Time course of pro- and anti-inflammatory cytokine levels in patients with burns—Prognostic value of interleukin-10

Aberrant inflammatory responses in intoxicated burn-injured patients parallel impaired cognitive function

Burn-injured patients with alcohol use disorder (AUD) have increased morbidity and mortality compared to alcohol-abstaining individuals with similar injuries. It is hypothesized that this is due, in part, to alcohol-induced dysregulation of the systemic inflammatory response, leading to worsened clinical outcomes, including increased susceptibility to infection, and heightened cognitive impairment. To examine the effects of alcohol on inflammatory markers after burn injury, we used multiplex assays to measure a panel of 48 cytokines, chemokines, and growth factors in the plasma of burn patents within 24 h of admission to the University of Colorado Burn Center. Thirty patients were enrolled between July 2018 to February 2020 and were stratified based on presence of AUD and total body surface area (TBSA) burn of ≥20% into four groups: [AUD-, TBSA <20%, N = 12], [AUD+, TBSA <20%, N = 3], [AUD-, TBSA ≥20%, N = 8], [AUD+, TBSA ≥20%, N = 7]. In addition, Confusion Assessment Method (CAM) scores were collected to evaluate patient delirium during the course of hospitalization. Multivariate statistical analysis demonstrated a number of cytokines and other factors that were significantly different between the groups. For example, the anti-inflammatory cytokine interleukin 1 receptor antagonist (IL-1ra) was dampened in the AUD+, TBSA ≥20% cohort with a 75.2% decrease compared to AUD-, TBSA ≥20%, and an 83.9% decrease compared to AUD-, TBSA <20% (p = 0.008). Additionally, plasma levels of the pro-inflammatory mediator CXCL12 (C-X-C motif chemokine ligand 12, also known as stromal cell-derived factor 1, SDF-1) was higher in the AUD + groups (p = 0.03) and similarly, IL-18 levels were greater in AUD+, TBSA ≥20% (p = 0.009). Eotaxin (also known as cytokine CC motif ligand 11, CCL11) was markedly elevated in the AUD+, TBSA ≥20% cohort with a 2.4-fold increase over the AUD-, TBSA ≥20%, and a 1.7-fold rise compared to the AUD-, TBSA <20% cohorts (p = 0.04). Interestingly, there was also a marked rise in CAM + delirium scores (85.7%) among the AUD + patients with TBSA ≥20% (p = 0.02). Not surprisingly, we found that hospital stays increased with AUD+ and larger burns (p = 0.0009). Our findings reveal that burn patients who misuse alcohol have aberrant inflammatory responses that may lead to greater immune dysregulation and worse clinical outcomes.

VARIABLES INFLUENCING THE DIFFERENTIAL HOST RESPONSE TO BURNS IN PEDIATRIC AND ADULT PATIENTS

ABSTRACT

Burn injury is a significant source of morbidity and mortality in the pediatric population. Although 40,000 pediatric patients in the United States are admitted to the hospital with burn wounds annually, significant differences exist in the management and treatment of these patients, even among highly specialized burn centers. Some aspects of pediatric burn research, such as metabolic changes and nutritional support after burn injury, have been studied extensively; however, in many aspects of burn care, pediatric research lags behind the study of adult populations. This review compares and contrasts a wide array of physiologic and immune responses between children and adults after burn injury. Such a review elucidates where robust research has been conducted, where adult research is applicable to pediatric patients, and where additional pediatric burn research needs to be conducted.

The Complexity of the Post-Burn Immune Response: An Overview of the Associated Local and Systemic Complications

Burn injury induces a complex inflammatory response, both locally and systemically, and is not yet completely unravelled and understood. In order to enable the development of accurate treatment options, it is of paramount importance to fully understand post-burn immunology. Research in the last decades describes insights into the prolonged and excessive inflammatory response that could exist after both severe and milder burn trauma and that this response differs from that of none-burn acute trauma. Persistent activity of complement, acute phase proteins and pro- and anti-inflammatory mediators, changes in lymphocyte activity, activation of the stress response and infiltration of immune cells have all been related to post-burn local and systemic pathology. This "narrative" review explores the current state of knowledge, focusing on both the local and systemic immunology post-burn, and further questions how it is linked to the clinical outcome. Moreover, it illustrates the complexity of post-burn immunology and the existing gaps in knowledge on underlying mechanisms of burn pathology.

EVALUATING SEPSIS CRITERIA IN DETECTING ALTERATIONS IN CLINICAL, METABOLIC, AND INFLAMMATORY PARAMETERS IN BURN PATIENTS

ABSTRACT

Sepsis has become the leading cause of death in burn patients. Furthermore, sepsis and septic complications result in significant morbidities and longer hospitalization, which has profound impacts on the healthcare system. Despite this, sepsis in burn patients is surprisingly poorly understood and characterized. This retrospective, single-institution cohort study aimed to increase our understanding of the septic response after burns. We hypothesized that different sepsis definitions will results in distinctive septic trajectories and biochemical patterns after injury. Sepsis was defined by our burn center-specific prospective definition, the American Burn Association criteria, Sepsis-3 criteria, and the Mann-Salinas criteria. Applying these definitions, we compared clinical, metabolic, and inflammatory markers in septic and nonseptic burn patients. We found that the Sepsis-3 criteria are the most reliable screening tool used before clinical diagnoses for detecting sepsis trajectories and biochemical patterns. Moreover, we characterized distinct temporal alterations in biomarkers during the pre- and post-septic periods in burn patients, which may be incorporated into future sepsis definitions to improve the accuracy of a sepsis diagnosis in burn patients.

Association of the Circulating Supar Levels with Inflammation, Fibrinolysis, and Outcome in Severe Burn Patients

BACKGROUND

Hyperfibrinolysis and pro/anti-inflammatory imbalance usually occur in the early stage of severe burns. Soluble urokinase-type plasminogen activator receptor (suPAR) is involved in fibrinolysis and inflammation. To date, the levels of circulating suPAR in non-survivors with severe burns remain unknown. This study aimed to investigate the early association between circulating suPAR levels and biomarkers of fibrinolysis, pro/anti-inflammatory, and prognosis.

METHODS

Sixty-four consecutive Chinese patients with severe burns and 26 healthy volunteers were enrolled in a prospective observational cohort. Clinical characteristics and laboratory data were collected prospectively. Blood samples were collected at 48 h post-burn, and suPAR and biomarkers of pro/anti-inflammatory and fibrinolysis were detected by enzyme-linked immunosorbent assays. Important indicators between non-survivors and survivors were compared. Linear regression analysis was performed to screen variables associated with suPAR. Logistic regression analysis and receiver operating characteristic curve (ROC) analysis were performed to evaluate the prognostic value of suPAR.

RESULT

Compared with the control group, the circulating suPAR levels in the survivors (P < 0.001) and non-survivors (P = 0.017) were higher. Compared with survivors, non-survivors had lower circulating suPAR levels at 48 h post-burn, and they showed a higher degree of fibrinolysis (higher D-dimer) and a lower TNF-α/IL-10 ratio. According to linear regression analysis, the variables independently associated with a lower suPAR level were lower platelet factor 4 (PF-4), urokinase-type plasminogen activator (uPA), and TNF-α/IL-10 levels and a higher D-dimer level. Logistic regression and ROC analyses indicated that a suPAR level ≤ 4.70 μg/L was independently associated with 30-day mortality.

CONCLUSION

Low circulating suPAR levels at 48 h post-burn in severe burn patients may reflect decreased TNF-α/IL-10 ratio and increased hyperfibrinolysis. suPAR can predict 30-day mortality in patients with severe burn.

The TNF-α (-238 G/A) polymorphism could protect against development of severe sepsis

Primary responses in sepsis-mediated inflammation are regulated by pro-inflammatory cytokines. Variations in the cytokine genes might modify their transcription or expression, plasma cytokines levels and response to sepsis. Activation protein-1 (AP-1) and NF-κB regulate cytokines gene expression in sepsis. A total of 90 severely septic and 91 non-infected patients were prospectively studied. IL-1α (–889 C/T), IL-1β (+3954 C/T), IL-6 (–174 G/C), TNF-α (–238 G/A), TNF-α (–308G/A), IL-8 (–251A/T) and IL-10 (–1082 G/A) SNPs, plasma IL-1β, IL-4, IL-6, IL-8, IL-10, IL-13, IFN-γ, TNF-α and monocyte chemoattractant protein 1 (MCP-1) levels, and AP-1 and NF-κB gene expression by neutrophils were assessed. A allele carriers of TNF-α (–238 G/A) SNP were less frequent among septic patients. IL-6, IL-8, IL-10, TNF-α and MCP-1 levels were higher, and AP-1 and NF-κB gene expressions lower in septic patients. Sepsis was independently associated with higher fibrinogen, neutrophils counts and IL-8 levels, lower prothrombin, absence of the variant A allele of the TNF-α (–238 G/A) SNP, and haemodynamic failure. Death was independently associated with a higher APACHE II score, higher IL-8 levels, and the diagnosis of sepsis. TNF-a (–238 G/A) SNP could protect against sepsis development. Higher IL-8 levels are predictive of sepsis and mortality.

Determination of Serum Levels of Interleukin-6, Interleukin-8, Interleukin-10, and Tumor Necrosis-Alpha and their Relationship With The Total Body Surface Area in Children

There are few studies on the inflammatory processes and the role of cytokines involved in pediatric burn injuries. The present study aims to measure the serum levels of cytokines and their relationship with the degree of burn injury in children. Within the 48 hours of hospitalization, the serum samples were obtained to measure inflammatory cytokines (interleukin-6, interleukin-8, interleukin-10 [IL-6, IL-8, and IL-10] and tumor necrosis factor-alpha [TNF-α]). The level of all of these cytokine factors was assessed by enzyme-linked immunosorbent assay technique. The mean levels of IL-6, IL-8, IL-10, and TNF-α was 18.15 ± 4.77 pg/ml, 59.54 ± 4.59 pg/ml, 8.41 ± 2.09 pg/ml, and 1.48 ± 0.15 pg/ml, respectively, which were higher than the normal range designated for the healthy pediatrics age group. The levels of TNF-α were higher in patients with sepsis (P = .03) and deceased patients (P = .001). There was a statistically significant difference in the levels of IL-8 in patients with second- (.001) and third-degree (.001) burn injuries in comparison to the first-degree burn injuries, and the level of IL-8 was statistically significantly higher in patients with electrical burn injuries in comparison to scald burn injuries (.01). IL-10 was statistically significantly higher in patients with contact burn injuries in comparison to scald (.001) and flame (.03) burn injuries. Cytokine levels in pediatric burn patients increased after severe burn injuries. There was a significant correlation between the levels of IL-8 and the degree of burn injuries.

Early protein C activation is reflective of burn injury severity and plays a critical role in inflammatory burden and patient outcomes

BACKGROUND

Navigating the complexities of a severe burn injury is a challenging endeavour where the natural course of some patients can be difficult to predict. Straddling both the coagulation and inflammatory cascades that feature strongly in the burns systemic pathophysiology, we propose the pleiotropic protein C (PC) system may produce a viable biomarker to assist traditional evaluation methods for diagnostic and prognostic purposes.

METHODS

We enrolled 86 patients in a prospective observational cohort study. Over three weeks, serial blood samples were taken and measured for PC, activated (A)PC, their receptor endothelial protein C receptor (EPCR), and a panel of inflammatory cytokines including C-reactive protein (CRP), tumour necrosis factor-α, interleukin (IL)-1β, IL-6, IL-8, and IL-17. Their temporal trends were analysed alongside clinical factors including burn size, burn depth, presence of inhalational injury, and a composite outcome of requiring increased support.

RESULTS

(i) APC increased from a nadir on Day 3 (2.3±2.1ng/mL vs 4.1±2.5ng/mL by Day 18, p<0.0005), only becoming appropriately correlated to PC from Day 6 onwards (r=0.412-0.721, p<0.05 for all Days 6-21). (ii) This early disturbance in the PC system was amplified in the more severe burns (≥30% total body surface area, predominantly full thickness, or with inhalational injury), which were characterised by a marked fall in PC activation (approximated by APC/PC ratio) and APC levels during Days 0-3 with low unchanged PC levels. Critically low levels of this cytoprotective agent was associated with greater inflammatory burden, as reflected by significantly elevated CRP, IL-6, and IL-8 levels in the more severe compared to less severe burns, and by negative correlations between both PC and APC with most inflammatory cytokines. (iii) Alongside clinical markers of severity at admission (burn size, burn depth, and presence of inhalational injury), only Day 0 APC/PC ratio (OR 1.048 (1.014-1.083), p=0.006), APC (OR 1.364 (1.032-1.803), p=0.029), PC (OR 0.899 (0.849-0.953), p<0.0005), and not any inflammatory cytokines were predictive markers of requiring increased support. Uniquely, decreased Day 0 PC was further individually associated with each increased total length of stay, ICU length of stay, intravenous fluid resuscitation, and total surgeries, as well as possibly mortality.

CONCLUSION

An early functional depletion of the cytoprotective PC system provides a physiological link between severe burns and the cytokine storm, likely contributing to worse outcomes. Our findings on the changes in APC, PC and PC activation during this pathological state support APC and PC as early diagnostic and prognostic biomarkers, and provides a basis for their therapeutic potential in severe burn injuries.

Lack of early platelet and leukocyte activation can indicate complications after major burn injury

BACKGROUND

Major burn injury causes massive tissue destruction consequently enhanced platelet function and leukocyte-mediated inflammatory response.

METHODS

In a prospective, observational study 23 consecutive patients with more than 20% body surface burn injury were followed for five days (T1-T5) after admission to a university intensive care (ICU). Platelet and leukocyte antisedimentation rate (PAR and LAR) was measured by one-hour gravity sedimentation. It detects the percentage of total platelet and leukocyte number crossed the half line of blood sample column, therefore, they can be regarded as cells of decreased specific gravity. We aimed to investigate the time course of PAR and LAR after burn injury, as the trend of platelet and the leukocyte activation in the early post-burn period.

RESULTS

Daily mean PAR and LAR values continuously increased in the observation period (T1 to T5). Daily mean PAR and LAR were lower in ICU non-survivors (n = 7) compared to survivors (n = 16) between T2 and T4 (p < 0.05 and p < 0.01). PAR values of septic patients (n = 10) were lower than that of non-septic ones (n = 13, p < 0.01 at T5).

CONCLUSIONS

Both PAR and LAR, as novel bedside test can predict septic complications and unfavorable outcome after major burn injury. Further studies with higher sample size are warranted.

The pathogenesis and diagnosis of sepsis post burn injury

Burn is an under-appreciated trauma that is associated with unacceptably high morbidity and mortality. Although the survival rate after devastating burn injuries has continued to increase in previous decades due to medical advances in burn wound care, nutritional and fluid resuscitation and improved infection control practices, there are still large numbers of patients at a high risk of death. One of the most common complications of burn is sepsis, which is defined as “severe organ dysfunction attributed to host's disordered response to infection” and is the primary cause of death in burn patients. Indeed, burn injuries are accompanied by a series of events that lead to sepsis and multiple organ dysfunction syndrome, such as a hypovolaemic state, immune and inflammatory responses and metabolic changes. Therefore, clear diagnostic criteria and predictive biomarkers are especially important in the prevention and treatment of sepsis and septic shock. In this review, we focus on the pathogenesis of burn wound infection and the post-burn events leading to sepsis. Moreover, the clinical and promising biomarkers of burn sepsis will also be summarized.

Serum albumin concentration on admission as a predictor of morbidity and mortality in patients with burn injuries

Efforts have been made to determine new predictors of morbidity and mortality in patients with severe burn injuries. This prospective cohort study aimed to determine the association of serum albumin concentration on admission and renal failure, pulmonary infection, sepsis, and death in patients with burn injuries. We included 141 patients, aged >18 years, who were admitted to our institution between April and August 2018. Among them, 59.1% were male and 83.8% had burns covering <20% of the body surface area. Scalds were the most common cause of burns (34.8%). Twelve patients died, of whom eight (66.6%) had an Abbreviated Burn Severity Index (ABSI) ≥8. Patients with serum albumin ≤2.2 g/dL had a higher mortality rate than those with >2.2 g/dL (odds ratios [OR]: 18.7; 95% confidence interval [CI]: 4.9-70.8). Serum albumin ≤2.2 g/dL was also significantly associated with pulmonary infection (OR: 13.1, 95%CI: 3.8-45.7), renal failure (OR: 30.2, 95% CI: 7.4-122.3), and sepsis (OR: 16.9, 95% CI: 4.9-58.3). Serum albumin concentration cut-points and ABSIs were determined to be death predictors using areas under the receiver operating characteristic curves (AUCs). The AUCs with albumin or ABSI alone were 0.89 (95% CI: 0.79-0.98) and 0.92 (95% CI: 0.87-0.96), respectively. The AUC including both albumin and ABSI was 0.96 (95% CI: 0.90-0.98), indicating that the combination is a better death predictor than either measure alone. We confirmed that burn patients with a serum albumin concentration ≤2.2 g/dL on admission have substantially increased morbidity and mortality.

A novel human ex vivo skin model to study early local responses to burn injuries

Burn injuries initiate numerous processes such as heat shock response, inflammation and tissue regeneration. Reliable burn models are needed to elucidate the exact sequence of local events to be able to better predict when local inflammation triggers systemic inflammatory processes. In contrast to other ex vivo skin culture approaches, we used fresh abdominal skin explants to introduce contact burn injuries. Histological and ultrastructural analyses confirmed a partial-thickness burn pathology. Gene expression patterns and cytokine production profiles of key mediators of the local inflammation, heat shock response, and tissue regeneration were analyzed for 24 h after burn injury. We found significantly increased expression of factors involved in tissue regeneration and inflammation soon after burn injury. To investigate purely inflammation-mediated reactions we injected lipopolysaccharide into the dermis. In comparison to burn injury, lipopolysaccharide injection initiated an inflammatory response while expression patterns of heat shock and tissue regeneration genes were unaffected for the duration of the experiment. This novel ex vivo human skin model is suitable to study the local, early responses to skin injuries such as burns while maintaining an intact overall tissue structure and it gives valuable insights into local mechanisms at the very beginning of the wound healing process after burn injuries.

Burn wound excision within 24 h: A 9-year review

BACKGROUND

Severe burns are accompanied by an acute and prolonged hypermetabolic response typified by elevated levels of proinflammatory cytokines and acute phase proteins. When persistent, this inflammatory response can result in multi-organ dysfunction and death. Regarded as the standard of care, early removal of devitalised tissue and eschar mitigates this hypermetabolic response. Ascertaining the optimal time point for early excision, which remains controversial, has several clinical implications.

METHODS

This retrospective observational study included 836 adult thermal burns patients with total burned surface area ≥20% from all Burns Registry of Australia and New Zealand (BRANZ) Hospital sites, including the Victorian Adult Burns Service (VABS), from July 1 2009 to June 30 2018. Patients were divided into two groups, "early" and "delayed", based on a 24-hour excision cut-off from when the injury occurred. Outcome measurements included mortality, hospital length of stay, intensive care unit length of stay, ventilation requirements and the incidence of positive blood cultures.

RESULTS

Among all patients at BRANZ sites, excision within 24 h was associated with reduced mean length of ICU stay (6.6 ± 8.1 vs. 9.2 ± 10.6 days; p = 0.008) and lower mean mechanical ventilator hourly use (94.9 ± 160.8 vs. 159.2 ± 219.1 h; p = 0.001) in the 20-29% TBSA sub-group. Beyond this, no significant differences were observed in outcome measurements.

CONCLUSIONS

While it is physiologically important to perform early burn wound excision to mitigate the inflammatory response, delaying excision beyond 24 h for surgical planning, possibly up to 72 h after injury, may be a reasonable approach for certain patient groups.

Measures of Systemic Innate Immune Function Predict the Risk of Nosocomial Infection in Pediatric Burn Patients

Critical injury-induced immune suppression has been associated with adverse outcomes. This acquired form of immunosuppression is poorly understood in pediatric burn patients, who have infectious complication rates as high as 71%. Our primary objectives were to determine if thermal injury results in early innate immune dysfunction and is associated with increased risk for nosocomial infections (NI). We performed a prospective, longitudinal immune function observational study at a single pediatric burn center. Whole blood samples from burn patients within the first week of injury were used to assess innate immune function. Nosocomial infections were defined using CDC criteria. Immune parameters were compared between patients who went on to develop NI and those that did not. We enrolled a total of 34 patients with 12 developing a NI. Within the first 3 days of injury, children whom developed NI had significantly lower whole blood ex vivo LPS-induced TNFα production capacity (434 pg/mL vs 960 pg/mL, P = .0015), CD14+ monocyte counts (273 cells/µL vs 508 cells/µL, P = .01), and % HLA-DR expression on CD14+ monocytes (54% vs 92%, P = .02) compared with those that did not develop infection. Plasma cytokine levels did not have a significant difference between the NI and no NI groups. Early innate immune suppression can occur following pediatric thermal injury and appears to be a risk factor for the development of nosocomial infections. Plasma cytokines alone may not be a reliable predictor of the development of NI.

Detection of Infection and Sepsis in Burns

Background: Infection is the most frequent complication after severe burns and has a propensity to progress into sepsis then septic shock and multiple organ dysfunction syndrome (MODS). Improving outcomes in acute burn care depends on early detection of infection to allow prompt interventions. Diagnosis of sepsis in severe burns is uniquely challenging because otherwise-typical clinical signs are masked by the hypermetabolic state and systemic inflammation induced by the burn itself. For this reason, burns have historically been excluded from high-impact studies on the diagnosis and treatment of sepsis. Methods: This article provides a comprehensive three-fold review of current findings and guidelines pertinent to the early detection of infection and sepsis in severe burns. Results: First, evidence-based detection of the most common infections encountered in the burn intensive care unit is reviewed. Second, we analyze the evolution of the diagnostic criteria for sepsis and the evidence regarding their utility in severe burns. Last, we examine the development of biomarkers, from procalcitonin to molecular genomics, for the detection of sepsis. Conclusions: Although gold standard methods of early detection of sepsis in burn patients have yet to be identified, improved understanding and appropriate application of the available diagnostic criteria and assays are paramount to providing effective care of patients with severe burns.

Clinical Importance of a Cytokine Network in Major Burns

Major burns elicit an acute inflammatory response including various inflammatory cytokines. Cytokines play mutual interacting roles in inflammatory diseases. There is little evidence of the clinical significance of the cytokine network in patients with major burns. This study aimed to investigate the clinical significance of the cytokine network in patients with major burn. This prospective observational study comprising 38 patients with major burns (total body surface area (%TBSA) ≥ 20%) and 12 healthy controls was conducted from April 2014 to December 2016. Blood samples were collected from patients at six points: day 1, day 2, days 3-5, 1 week, 2 weeks, and 1 month after the burn injury. Inflammatory cytokines (interferon [IFN]-α, IFN-γ, interleukin [IL]-1β, IL-6, IL-8, IL-12/IL-23p40, IL-17A, monocyte chemotactic protein-1 [MCP-1], TNF-α), and anti-inflammatory cytokines (IL-4, IL-10) were measured. Twenty-eight-day mortality, %TBSA, prognostic burn index (PBI) and Sequential Organ Failure Assessment (SOFA), and Acute Physiology and Chronic Health Evaluation (APACHE) II scores were evaluated. Hierarchical clustering analysis and network visualization showed one cluster and network, respectively. Both were formed by four cytokines including IL-6, IL-8, IL-10, and MCP-1 on days 1 and 2, suggesting the presence of a cytokine network in the early hospital phase. Each cytokine showed significant associations with the SOFA score within 5 days and 1 month after burn injury. Cox regression analysis highlighting days 1 and 2 showed significant correlation of IL-6, IL-8, and IL-10 with 28-day mortality. We showed a cytokine network and its relation with prognosis and injury severity on days 1 and 2 and suggest that this cytokine network may play a role in major burns.

Soluble Suppression Of Tumorigenicity-2 Predicts Hospital Mortality in Burn Patients: An Observational Prospective Cohort Pilot Study

BACKGROUND

The IL33/ST2 pathway has been implicated in the pathogenesis of different inflammatory diseases. Our aim was to analyze whether plasma levels of biomarkers involved in the IL33/ST2 axis might help to predict mortality in burn patients.

METHODS

Single-center prospective observational cohort pilot study performed at the Burns Unit of the Plastic and Reconstructive Surgery Department of the Vall d'Hebron University Hospital (Barcelona). All patients aged ≥18 years old with second or third-degree burns requiring admission to the Burns Unit were considered for inclusion. Blood samples were taken to measure levels of interleukins (IL)6, IL8, IL33, and soluble suppression of tumorigenicity-2 (sST2) within 24 h of admission to the Burns Unit and at day 3. Results are expressed as medians and interquartile ranges or as frequencies and percentages.

RESULTS

Sixty-nine patients (58 [84.1%] male, mean age 52 [35-63] years, total body surface area burned 21% [13%-30%], Abbreviated Burn Severity Index 6 [4-8]) were included. Thirteen (18.8%) finally died in the Burns Unit. Plasma levels of sST2 measured at day 3 after admission demonstrated the best prediction accuracy for survival (area under the receiver-operating curve 0.85 [0.71-0.99]; P < 0.001). The best cutoff point for the area under the receiver-operating curve index was estimated to be 2,561. In the Cox proportional hazards model, after adjusting for potential confounding, a plasma sST2 level ≥2,561 measured at day 3 was significantly associated with mortality (hazard ratio 6.94 [1.73-27.74]; P = 0.006).

CONCLUSIONS

Plasma sST2 at day 3 predicts hospital mortality in burn patients.

Early hypoalbuminemia is associated with 28-day mortality in severely burned patients: A retrospective cohort study

BACKGROUND

Hypoalbuminemia is a frequent condition in the first 24 h after a severe burn injury and is associated with worse outcomes.

METHODOLOGY

We investigated the relation between very early hypoalbuminemia (<6 h after admission) and clinical outcome in a retrospective cohort admitted to our unit for severe burn injuries between 2012 and 2017.

RESULTS

73 severely burned patients were included, with a delay of admission of 3 (2-4) h. In a context of early exogenous supply of albumin, admission and 4H Albuminemia (Alb4 h) were significantly lower in deceased patients (respectively, 34 (29-37) vs 27 (23-30) g/l; p = 0.009 and 27 (24-32) vs 21 (17-27) g/l; p = 0.022) whereas albuminemia ≥6 h were not. The best threshold value of Alb4 h to discriminate 28-day mortality was 23 g/l. Patients with an Alb4 h < 23 g/l had a higher 28-day mortality than patients with an Alb4 h ≥ 23 g/l (42% vs 11%; p = 0.003); adjusted OR = 4.47 (95% CI 1.15-17.36); p = 0.03.

CONCLUSION

In severely burned patients receiving early albumin supply, early hypoalbuminemia is associated with higher mortality whereas later albuminemia (≥6 h) is not. Exploration of whether early albumin infusion (8-12 h post injury) may alter clinical outcome is warranted.

Contributing factors and outcomes of burn-associated cholestasis

BACKGROUND & AIMS

Cholestasis often occurs after burn injuries. However, the prevalence of cholestasis and its effect on outcomes in patients with severe burn injuries are unknown. The aim of this study was to describe the course and the burden of cholestasis in a cohort of severely burned adult patients.

METHODS

We investigated the relationship between burn-associated cholestasis (BAC) and clinical outcomes in a retrospective cohort of patients admitted to our unit for severe burn injuries between 2012 and 2015. BAC was defined as an increased level of serum alkaline phosphatase (ALP) ≥1.5x the upper limit of normal (ULN) with an increased level of gamma-glutamyltransferase (GGT) ≥3x ULN, or as an increased level of total bilirubin ≥2x ULN.

RESULTS

A total of 214 patients were included: 111 (52%) patients developed BAC after a median (IQR) stay of 9 (5-16) days. At 90 days, the mortality rate was 20%, including 34 and 9 patients with and without BAC (p <0.001), respectively, which corresponded to a 2.5-fold higher (95% CI 1.2-5.2, p = 0.012) risk of 90-day mortality for patients with BAC. After being adjusted for severity of illness, patients with BAC, hyperbilirubinemia and without elevated ALP and GGT levels had a hazard ratio of 4.51 (95% CI 1.87-10.87) for 90-day mortality. BAC was associated with the severity of the burn injury, shock and bacteraemia. BAC was present in 38 (51%) patients at discharge, and 7 (18%) patients had secondary sclerosing cholangitis. These patients maintained elevated levels of ALP and GGT that were 5.8x (1.7-15) the ULN and 11x the ULN (4.5-22), respectively, 20 months (3.5-35) after discharge.

CONCLUSION

BAC is prevalent among patients with severe burn injuries and is associated with worse short-term outcomes, especially when total bilirubin levels were increased without elevated ALP and GGT levels. BAC survivors are at risk of developing sclerosing cholangitis.

LAY SUMMARY

Cholestasis is common after burn injuries and is associated with burn severity, sepsis, organ failure and mortality. Patients with hyperbilirubinemia without elevated alkaline phosphatase and gamma-glutamyltransferase levels after the burn injury have a poor prognosis. Patients with burn-associated cholestasis may develop sclerosing cholangitis and secondary biliary cirrhosis.

Increased serum concentrations of soluble ST2 predict mortality after burn injury

Background:

Large burn injuries induce a systemic response in affected patients. Soluble ST2 (sST2) acts as a decoy receptor for interleukin-33 (IL-33) and has immunosuppressive effects. sST2 has been described previously as a prognostic serum marker. Our aim was to evaluate serum concentrations of sST2 and IL-33 after thermal injury and elucidate whether sST2 is associated with mortality in these patients.

Methods:

We included 32 burn patients (total body surface area [TBSA] >10%) admitted to our burn intensive care unit and compared them to eight healthy probands. Serum concentrations of sST2 and IL-33 were measured serially using an enzyme-linked immunosorbent assay (ELISA) technique.

Results:

The mean TBSA was 32.5%±19.6%. Six patients (18.8%) died during the hospital stay. Serum analyses showed significantly increased concentrations of sST2 and reduced concentrations of IL-33 in burn patients compared to healthy controls. In our study cohort, higher serum concentrations of sST2 were a strong independent predictor of mortality.

Conclusions:

Burn injuries cause an increment of sST2 serum concentrations with a concomitant reduction of IL-33. Higher concentrations of sST2 are associated with increased in-hospital mortality in burn patients.

The time-course of the inflammatory response to major burn injury and its relation to organ failure and outcome

Burn injury causes major inflammatory activation and cytokine release, however, the temporal resolution of the acute and sub-acute inflammatory response has not yet been fully delineated. To this end, we have quantified 20 inflammatory mediators in plasma from 44 adult patients 0-21 days after burn injury and related the time course of these mediators to % total body surface area (TBSA) burned, clinical parameters, organ failure and outcome. Of the cytokines analyzed in these patients, interleukin 6 (IL-6), IL-8, IL-10 and monocyte chemoattractant protein 1 (MCP-1) correlated to the size of the injury at 24-48h after burn injury. In our study, the concentration of IL-10 had prognostic value in patients with burn injury both measured at admission and at 24-48h after injury. However, simple demographic data such as age, % burned TBSA, inhalation injury and their combination, the Baux score and modified Baux score, outperform most of the cytokines, with the exception of IL-8 and MCP-1 levels on admission, in predicting death.

Predicting and managing sepsis in burn patients: current perspectives

Modern burn care has led to unprecedented survival rates in burn patients whose injuries were fatal a few decades ago. Along with improved survival, new challenges have emerged in the management of burn patients. Infections top the list of the most common complication after burns, and sepsis is the leading cause of death in both adult and pediatric burn patients. The diagnosis and management of sepsis in burns is complex as a tremendous hypermetabolic response secondary to burn injury can be superimposed on systemic infection, leading to organ dysfunction. The management of a septic burn patient represents a challenging scenario that is commonly encountered by providers caring for burn patients despite preventive efforts. Here, we discuss the current perspectives in the diagnosis and treatment of sepsis and septic shock in burn patients.

An oligodeoxynucleotide with AAAG repeats significantly attenuates burn-induced systemic inflammatory responses via inhibiting interferon regulatory factor 5 pathway

Previously, we showed that an oligodeoxynucleotide with AAAG repeats (AAAG ODN) rescued mice from fatal acute lung injury (ALI) induced by influenza virus and inhibited production of tumor necrosis factor-α (TNF-α) in the injured lungs. However, the underlying mechanisms remain to be elucidated. Upon the bioinformatic analysis revealing that the AAAG ODN is consensus to interferon regulatory factor 5 (IRF5) binding site in the cis-regulatory elements of proinflammatory cytokines, we tried to explore whether the AAAG ODN could attenuate burn injury induced systemic inflammatory responses via inhibiting IRF5 pathway. Using the mouse model with sterile systemic inflammation induced by burn injury, we found that AAAG ODN prolonged the life span of the mice, decreased the expression of IRF5 at injured skin, reduced the production of TNF-α and IL-6 in blood and injured skin, and attenuated the ALI. Furthermore, AAAG ODN could bind IRF5 and inhibit the nuclear translocation of IRF5 in THP-1 cells. The data suggested that the AAAG ODN could act as a cytoplasmic decoy capable of interfering the function of IRF5, and be developed as a drug candidate for the treatment of inflammatory diseases.

Can leukocyte antisedimentation rate (LAR) predict septic complications and critical care survival early in polytrauma and burn victims?

BACKGROUND

In polytrauma and burn injury Systemic Inflammatory Response Syndrome (SIRS) develops. SIRS is presented in many hospitalized patients, including those who never develop infection or sepsis. Both in SIRS and sepsis the leukocyte activation occurs. In acute phase reaction leukocytes' upward flotation i.e. leukocyte antisedimentation rate (LAR) can indicate infectious origin.

OBJECTIVE

To evaluate the predictive power of LAR, serum C-reactive protein (CRP) and procalcitonin (PCT) levels regarding mortality risk and development of septic complications.

METHODS

In a prospective, observational study, 36 patients were followed for 5 days (T1-T5) after admission to a critical care unit immediately with severe polytrauma or burn injury. Eleven patients developed septic complications, their LAR, CRP and PCT levels were analyzed before and after 3 days of sepsis was declared.

RESULTS

Ten patients died due to septic complications. In survivors LAR at T1 (p < 0.001) and T2 (p < 0.001) as well as CRP at T1 (p < 0.05) were significantly higher compared to controls and non survivors. In septic patients LAR (p < 0.05) and CRP (p < 0.05) showed a significant drop one day before sepsis was declared. PCT levels failed to predict this.

CONCLUSIONS

Drop in LAR and CRP levels may be warning signs regarding the onset of septic complications after severe polytrauma and burn injury.

The diagnostic and prognostic value of systems biology research in major traumatic and thermal injury: a review

As secondary complications remain a significant cause of morbidity and mortality amongst hospitalised trauma patients, the need to develop novel approaches by which to identify patients at risk of adverse outcome is becoming increasingly important. Centred on the idea that patients who experience “poor” outcome post trauma elicit a response to injury that is distinct from those who experience “good” outcome, tailored therapeutics is an emerging concept aimed at improving current treatment regimens by promoting patient-specific therapies. Making use of recent advancements in the fields of genomics, proteomics and metabolomics, numerous groups have undertaken a systems-based approach to analysing the acute immune and inflammatory response to major traumatic and thermal injury in an attempt to uncover a single or combination of biomarkers that can identify patients at risk of adverse outcome. Early results are encouraging, with all three approaches capable of discriminating patients with “good” outcome from those who develop nosocomial infections, sepsis and multiple organ failure, with differences apparent in blood samples acquired as early as 2 h post injury. In particular, genomic data is proving to be highly informative, identifying patients at risk of “poor” outcome with a higher degree of sensitivity and specificity than statistical models built upon data obtained from existing anatomical and physiological scoring systems. Here, focussing predominantly upon human-based research, we provide an overview of the findings of studies that have investigated the immune and inflammatory response to major traumatic and thermal injury at the genomic, protein and metabolite level, and consider both the diagnostic and prognostic potential of these approaches.

Lentinan ameliorates burn sepsis by attenuating CD4+ CD25+ Tregs

AIM

The aim of our study was to investigate the effect of lentinan on regulatory T cells (Tregs) in sepsis, especially on the generation of interleukin (IL)-10 via regulation of Erk-FoxO1 signaling.

METHODS

BalB/c mice were randomized into five groups: sham group, the group with burns plus Pseudomonas aeruginosa infection, and the groups with burns plus P. aeruginosa infection administered 40, 100, and 250mg/kg of lentinan. The mice were sacrificed on postburn days 0, 1, 2, 3, and 4, respectively, with eight animals per group at each time point. The peripheral blood CD4⁺ CD25⁺ Tregs and CD4⁺ T cells were isolated using magnetic microbeads. The phenotypes were analyzed by flow cytometry. The cytokine levels were determined with enzyme-linked immunosorbent assay (ELISA). Signal transduction was studied by Western blot, quantitative polymerase chain reaction (qPCR), and luciferase assay.

RESULTS

The IL-10-producing capacity of CD4⁺ CD25⁺ Tregs was significantly enhanced in the group with burns plus P. aeruginosa infection, compared with the sham group. Administration of lentinan significantly decreased IL-10 production and FoxP3 expression of CD4⁺ CD25⁺ Tregs. The proliferative activities of CD4⁺ T cells, however, were restored. Lentinan decreased lipopolysaccharide (LPS)-induced IL-10 production in the Tregs isolated from burned mice. In addition, lentinan attenuated LPS-stimulated Erk-FoxO1 activation.

CONCLUSIONS

Lentinan may improve the outcome of postburn sepsis by suppressing LPS-triggered Erk-FoxO1 activation. Consequently, the hyperfunction of CD4⁺ CD25⁺ Tregs is inhibited, leading to a shift in the inflammatory status from Th2 to Th1 in postburn sepsis.

Elevations in inflammatory cytokines are associated with poor outcomes in mechanically ventilated burn patients

BACKGROUND

The treatment of burn patients who undergo mechanical ventilation is complicated by many factors; patient outcomes and mortality could potentially be improved with predictive biomarkers. Severe burn provokes a systemic inflammatory response characterized by the release of a host of cytokines. Recent studies evaluated the prognostic value of temporal changes in cytokine levels in several patient populations, but few have compared differences in the cytokine profiles of survivors and nonsurvivors following severe burn. We previously compared high-frequency percussive ventilation and low-tidal-volume ventilation and found no difference in mortality or cytokine levels between the two treatments. Since it is unknown whether cytokine levels are predictive of mortality in these patients, we performed a post hoc analysis comparing cytokine levels in survivors and nonsurvivors.

METHODS

We evaluated plasma levels of several cytokines (interleukin 1β [IL-1β], IL-6, IL-8, granulocyte-macrophage colony-stimulating factor, and tumor necrosis factor α) for their prognostic biomarker potential related to mortality at 0, 3, and 7 days in survivors and nonsurvivors of burns.

RESULTS

While the majority of values for IL-1β, granulocyte-macrophage colony-stimulating factor, and tumor necrosis factor α fell below the limit of quantification, univariate analysis demonstrated higher plasma levels of IL-6 and IL-8 in nonsurvivors on Day 7. Logistic regression revealed that elevated plasma IL-8 was independently associated with an increased likelihood of the composite end point of death or ventilator-associated pneumonia with odds ratios of 7.9, 26, and 7.3 on Days 0, 3, and 7, respectively.

CONCLUSION

Early increases in plasma IL-8 are associated with a multifold increase in death or ventilator-associated pneumonia in mechanically ventilated burn patients.

LEVEL OF EVIDENCE

Prognostic/epidemiologic study, level IV; therapeutic study, level IV.

Reductions in frontocortical cytokine levels are associated with long-lasting alterations in reward valuation after methamphetamine

Alterations in reward valuation are thought to have a central role at all stages of the addiction process. We previously reported work aversion in an effortful T-maze task following a binge exposure to methamphetamine, and no such changes in effort following escalating doses. Limitations of the T-maze task include its two available options, with an effort requirement, in the form of increasing barrier height, varying incrementally as a function of time, and reward magnitudes held constant. Reward preferences and choices, however, are likely affected by the number of options available and the manner in which alternatives are presented. In the present experiment, we investigated the long-lasting, off-drug effects of methamphetamine on reward choices in a novel effortful maze task with three possible courses of action, each associated with different effort requirements and reward magnitudes. Neuroinflammatory responses associated with drug exposure, proposed as one of the mechanisms contributing to suboptimal choices on effort-based tasks, were also examined. We investigated region-specific changes in pro- and anti-inflammatory markers in the mesocorticolimbic pathway after methamphetamine, and their relationship with animals' reward choices. We observed long-lasting, increased sensitivity to differences in reward magnitude in the methamphetamine group: animals were more likely to overcome greater effort costs to obtain larger rewards on our novel effortful maze task. These behavioral changes were strongly predicted by pronounced decreases in frontocortical cytokines, but not amygdalar or striatal markers. The present results provide the first evidence that neuroinflammatory processes are associated with alterations in reward valuation during protracted drug withdrawal.

Association between early airway damage-associated molecular patterns and subsequent bacterial infection in patients with inhalational and burn injury

Bacterial infection is a major cause of morbidity affecting outcome following burn and inhalation injury. While experimental burn and inhalation injury animal models have suggested that mediators of cell damage and inflammation increase the risk of infection, few studies have been done on humans. This is a prospective, observational study of patients admitted to the North Carolina Jaycee Burn Center at the University of North Carolina who were intubated and on mechanical ventilation for treatment of burn and inhalational injury. Subjects were enrolled over a 2-yr period and followed till discharge or death. Serial bronchial washings from clinically indicated bronchoscopies were collected and analyzed for markers of tissue injury and inflammation. These include damage-associated molecular patterns (DAMPs) such as hyaluronic acid (HA), double-stranded DNA (dsDNA), heat-shock protein 70 (HSP-70), and high-mobility group protein B-1 (HMGB-1). The study population was comprised of 72 patients who had bacterial cultures obtained for clinical indications. Elevated HA, dsDNA, and IL-10 levels in bronchial washings obtained early (the first 72 h after injury) were significantly associated with positive bacterial respiratory cultures obtained during the first 14 days postinjury. Independent of initial inhalation injury severity and extent of surface burn, elevated levels of HA dsDNA and IL-10 in the central airways obtained early after injury are associated with subsequent positive bacterial respiratory cultures in patients intubated after acute burn/inhalation injury.

Inflammatory cytokines and their prognostic ability in cases of major burn injury

Background

Major burn injuries induce inflammatory responses and changes in the levels of various cytokines. This study was conducted to assess early changes in the serum levels of inflammatory cytokines after burn injury, identify cytokines associated with mortality, and characterize correlations among cytokines.

Methods

Blood samples of 67 burn patients were collected on days 1 and 3 after burn injury, and the concentrations of 27 cytokines were measured using the Bio-Plex Suspension Array System (Bio-Rad Laboratories, USA). Blood samples of 25 healthy subjects were used as controls. We analyzed statistical differences in the concentrations of each cytokine between the control and patient groups, between day 1 and day 3, and between survival and nonsurvival groups. Correlations among 27 cytokines were analyzed.

Results

Median concentrations of granulocyte colony-stimulating factor (G-CSF), granulocyte macrophage colony-stimulating factor (GM-CSF), interleukin 1 receptor antagonist (IL-1RA), interleukin 6 (IL-6), interleukin 8 (IL-8), interleukin 10 (IL-10), interleukin 15 (IL-15), monocyte chemoattractant protein-1 (MCP-1), macrophage inflammatory protein 1β (MIP-1β), and vascular endothelial growth factor (VEGF) were significantly higher in burn patients than in controls. IL-1RA, IL-6, and MCP-1 levels were significantly higher in the nonsurvival group than in the survival group on day 1 after burn injury. Correlation analysis of 27 cytokines showed different relationships with one another. Stronger correlations among interferon γ (IFN-γ), IL-2, IL-4, IL-7, IL-12p70, and IL-17 were found.

Conclusions

IL-1RA, IL-6, and MCP-1 may be used as prognostic indicators of mortality in burn patients and the increase in cytokine concentrations is induced by interactions within a complex network of cytokine-related pathways.

Leptin fails to blunt the lipopolysaccharide-induced activation of the hypothalamic-pituitary-adrenal axis in rats

Obesity is a risk factor for sepsis morbidity and mortality, whereas the hypothalamic-pituitary-adrenal (HPA) axis plays a protective role in the body's defence against sepsis. Sepsis induces a profound systemic immune response and cytokines serve as excellent markers for sepsis as they act as mediators of the immune response. Evidence suggests that the adipokine leptin may play a pathogenic role in sepsis. Mouse endotoxaemic models present with elevated leptin levels and exogenously added leptin increased mortality whereas human septic patients have elevated circulating levels of the soluble leptin receptor (Ob-Re). Evidence suggests that leptin can inhibit the regulation of the HPA axis. Thus, leptin may suppress the HPA axis, impairing its protective role in sepsis. We hypothesised that leptin would attenuate the HPA axis response to sepsis. We investigated the direct effects of an i.p. injection of 2 mg/kg leptin on the HPA axis response to intraperitoneally injected 25 μg/kg lipopolysaccharide (LPS) in the male Wistar rat. We found that LPS potently activated the HPA axis, as shown by significantly increased plasma stress hormones, ACTH and corticosterone, and increased plasma interleukin 1β (IL1β) levels, 2 h after administration. Pre-treatment with leptin, 2 h before LPS administration, did not influence the HPA axis response to LPS. In turn, LPS did not affect plasma leptin levels. Our findings suggest that leptin does not influence HPA function or IL1β secretion in a rat model of LPS-induced sepsis, and thus that leptin is unlikely to be involved in the acute-phase endocrine response to bacterial infection in rats.

Flagellin treatment prevents increased susceptibility to systemic bacterial infection after injury by inhibiting anti-inflammatory IL-10+ IL-12- neutrophil polarization

Severe trauma renders patients susceptible to infection. In sepsis, defective bacterial clearance has been linked to specific deviations in the innate immune response. We hypothesized that innate immune modulations observed during sepsis also contribute to increased bacterial susceptibility after severe trauma. A well-established murine model of burn injury, used to replicate infection following trauma, showed that wound inoculation with P. aeruginosa quickly spreads systemically. The systemic IL-10/IL-12 axis was skewed after burn injury with infection as indicated by a significant elevation in serum IL-10 and polarization of neutrophils into an anti-inflammatory ("N2"; IL-10(+) IL-12(-)) phenotype. Infection with an attenuated P. aeruginosa strain (ΔCyaB) was cleared better than the wildtype strain and was associated with an increased pro-inflammatory neutrophil ("N1"; IL-10(-)IL-12(+)) response in burn mice. This suggests that neutrophil polarization influences bacterial clearance after burn injury. Administration of a TLR5 agonist, flagellin, after burn injury restored the neutrophil response towards a N1 phenotype resulting in an increased clearance of wildtype P. aeruginosa after wound inoculation. This study details specific alterations in innate cell populations after burn injury that contribute to increased susceptibility to bacterial infection. In addition, for the first time, it identifies neutrophil polarization as a therapeutic target for the reversal of bacterial susceptibility after injury.

Examination of local and systemic in vivo responses to electrical injury using an electrical burn delivery system

Electrical injuries are devastating and are difficult to manage due to the complexity of the tissue damage and physiological impacts. A paucity of literature exists which describes models for electrical injury. To date, those models have been used primarily to demonstrate thermal and morphological effects at the points of contact. Creating a more representative model for human injury and further elucidating the physics and pathophysiology of this unique form of tissue injury could be helpful in designing stage-appropriate therapy and improving limb salvage. An electrical burn delivery system was developed to accurately and reliably deliver electrical current at varying exposure times. A series of Sprague-Dawley rats were anesthetized and subjected to injury with 1000 V of direct current at incremental exposure times (2-20 seconds). Whole blood and plasma were obtained immediately before shock, immediately postinjury, and then hourly for 3 hours. Laser Doppler images of tissue adjacent to the entrance and exit wounds were obtained at the outlined time points to provide information on tissue perfusion. The electrical exposure was nonlethal in all animals. The size and the depth of contact injury increased in proportion to the exposure times and were reproducible. Skin adjacent to injury (both entrance and exit sites) exhibited marked edema within 30 minutes. In adjacent skin of upper extremity wounds, mean perfusion units increased immediately postinjury and then gradually decreased in proportion to the severity of the injuries. In the lower extremity, this phenomenon was only observed for short contact times, while longer contact times had marked malperfusion throughout. In the plasma, interleukin-10 and vascular endothelial growth factor levels were found to be augmented by injury. Systemic transcriptome analysis revealed promising information about signal networks involved in dermatological, connective tissue, and neurological pathophysiological processes. A reliable and reproducible in vivo model has been developed for characterizing the pathophysiology of high-tension electrical injury. Changes in perfusion were observed near and between entrance and exit wounds that appear consistent with injury severity. Further studies are underway to correlate differential mRNA expression with injury severity.

Prognostic scoring systems in burns: a review

Survival after burn has steadily improved over the last few decades. Patient mortality is, however, still the primary outcome measure for burn care. Scoring systems aim to use the most predictive premorbid and injury factors to yield an expected likelihood of death for a given patient. Age, burn surface area and inhalational injury remain the mainstays of burn prognostication, but their relative weighting varies between scoring systems. Biochemical markers may hold the key to predicting outcomes in burns. Alternatively, the incorporation of global scales such as those used in the general intensive care unit may have relevance in burn patients. Outcomes other than mortality are increasingly relevant, especially as mortality after burns continues to improve. The evolution of prognostic scoring in burns is reviewed with specific reference to the more widely regarded measures. Alternative approaches to burn prognostication are reviewed along with evidence for the use of outcomes other than mortality. The purpose and utility of prognostic scoring in general is discussed with relevance to its potential uses in audit, research and at the bedside.

Lack of Th17 cell generation in patients with severe burn injuries

Immunodeficient patients with severe burn injuries are extremely susceptible to infection with Candida albicans. In addition to Th1 cells, IL-17-producing CD4(+) T cells (Th17 cells) have recently been described as an important effector cell in host anti-Candida resistance. In this study, therefore, we tried to induce Th17 cells in cultures of severely burned patient PBMC by stimulation with the C. albicans Ag (CAg). In the results, the biomarkers for Th17 cells (IL-17 production and intracellular expression of IL-17 and retinoic acid receptor-related orphan receptor γt) were not displayed by burn patient PBMC stimulated with CAg, whereas these biomarkers of Th17 cells were detected in cultures of healthy donor PBMC stimulated with CAg. Burn patient sera were shown to be inhibitory on CAg-stimulated Th17 cell generation in healthy donor PBMC cultures; however, Th17 cells were induced by CAg in healthy donor PBMC cultures supplemented with burn patient sera that were previously treated with anti-IL-10 mAb. Also, the biomarkers of Th17 cells were not induced by CAg in healthy donor PBMC cultures supplemented with rIL-10. IL-10 was detected in serum specimens derived from severely burned patients. These results indicate that Th17 cells are not generated in burn patient PBMC cultures supplemented with CAg. IL-10, produced in response to burn injuries, is shown to be inhibitory on Th17 cell generation. The high susceptibility of severely burned patients to C. albicans infection might be influenced if burn-associated IL-10 production is intervened.

IL-10 polymorphism associated with decreased risk for mortality after burn injury

OBJECTIVE

Evaluation of single nucleotide polymorphisms (SNPs) in the interleukin-10 promoter (-592 and -819) on risk for death after burn injury.

METHODS

Association between the IL-10 SNPs and outcome after burn injury was evaluated in a cohort of 265 patients from Parkland Hospital, Dallas, TX with ≥ 15% TBSA burns without non-burn trauma (ISS ≤ 16), traumatic or anoxic brain injury or spinal cord injury, who survived >48 h under an IRB-approved protocol. Clinical data were collected prospectively and genotyping was conducted by TaqMan assay. Whole blood from 31 healthy volunteers was stimulated with LPS (100 ng/mL) to determine the level of IL-10 expression for each allele by enzyme-linked immunosorbent assay (ELISA).

RESULTS

After adjustment for percent total body surface area (TBSA) burned, inhalation injury, age, gender, and race/ethnicity, carriage of ‑592A and/or ‑819T was significantly associated (P = 0.014) with a decreased risk for death (adjusted odds ratio: 0.404; 95% CI: 0.197-0.829). As the candidate SNPs were in complete linkage disequilibrium, it was not possible to distinguish which allele was associated with decreased mortality risk. Age, inhalation injury, and full-thickness burn size were significantly associated with increased risk for death. In the LPS stimulated blood of healthy controls, carriage of the -592A and/or -819T allele demonstrated a trend for decreased levels of IL-10 (P = 0.079).

CONCLUSION

Carriage of the ‑592A and/or ‑819T allele in the IL-10 promoter appears to reduce the risk for death after burn injury.