Adverse outcomes and an immunosuppressed endotype in septic patients with reduced IFN-γ ELISpot.

BACKGROUNDSepsis remains a major clinical challenge for which successful treatment requires greater precision in identifying patients at increased risk of adverse outcomes requiring different therapeutic approaches. Predicting clinical outcomes and immunological endotyping of septic patients generally relies on using blood protein or mRNA biomarkers, or static cell phenotyping. Here, we sought to determine whether functional immune responsiveness would yield improved precision.METHODSAn ex vivo whole-blood enzyme-linked immunosorbent spot (ELISpot) assay for cellular production of interferon γ (IFN-γ) was evaluated in 107 septic and 68 nonseptic patients from 5 academic health centers using blood samples collected on days 1, 4, and 7 following ICU admission.RESULTSCompared with 46 healthy participants, unstimulated and stimulated whole-blood IFN-γ expression was either increased or unchanged, respectively, in septic and nonseptic ICU patients. However, in septic patients who did not survive 180 days, stimulated whole-blood IFN-γ expression was significantly reduced on ICU days 1, 4, and 7 (all P < 0.05), due to both significant reductions in total number of IFN-γ-producing cells and amount of IFN-γ produced per cell (all P < 0.05). Importantly, IFN-γ total expression on days 1 and 4 after admission could discriminate 180-day mortality better than absolute lymphocyte count (ALC), IL-6, and procalcitonin. Septic patients with low IFN-γ expression were older and had lower ALCs and higher soluble PD-L1 and IL-10 concentrations, consistent with an immunosuppressed endotype.CONCLUSIONSA whole-blood IFN-γ ELISpot assay can both identify septic patients at increased risk of late mortality and identify immunosuppressed septic patients.TRIAL REGISTRYN/A.FUNDINGThis prospective, observational, multicenter clinical study was directly supported by National Institute of General Medical Sciences grant R01 GM-139046, including a supplement (R01 GM-139046-03S1) from 2022 to 2024.

Adverse Long-Term Outcomes and an Immune Suppressed Endotype in Sepsis Patients with Reduced Interferon-γELISpot: A Multicenter, Prospective Observational Study.

BACKGROUND: Sepsis remains a major clinical challenge for which successful treatment requires greater precision in identifying patients at increased risk of adverse outcomes requiring different therapeutic approaches. Predicting clinical outcomes and immunological endotyping of septic patients has generally relied on using blood protein or mRNA biomarkers, or static cell phenotyping. Here, we sought to determine whether functional immune responsiveness would yield improved precision. METHODS: An ex vivo whole blood enzyme-linked immunosorbent (ELISpot) assay for cellular production of interferon-γ (IFN-γ) was evaluated in 107 septic and 68 non-septic patients from five academic health centers using blood samples collected on days 1, 4 and 7 following ICU admission. RESULTS: Compared with 46 healthy subjects, unstimulated and stimulated whole blood IFNγ expression were either increased or unchanged, respectively, in septic and nonseptic ICU patients. However, in septic patients who did not survive 180 days, stimulated whole blood IFNγ expression was significantly reduced on ICU days 1, 4 and 7 (all p<0.05), due to both significant reductions in total number of IFNγ producing cells and amount of IFNγ produced per cell (all p<0.05). Importantly, IFNγ total expression on day 1 and 4 after admission could discriminate 180-day mortality better than absolute lymphocyte count (ALC), IL-6 and procalcitonin. Septic patients with low IFNγ expression were older and had lower ALC and higher sPD-L1 and IL-10 concentrations, consistent with an immune suppressed endotype. CONCLUSIONS: A whole blood IFNγ ELISpot assay can both identify septic patients at increased risk of late mortality, and identify immune-suppressed, sepsis patients.

The Epidemiology of Chronic Critical Illness After Severe Traumatic Injury at Two Level-One Trauma Centers.

OBJECTIVE: To determine the incidence and risk factors of chronic critical illness after severe blunt trauma. DESIGN: Prospective observational cohort study (NCT01810328). SETTING: Two level-one trauma centers in the United States. PATIENTS: One hundred thirty-five adult blunt trauma patients with hemorrhagic shock who survived beyond 48 hours after injury. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Chronic critical illness was defined as an ICU stay lasting 14 days or more with evidence of persistent organ dysfunction. Three subjects (2%) died within the first 7 days, 107 (79%) exhibited rapid recovery and 25 (19%) progressed to chronic critical illness. Patients who developed chronic critical illness were older (55 vs 44-year-old; p = 0.01), had more severe shock (base deficit, -9.2 vs -5.5; p = 0.005), greater organ failure severity (Denver multiple organ failure score, 3.5 ± 2.4 vs 0.8 ± 1.1; p < 0.0001) and developed more infectious complications (84% vs 35%; p < 0.0001). Chronic critical illness patients were more likely to be discharged to a long-term care setting (56% vs 34%; p = 0.008) than to a rehabilitation facility/home. At 4 months, chronic critical illness patients had higher mortality (16.0% vs 1.9%; p < 0.05), with survivors scoring lower in general health measures (p < 0.005). Multivariate analysis revealed age greater than or equal to 55 years, systolic hypotension less than or equal to 70 mm Hg, transfusion greater than or equal to 5 units packed red blood cells within 24 hours, and Denver multiple organ failure score at 72 hours as independent predictors of chronic critical illness (area under the receiver operating curve, 0.87; 95% CI, 0.75-0.95). CONCLUSIONS: Although early mortality is low after severe trauma, chronic critical illness is a common trajectory in survivors and is associated with poor long-term outcomes. Advancing age, shock severity, and persistent organ dysfunction are predictive of chronic critical illness. Early identification may facilitate targeted interventions to change the trajectory of this morbid phenotype.

Clostridium difficile Infections after Blunt Trauma: A Different Patient Population?

BACKGROUND: The epidemiology of Clostridium difficile-associated infection (CDI) has changed, and it is evident that susceptibility is related not only to exposures and bacterial potency, but host factors as well. Several small studies have suggested that CDI after trauma is associated with a different patient phenotype. The purpose of this study was to examine and describe the epidemiologic factors associated with C. difficile in blunt trauma patients without traumatic brain injury using the Trauma-Related Database as a part of the "Inflammation and Host Response to Injury" (Glue Grant) and the University of Florida Integrated Data Repository. METHODS: Previously recorded baseline characteristics, clinical data, and outcomes were compared between groups (67 C. difficile and 384 uncomplicated, 813 intermediate, and 761 complicated non-C. difficile patients) as defined by the Glue Grant on admission and at days seven and 14. RESULTS: The majority of CDI patients experienced complicated or intermediate clinical courses. The mean ages of all cohorts were less than 65 y and CDI patients were significantly older than uncomplicated patients without CDI. The CDI patients had increased days in the hospital and on the ventilator, as well as significantly higher new injury severity scores (NISS), and a greater percentage of patients with NISS >34 points compared with non-CDI patients. They also had greater Marshall and Denver multiple organ dysfunction scores than non-CDI uncomplicated patients, and greater creatinine, alkaline phosphatase, neutrophil count, lactic acid, and PiO2:FiO2 compared with all non-CDI cohorts on admission. In addition, the CDI patients had higher glucose concentrations and base deficit from uncomplicated patients and greater leukocytosis than complicated patients on admission. Several of these changes persisted to days seven and 14. CONCLUSION: Analysis of severe blunt trauma patients with C. difficile, as compared with non-CDI patients, reveals evidence of increased inflammation, immunosuppression, worse acute kidney injury, higher NISS, greater days in the hospital and on the ventilator, higher organ injury scores, and prolonged clinical courses. This supports reports of an increased prevalence of CDI in a younger population not believed previously to be at risk. This unique population may have specific genomic or inflammation-related risk factors that may play more important roles in disease susceptibility. Prospective analysis may allow early identification of at-risk patients, creation of novel therapeutics, and improved understanding of how and why C. difficile colonization transforms into infection after severe blunt trauma.

Successful implementation of a packed red blood cell and fresh frozen plasma transfusion protocol in the surgical intensive care unit.

BACKGROUND: Blood product transfusions are associated with increased morbidity and mortality. The purpose of this study was to determine if implementation of a restrictive protocol for packed red blood cell (PRBC) and fresh frozen plasma (FFP) transfusion safely reduces blood product utilization and costs in a surgical intensive care unit (SICU). STUDY DESIGN: We performed a retrospective, historical control analysis comparing before (PRE) and after (POST) implementation of a restrictive PRBC/FFP transfusion protocol for SICU patients. Univariate analysis was utilized to compare patient demographics and blood product transfusion totals between the PRE and POST cohorts. Multivariate logistic regression models were developed to determine if implementation of the restrictive transfusion protocol is an independent predictor of adverse outcomes after controlling for age, illness severity, and total blood products received. RESULTS: 829 total patients were included in the analysis (PRE, n=372; POST, n=457). Despite higher mean age (56 vs. 52 years, p=0.01) and APACHE II scores (12.5 vs. 11.2, p=0.006), mean units transfused per patient were lower for both packed red blood cells (0.7 vs. 1.2, p=0.03) and fresh frozen plasma (0.3 vs. 1.2, p=0.007) in the POST compared to the PRE cohort, respectively. There was no difference in inpatient mortality between the PRE and POST cohorts (7.5% vs. 9.2%, p=0.39). There was a decreased risk of urinary tract infections (OR 0.47, 95%CI 0.28-0.80) in the POST cohort after controlling for age, illness severity and amount of blood products transfused. CONCLUSIONS: Implementation of a restrictive transfusion protocol can effectively reduce blood product utilization in critically ill surgical patients with no increase in morbidity or mortality.

Persistent inflammation, immunosuppression, and catabolism syndrome after severe blunt trauma.

BACKGROUND: We recently proffered that a new syndrome persistent inflammation, immunosuppression, and catabolism syndrome (PICS) has replaced late multiple-organ failure as a predominant phenotype of chronic critical illness. Our goal was to validate this by determining whether severely injured trauma patients with complicated outcomes have evidence of PICS at the genomic level. METHODS: We performed a secondary analysis of the Inflammation and Host Response to Injury database of adults with severe blunt trauma. Patients were classified into complicated, intermediate, and uncomplicated clinical trajectories. Existing genomic microarray data were compared between cohorts using Ingenuity Pathways Analysis. Epidemiologic data and outcomes were also analyzed between cohorts on admission, Day 7, and Day 14. RESULTS: Complicated patients were older, were sicker, and required increased ventilator days compared with the intermediate/uncomplicated patients. They also had persistent leukocytosis as well as low lymphocyte and albumin levels compared with uncomplicated patients. Total white blood cell leukocyte analysis in complicated patients showed that overall genome-wide expression patterns and those patterns on Days 7 and 14 were more aberrant from control subjects than were patterns from uncomplicated patients. Complicated patients also had significant down-regulation of adaptive immunity and up-regulation of inflammatory genes on Days 7 and 14 (vs. magnitude in fold change compared with control and in magnitude compared with uncomplicated patients). On Day 7, complicated patients had significant changes in functional pathways involved in the suppression of myeloid cell differentiation, increased inflammation, decreased chemotaxis, and defective innate immunity compared with uncomplicated patients and controls. Subset analysis of monocyte, neutrophil, and T-cells supported these findings. CONCLUSION: Genomic analysis of patients with complicated clinical outcomes exhibit persistent genomic expression changes consistent with defects in the adaptive immune response and increased inflammation. Clinical data showed persistent inflammation, immunosuppression, and protein depletion. Overall, the data support the hypothesis that patients with complicated clinical outcomes are exhibiting PICS. LEVEL OF EVIDENCE: Epidemiologic study, level III.

Microfluidics-based capture of human neutrophils for expression analysis in blood and bronchoalveolar lavage.

Gene expression analysis can be a powerful tool in predicting patient outcomes and identifying patients who may benefit from targeted therapies. However, isolating human blood polymorphonuclear cells (PMNs) for genomic analysis has been challenging. We used a novel microfluidic technique that isolates PMNs by capturing CD66b(+) cells and compared it with dextran-Ficoll gradient isolation. We also used microfluidic isolation techniques for blood and bronchoalveolar lavage (BAL) samples of patients with acute respiratory distress syndrome (ARDS) to evaluate PMN genomic alterations secondary to pulmonary sequestration. PMNs obtained from ex vivo lipopolysaccharide (LPS)-stimulated or -unstimulated whole blood from five healthy volunteers were isolated by either dextran-Ficoll gradient, microfluidics capture, or a combination of the two techniques. Blood and BAL fluid PMNs were also isolated using microfluidics from seven hospitalized patients with ARDS. Gene expression was inferred from extracted RNA using Affymetrix U133 Plus 2.0 GeneChips. All methods of PMN isolation produced similar quantities of high-quality RNA, when adjusted for recovered cell number. Unsupervised analysis and hierarchical clustering indicated that LPS stimulation was the primary factor affecting gene expression patterns among all ex vivo samples. Patterns of gene expression from blood and BAL PMNs differed significantly from each other in the patients with ARDS. Isolation of PMNs by microfluidics can be applied to both blood and BAL specimens from critically ill, hospitalized patients. Unique genomic expression patterns are obtained from the blood and BAL fluid of critically ill patients with ARDS, and these differ significantly from genomic patterns seen after ex vivo LPS stimulation.