mHLA-DR expression, with samples collected on day 1 and day 3 after inclusion. We validated the results in an unselected, independent cohort that included 100 septic shock patients on day 3 after inclusion. We compared septic shock patients, according to their immune status, to describe the transcriptional HERV/MaLR and conventional gene expression. For differential expression analyses, moderated t tests were performed and Wilcoxon signed-rank tests were used to analyze RT-qPCR results. RESULTS: We showed that 6.9% of the HERV/MaLR repertoire was transcribed in the whole blood, and septic shock was associated with an early modulation of a few thousand of these loci, in comparison to healthy volunteers. We provided evidence that a subset of HERV/MaLR and conventional genes were differentially expressed in septic shock patients, according to their immune status, using monocyte HLA-DR (mHLA-DR) expression as a proxy. A group of 193 differentially expressed HERV/MaLR probesets, tested in an independent septic shock cohort, identified two groups of patients with different immune status and severity features. CONCLUSION: We demonstrated that a large, unexplored part of our genome, which codes for HERV/MaLR, may be linked to the host immune response. The identified set of HERV/MaLR probesets should be evaluated on a large scale to assess the relevance of these loci in the stratification of septic shock patients. This may help to address the heterogeneity of these patients.

Circulating dipeptidyl peptidase-3 at admission is associated with circulatory failure, acute kidney injury and death in severely ill burn patients.

BACKGROUND: Dipeptidyl peptidase-3 (DPP3) is a metallopeptidase which cleaves bioactive peptides, notably angiotensin II, and is involved in inflammation regulation. DPP3 has been proposed to be a myocardial depressant factor and to be involved in circulatory failure in acute illnesses, possibly due to angiotensin II cleavage. In this study, we evaluated the association between plasmatic DPP3 level and outcome (mortality and hemodynamic failure) in severely ill burn patients. METHODS: In this biomarker analysis of a prospective cohort study, we included severely ill adult burn patients in two tertiary burn intensive care units. DPP3 was measured at admission (DPP3admin) and 3 days after. The primary endpoint was 90-day mortality. Secondary endpoints were hemodynamic failure and acute kidney injury (AKI). RESULTS: One hundred and eleven consecutive patients were enrolled. The median age was 48 (32.5-63) years, with a median total body surface area burned of 35% (25-53.5) and Abbreviated Burn Severity Index (ABSI) of 8 (7-11). Ninety-day mortality was 32%. The median DPP3admin was significantly higher in non-survivors versus survivors (53.3 ng/mL [IQR 28.8-103.5] versus 27.1 ng/mL [IQR 19.4-38.9]; p < 0.0001). Patients with a sustained elevated DPP3 had an increased risk of death compared to patients with high DPP3admin but decreased levels on day 3. Patients with circulatory failure had higher DPP3admin (39.2 ng/mL [IQR 25.9-76.1] versus 28.4 ng/mL [IQR 19.8-39.6]; p = 0.001) as well as patients with AKI (49.7 ng/mL [IQR 30.3-87.3] versus 27.6 ng/mL [IQR 19.4-41.4]; p = 0.001). DPP3admin added prognostic value on top of ABSI (added chi2 12.2, p = 0.0005), Sequential Organ Failure Assessment (SOFA) score at admission (added chi2 4.9, p = 0.0268), and plasma lactate at admission (added chi2 6.9, p = 0.0086) to predict circulatory failure within the first 48 h. CONCLUSIONS: Plasma DPP3 concentration at admission was associated with an increased risk of death, circulatory failure, and AKI in severely burned patients. Whether DPP3 plasma levels could identify patients who would respond to alternative hemodynamic support strategies, such as intravenous angiotensin II, should be explored.

Outcome and characteristics of invasive fungal infections in critically ill burn patients: A multicenter retrospective study.

BACKGROUND: Characteristics and outcome of invasive fungal infection (IFI) in critically ill burn patients have been poorly explored. OBJECTIVES: We report the factors associated with 90-day mortality in a multicentre retrospective European study. PATIENTS/METHODS: All burn patients with confirmed IFI admitted between 1 January 2010 to 31 December 2015 in 10 centres in France and Belgium were included. RESULTS: Ninety-four patients were enrolled with 110 cases of IFIs: 79 (71.8%) were yeasts IFI and 31 (28.2%) filamentous IFI. Incidence was 1% among admitted patients. The 90-day mortality was 37.2% for all IFIs combined, 52% for filamentous infection and 31.9% for yeast infection. Patients with more than one IFI had a higher 90-day mortality than patients with only one episode (61.5% vs 33.5% (P = .006)). In multivariate analysis, higher Simplified Acute Physiology Score II (OR = 1.05 (95% CI: 1.02-1.09) P = .003), bacterial co-infection (OR = 3.85 (95% CI: 1.23-12.01), P = .014) and use of skin allografts at the time of IFI diagnosis (OR = 3.87 (95% CI: 1.31-11.42), P = .021) were associated with 90-day mortality. CONCLUSIONS: Although rare, invasive fungal infections remain associated with poor outcome in burn patients. Bacterial co-infection and presence of allograft were potentially modifiable factors independently associated with outcome.

IL-7 Restores T Lymphocyte Immunometabolic Failure in Septic Shock Patients through mTOR Activation.

T lymphocyte alterations are central to sepsis pathophysiology, whereas related mechanisms remain poorly understood. We hypothesized that metabolic alterations could play a role in sepsis-induced T lymphocyte dysfunction. Samples from septic shock patients were obtained at day 3 and compared with those from healthy donors. T cell metabolic status was evaluated in the basal condition and after T cell stimulation. We observed that basal metabolic content measured in lymphocytes by nuclear magnetic resonance spectroscopy was altered in septic patients. Basal ATP concentration, oxidative phosphorylation (OXPHOS), and glycolysis pathways in T cells were decreased as well. After stimulation, T lymphocytes from patients failed to induce glycolysis, OXPHOS, ATP production, GLUT1 expression, glucose entry, and proliferation to similar levels as controls. This was associated with significantly altered mTOR, but not Akt or HIF-1α, activation and only minor AMPKα phosphorylation dysfunction. IL-7 treatment improved mTOR activation, GLUT1 expression, and glucose entry in septic patients' T lymphocytes, leading to their enhanced proliferation. mTOR activation was central to this process, because rapamycin systematically inhibited the beneficial effect of recombinant human IL-7. We demonstrate the central role of immunometabolism and, in particular, mTOR alterations in the pathophysiology of sepsis-induced T cell alterations. Our results support the rationale for targeting metabolism in sepsis with recombinant human IL-7 as a treatment option.

TCR activation mimics CD127lowPD-1high phenotype and functional alterations of T lymphocytes from septic shock patients.

BACKGROUND: Sepsis is the leading cause of mortality for critically ill patients worldwide. Patients develop T lymphocyte dysfunctions leading to T-cell exhaustion associated with increased risk of death. As interleukin-7 (IL-7) is currently tested in clinical trials to reverse these dysfunctions, it is important to evaluate the expression of its specific CD127 receptor on the T-cell surface of patients with septic shock. Moreover, the CD127lowPD-1high phenotype has been proposed as a T-cell exhaustion marker in chronic viral infections but has never been evaluated in sepsis. The objective of this study was first to evaluate CD127 and CD127lowPD-1high phenotype in septic shock in parallel with functional T-cell alterations. Second, we aimed to reproduce septic shock-induced T-cell alterations in an ex vivo model. METHODS: CD127 expression was followed at the protein and mRNA levels in patients with septic shock and healthy volunteers. CD127lowPD-1high phenotype was also evaluated in parallel with T-cell functional alterations after ex vivo activation. To reproduce T-cell alterations observed in patients, purified T cells from healthy volunteers were activated ex vivo and their phenotype and function were evaluated. RESULTS: In patients, neither CD127 expression nor its corresponding mRNA transcript level was modified compared with normal values. However, the percentage of CD127lowPD-1high T cells was increased while T cells also presented functional alterations. CD127lowPD-1high T cells co-expressed HLA-DR, an activation marker, suggesting a role for T-cell activation in the development of this phenotype. Indeed, T-cell receptor (TCR) activation of normal T lymphocytes ex vivo reproduced the increase of CD127lowPD-1high T cells and functional alterations following a second stimulation, as observed in patients. Finally, in this model, as observed in patients, IL-7 could improve T-cell proliferation. CONCLUSIONS: The proportion of CD127lowPD-1high T cells in patients was increased compared with healthy volunteers, although no global CD127 regulation was observed. Our results suggest that TCR activation participates in the occurrence of this T-cell population and in the development of T-cell alterations in septic shock. Furthermore, we provide an ex vivo model for the investigation of the pathophysiology of sepsis-induced T-cell immunosuppression and the testing of innovative immunostimulant treatments.

Clinical use of [TIMP-2]•[IGFBP7] biomarker testing to assess risk of acute kidney injury in critical care: guidance from an expert panel.

BACKGROUND: The first FDA-approved test to assess risk for acute kidney injury (AKI), [TIMP-2]•[IGFBP7], is clinically available in many parts of the world, including the USA and Europe. We sought to understand how the test is currently being used clinically. METHODS: We invited a group of experts knowledgeable on the utility of this test for kidney injury to a panel discussion regarding the appropriate use of the test. Specifically, we wanted to identify which patients would be appropriate for testing, how the results are interpreted, and what actions would be taken based on the results of the test. We used a modified Delphi method to prioritize specific populations for testing and actions based on biomarker test results. No attempt was made to evaluate the evidence in support of various actions however. RESULTS: Our results indicate that clinical experts have developed similar practice patterns for use of the [TIMP-2]•[IGFBP7] test in Europe and North America. Patients undergoing major surgery (both cardiac and non-cardiac), those who were hemodynamically unstable, or those with sepsis appear to be priority patient populations for testing kidney stress. It was agreed that, in patients who tested positive, management of potentially nephrotoxic drugs and fluids would be a priority. Patients who tested negative may be candidates for "fast-track" protocols. CONCLUSION: In the experience of our expert panel, biomarker testing has been a priority after major surgery, hemodynamic instability, or sepsis. Our panel members reported that a positive test prompts management of nephrotoxic drugs as well as fluids, while patients with negative results are considered to be excellent candidates for "fast-track" protocols.

Association between hydroxocobalamin administration and acute kidney injury after smoke inhalation: a multicenter retrospective study.

BACKGROUND: The use of hydroxocobalamin has long been advocated for treating suspected cyanide poisoning after smoke inhalation. Intravenous hydroxocobalamin has however been shown to cause oxalate nephropathy in a single-center study. The impact of hydroxocobalamin on the risk of acute kidney injury (AKI) and survival after smoke inhalation in a multicenter setting remains unexplored. METHODS: We conducted a multicenter retrospective study in 21 intensive care units (ICUs) in France. We included patients admitted to an ICU for smoke inhalation between January 2011 and December 2017. We excluded patients discharged at home alive within 24 h of admission. We assessed the risk of AKI (primary endpoint), severe AKI, major adverse kidney (MAKE) events, and survival (secondary endpoints) after administration of hydroxocobalamin using logistic regression models. RESULTS: Among 854 patients screened, 739 patients were included. Three hundred six and 386 (55.2%) patients received hydroxocobalamin. Mortality in ICU was 32.9% (n = 243). Two hundred eighty-eight (39%) patients developed AKI, including 186 (25.2%) who developed severe AKI during the first week. Patients who received hydroxocobalamin were more severe and had higher mortality (38.1% vs 27.2%, p = 0.0022). The adjusted odds ratio (95% confidence interval) of AKI after intravenous hydroxocobalamin was 1.597 (1.055, 2.419) and 1.772 (1.137, 2.762) for severe AKI; intravenous hydroxocobalamin was not associated with survival or MAKE with an adjusted odds ratio (95% confidence interval) of 1.114 (0.691, 1.797) and 0.784 (0.456, 1.349) respectively. CONCLUSION: Hydroxocobalamin was associated with an increased risk of AKI and severe AKI but was not associated with survival after smoke inhalation. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03558646.