Burn-Related Dysregulation of Inflammation and Immunity in Experimental and Clinical Studies

Association of inflammatory biomarkers with overall survival in burn patients: a systematic review and meta-analysis

INTRODUCTION

The inflammatory response to burn injuries can lead to organ dysfunction that ultimately results in increased mortality and morbidity. This meta-analysis was conducted to determine the efficacy of inflammatory biomarkers, including the neutrophil to lymphocyte ratio (NLR), platelet to lymphocyte ratio (PLR), procalcitonin (PCT), and C-reactive protein (CRP) as predictive tools of mortality among burn patients.

MATERIAL AND METHODS

The biomarker levels of survivors and non-survivors were consolidated according to guidelines for Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Three main databases were searched electronically: PubMed, Web of Science, and Scopus, on December 8, 2022. The Newcastle-Ottawa Quality Assessment Scale (NOS) was used to evaluate and score the methodological quality of the included studies. The standard mean difference (SMD) with a 95% confidence interval (CI) was utilized.

RESULTS

Twenty-four studies were included in our systematic review and meta-analysis, (3636 total burn patients), of whom 2878 survived. We found that deceased burn patients had elevated levels of NLR (SMD = 0.60, 95% CI; 0.19-1.00, P < 0.001), CRP (SMD = 0.80, 95% CI; 0.02-1.58, P = 0.04), and PCT (SMD = 0.85, 95% CI; 0.45-1.24, P < 0.001), compared to survivors. However, we found no association between PLR and mortality among burn patients (SMD = 0.00, 95% CI; -0.14-0.15, P < 0.001). In addition, CRP was significantly higher in non-survivors (SMD = 0.80, 95% CI; 0.02-1.58, P =0.04). Similar results were also found about PCT (SMD = 0.85, 95% CI; 0.45-1.24, P < 0.001). When we analyzed the PCT data, collected in the first 24-48 hours, we found similar results; the PCT level was significantly higher in non-survivors in the immediate postinjury-period (SMD = 0.67, 95% CI; 0.31-1.02, P < 0.001). There was no publication bias among studies on the role of NLR in burn (Egger's test P = 0.91). The based cut-off values for NLR (13), CRP (71), and PCT (1.77) yielded sensitivities of 69.2%, 100%, and 93.33%, and specificities of 76%, 72.22%, and 72.22% respectively.

DISCUSSION/CONCLUSIONS

PCT is a marker of sepsis, therefore its elevated level is presumably associated with a higher incidence and severity of sepsis among non-survivors. In addition, NLR and CRP are promising biomarkers for predicting and guiding prevention against burn deaths in clinical settings.

Kinetics of Inflammatory Mediators in the Immune Response to Burn Injury: Systematic Review and Meta-Analysis of Animal Studies

Burns are often accompanied by a dysfunctional immune response, which can lead to systemic inflammation, shock, and excessive scarring. The objective of this study was to provide insight into inflammatory pathways associated with burn-related complications. Because detailed information on the various inflammatory mediators is scattered over individual studies, we systematically reviewed animal experimental data for all reported inflammatory mediators. Meta-analyses of 352 studies revealed a strong increase in cytokines, chemokines, and growth factors, particularly 19 mediators in blood and 12 in burn tissue. Temporal kinetics showed long-lasting surges of proinflammatory cytokines in blood and burn tissue. Significant time-dependent effects were seen for IL-1β, IL-6, TGF-β1, and CCL2. The response of anti-inflammatory mediators was limited. Burn technique had a profound impact on systemic response levels. Large burn size and scalds further increased systemic, but not local inflammation. Animal characteristics greatly affected inflammation, for example, IL-1β, IL-6, and TNF-α levels were highest in young, male rats. Time-dependent effects and dissimilarities in response demonstrate the importance of appropriate study design. Collectively, this review presents a general overview of the burn-induced immune response exposing inflammatory pathways that could be targeted through immunotherapy for burn patients and provides guidance for experimental set-ups to advance burn research.

Diagnostic value of procalcitonin and red blood cell distribution width at admission on the prognosis of patients with severe burns: A retrospective analysis

The plasma procalcitonin (PCT) concentration and red blood cell distribution (RDW) value after severe burns can be used as prognostic indicators, but at present, it is difficult to give consideration to sensitivity and specificity in diagnosing the prognosis of severe burns with a single indicator. This study analysed the diagnostic value of plasma PCT concentration and RDW value at admission on the prognosis of severe burn patients to improve its sensitivity and specificity. A total of 205 patients with severe burns who were treated in the First Affiliated Hospital of Anhui Medical University from November 2017 to November 2022 were retrospectively analysed. The optimal cut-off values of plasma PCT concentration and RDW were analysed and counted through the subject curve (ROC curve). According to the cut-off value, patients were divided into high PCT group and low PCT group, high RDW group and low RDW group. The independent risk factors of severe burns were analysed by single-factor and multiple-factor COX regression. Kaplan-Meier survival was used to analyse the mortality of high PCT group and low PCT group, high RDW group and low RDW group. The area under the curve of plasma PCT concentration and RDW value at admission was 0.761 (95% CI, 0.662-0.860, P < .001), 0.687 (95% CI, 0.554-0.820, P = .003) respectively, and the optimal cut-off values of serum PCT concentration and RDW were 2.775 ng/mL and 14.55% respectively. Cox regression analysis found that age, TBSA, and RDW were independent risk factors for mortality within 90 days after severe burns. Kaplan-Meier survival analysis showed that there was a significant difference in the 90-day mortality rate of severe burns between the PCT ≥ 2.775 ng/mL group and the PCT < 2.775 ng/mL group (log-rank: 24.162; P < .001), with the mortality rate of 36.84% versus 5.49%, respectively. The 90-day mortality rate of severe burns was significantly different between the RDW ≥ 14.55% group and the RDW < 14.55% group (log-rank: 14.404; P < .001), with the mortality rate of 44% versus 12.2% respectively. The plasma PCT concentration and RDW value at admission are both of diagnostic value for the 90-day mortality of severe burns, but the plasma PCT concentration has higher sensitivity and the RDW value has higher specificity. Age, TBSA, and RDW were independent risk factors for severe burns, and then plasma PCT concentration was not independent risk factors.

Predictive value of perioperative peripheral blood cells counts for bacteremia and 90-day mortality in severe burn patients

OBJECTIVE

Burn bacteremia is related to immune barrier damage, but whether the level of circulating immune cells predicts outcomes in severe burns is still not clear. This study aimed to explore the predictive value of perioperative blood cells of the first surgery after burn for bacteremia and 90-day death.

METHODS

Data from severe burn patients treated at the First Affiliated Hospital of Sun Yat-sen University from 2011 to 2020 were retrospectively analyzed. Data on monocytes (M), lymphocytes (L), white blood cell-to-platelet ratio (WPR), neutrophil-to-lymphocyte ratio (NLR) in peripheral blood and changes in temperature (T-37) were collected at one day before(X0), the first day after (X1) and the third day after (X3) the primary surgery.Univariate and multivariate logistic regression were used to identify the independent risk factors of bacteremia and death within 90 days, which were used to establish the risk prediction models (xbac and x90d-m) in severely burned patients. Severe burn cases from two other burn centers were selected to verify the prediction models.

RESULTS

We analyzed 169 severe burn cases in the training dataset, with a 90-day mortality of 21.3% (36/169); 56 (33.1%) patients experienced burn bacteremia. Higher M0, WPR0, NLR0, NLR3, T3-37, ∆M (M0-M3) and lower M3, L3 were associated with higher risk of bacteremia (P < 0.05). Multivariate regression analysis showed that SOFA0, WPR0, M3, and T3-37 were independently associated with bacteremia. The prediction model for bacteremia Xbac = 0.1809 × SOFA0 + 6.532 × WPR0-1.171 × M3 + 0.6987 × T3-37- 2.297. TBSAB, SOFA0, and ∆M (M0-M3) were independently correlated with 90-day mortality. The risk prediction model X90d-m= 0.055 × TBSAB + 0.301 ×SOFA0 + 1.508 × ∆M - 7.196. External validation suggested that the specificity, sensitivity and AUC of the prediction model Xbac was 90.7%, 62.5% and 0.797, respectively; of the prediction model X90d-m was 69.2%, 90.0% and 0.873, respectively.

CONCLUSION

Peripheral M3, WPR0 and ∆M (M0-M3) during the primary surgery has reasonable predictive ability for bacteremia and 90-day mortality in severe burn patients, which could inform clinical antimicrobial judgment and prognostication.

Burn-Induced Local and Systemic Immune Response: Systematic Review and Meta-Analysis of Animal Studies

As burn injuries are often followed by a derailed immune response and excessive inflammation, a thorough understanding of the occurring reactions is key to prevent secondary complications. This systematic review, that includes 247 animal studies, shows the post-burn response of 14 different immune cell types involved in immediate and long-term effects, in both wound tissue and circulation. Peripheral blood neutrophil and monocyte numbers increased directly after burns, whereas thrombocyte numbers increased near the end of the first week. Lymphocyte numbers, however, were decreased for at least two weeks. In burn wound tissue, neutrophil and macrophage numbers accumulated during the first three weeks. Burns also altered cellular functions as we found increased migratory potential of leukocytes, impaired antibacterial activity of neutrophils and enhanced inflammatory mediator production by macrophages. Neutrophil surges were positively associated with burn size and were highest in rats. Altogether, this comprehensive overview of the temporal immune cell dynamics shows that unlike normal wound healing, burn injury induces a long-lasting inflammatory response. It provides a fundamental research basis to improve experimental set-ups, burn care and outcome.

sEH-derived metabolites of linoleic acid drive pathologic inflammation while impairing key innate immune cell function in burn injury

Oxylipins alter immune cell function and potentially drive pathophysiology in burn and sepsis patients. Past and recent data reveal a correlation between increased systemic EpOME levels and reduced survival in human burn trauma and sepsis. This work extends these studies and provides evidence that the downstream sEH-derived metabolites, DiHOMEs, are driving worsening outcomes by altering the immune response. Inhibiting DiHOME metabolite formation with the sEH inhibitor, 1-trifluoromethoxyphenyl-3-(1-propionylpiperidin-4-yl) urea (TPPU), restored immune function by increasing immune cell survival and function. These data support the hypothesis that sEH-derived linoleic acid diols are responsible for increased mortality in burn and sepsis patients and also provide a rationale for testing the therapeutic blockage of DiHOME generation in burn and sepsis patients to improve their outcomes.

Fatty acid composition in the Western diet has shifted from saturated to polyunsaturated fatty acids (PUFAs), and specifically to linoleic acid (LA, 18:2), which has gradually increased in the diet over the past 50 y to become the most abundant dietary fatty acid in human adipose tissue. PUFA-derived oxylipins regulate a variety of biological functions. The cytochrome P450 (CYP450)–formed epoxy fatty acid metabolites of LA (EpOMEs) are hydrolyzed by the soluble epoxide hydrolase enzyme (sEH) to dihydroxyoctadecenoic acids (DiHOMEs). DiHOMEs are considered cardioprotective at low concentrations but at higher levels have been implicated as vascular permeability and cytotoxic agents and are associated with acute respiratory distress syndrome in severe COVID-19 patients. High EpOME levels have also correlated with sepsis-related fatalities; however, those studies failed to monitor DiHOME levels. Considering the overlap of burn pathophysiology with these pathologies, the role of DiHOMEs in the immune response to burn injury was investigated. 12,13-DiHOME was found to facilitate the maturation and activation of stimulated neutrophils, while impeding monocyte and macrophage functionality and cytokine generation. In addition, DiHOME serum concentrations were significantly elevated in burn-injured mice and these increases were ablated by administration of 1-trifluoromethoxyphenyl-3-(1-propionylpiperidin-4-yl) urea (TPPU), a sEH inhibitor. TPPU also reduced necrosis of innate and adaptive immune cells in burned mice, in a dose-dependent manner. The findings suggest DiHOMEs are a key driver of immune cell dysfunction in severe burn injury through hyperinflammatory neutrophilic and impaired monocytic actions, and inhibition of sEH might be a promising therapeutic strategy to mitigate deleterious outcomes in burn patients.

Isosteviol reduces the acute inflammatory response after burns by upregulating MMP9 in macrophages leading to M2 polarization

Isosteviol is a widely known sweetener isolated from the herb Stevia rebaudiana. It is well documented that isosteviol, a derivative of stevioside, has a variety of biological activities, including anti-inflammatory, anti-hypertensive, and cardioprotective effects and alleviation of ischaemia-reperfusion injury. However, the protective mechanism of isosteviol in burn injuryis still unclear. This work aimed to screen and identify the role of macrophage-related genes after burn injury through bioinformatic analysis and biological experiments and to detect the effect of isosteviol on burn inflammation. The results showed that two days after burn injury was considered the acute inflammatory response node, which was when the expression levels of CCL3, CCL4, MMP9, and CD86 in macrophages were significantly changed. Monitoring and regulating these sensitive indicators may help to evaluate the severity of burns and reduce the inflammatory impact of burns on the body. After treatment with isosteviol, during the acute inflammatory phase, the expression of MMP9 was increased, the polarization of macrophages towards the alternatively activated (M2) phenotype was increased, and IL-6 and TNF-α levels were significantly decreased. Our study provides evidence thatisosteviol can reduce inflammation after burn injury by promoting an increase in the M2-classically activated (M1) macrophage ratio and increasing the expression of MMP9 in burn wound tissue during acute inflammation.

Identifying changes in immune cells and constructing prognostic models using immune-related genes in post-burn immunosuppression

BACKGROUND

Burn patients are prone to infection as well as immunosuppression, which is a significant cause of death. Currently, there is a lack of prognostic biomarkers for immunosuppression in burn patients. This study was conducted to identify immune-related genes that are prognosis biomarkers in post-burn immunosuppression and potential targets for immunotherapy.

METHODS

We downloaded the gene expression profiles and clinical data of 213 burn patients and 79 healthy samples from the Gene Expression Omnibus (GEO) database. Immune infiltration analysis was used to identify the proportion of circulating immune cells. Functional enrichment analyses were carried out to identify immune-related genes that were used to build miRNA-mRNA networks to screen key genes. Next, we carried out correlation analysis between immune cells and key genes that were then used to construct logistic regression models in GSE77791 and were validated in GSE19743. Finally, we determined the expression of key genes in burn patients using quantitative reverse transcription polymerase chain reaction (qRT-PCR).

RESULTS

A total of 745 differently expressed genes were screened out: 299 were up-regulated and 446 were down-regulated. The number of Th-cells (CD4+) decreased while neutrophils increased in burn patients. The enrichment analysis showed that down-regulated genes were enriched in the T-cell activation pathway, while up-regulated genes were enriched in neutrophil activation response in burn patients. We screened out key genes (NFATC2, RORA, and CAMK4) that could be regulated by miRNA. The expression of key genes was related to the proportion of Th-cells (CD4+) and survival, and was an excellent predictor of prognosis in burns with an area under the curve (AUC) value of 0.945. Finally, we determined that NFATC2, RORA, and CAMK4 were down-regulated in burn patients.

CONCLUSION

We found that NFATC2, RORA, and CAMK4 were likely prognostic biomarkers in post-burn immunosuppression and potential immunotherapeutic targets to convert Th-cell dysfunction.

Therapeutic Effect of Darkling Beetle (Zophobas morio) Hemolymph on Skin Thermal Injury in Mice Infected by Staphylococcus haemolyticus

Staphylococci are the most common pathogens isolated from skin infections in livestock or companion animals. Antibiotic therapy is the best treatment for infections, but local or systemic use of antimicrobials increases the risk of bacterial resistance. Insects are rich in antimicrobial peptides, which can reduce bacterial resistance and can be used to treat bacterial infections after skin burns. We propose that the use of the darkling beetle (Z. morio) hemolymph to treat skin infections in mice by Staphylococcus haemolyticus is one of the alternatives. Z. morio hemolymph alleviated the increase in wound area temperature in mice with a skin infection, reduced the bacterial load of the wound, and accelerated the wound healing speed significantly. Pathological sections showed that Z. morio hemolymph can significantly reduce inflammatory cell infiltration, and promote skin tissue repair. Real-time fluorescent quantitative polymerase chain reaction (PCR) revealed that the Z. morio hemolymph can significantly reduce the levels of pro-inflammatory cytokines, including interleukin-1 beta (IL-1β), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), and chemokine interleukin-8 (IL-8). Our findings suggest that Z. morio antibacterial hemolymph can promote wound contraction, relieve local inflammatory responses and promote wound healing in mice infected with a heat injury, which has a positive therapeutic effect and enormous potential for skin thermal injury.

Burn-induced heterotopic ossification from incidence to therapy: key signaling pathways underlying ectopic bone formation

Burn injury is one of the potential causes of heterotopic ossification (HO), which is a rare but debilitating condition. The incidence ranges from 3.5 to 5.6 depending on body area. Burns that cover a larger percentage of the total body surface area (TBSA), require skin graft surgeries, or necessitate pulmonary intensive care are well-researched risk factors for HO. Since burns initiate such complex pathophysiological processes with a variety of molecular signal changes, it is essential to focus on HO in the specific context of burn injury to define best practices for its treatment. There are numerous key players in the pathways of burn-induced HO, including neutrophils, monocytes, transforming growth factor-β1-expressing macrophages and the adaptive immune system. The increased inflammation associated with burn injuries is also associated with pathway activation. Neurological and calcium-related contributions are also known. Endothelial-to-mesenchymal transition (EMT) and vascularization are known to play key roles in burn-induced HO, with hypoxia-inducible factor-1 (HIF-1) and vascular endothelial growth factor (VEGF) as potential initiators. Currently, non-steroidal anti-inflammatory drugs (NSAIDs) and radiotherapy are effective prophylaxes for HO. Limited joint motion, ankylosis and intolerable pain caused by burn-induced HO can be effectively tackled via surgery. Effective biomarkers for monitoring burn-induced HO occurrence and bio-prophylactic and bio-therapeutic strategies should be actively developed in the future.

Plasma Neutrophil-to-Lymphocyte Ratio on the Third Day Postburn is Associated with 90-Day Mortality Among Patients with Burns Over 30% of Total Body Surface Area in Two Chinese Burns Centers

INTRODUCTION

Neutrophil-to-lymphocyte ratio (NLR) is a marker of inflammation. This study aimed to evaluate the potential role of NLR to predict 90-day mortality.

METHODS

Data of 577 patients with burns over 30% of total body surface area were collected and retrospectively analyzed. The risk factors for 90-day mortality were evaluated using logistic regression analyses. Receiver operating characteristic (ROC) curve analysis of the 3rd day NLR was performed and the optimal cut-off value was calculated. The 90-day mortality rates were compared between high and low NLR groups using Kaplan-Meier analysis.

RESULTS

Age, mechanical ventilation, burn index, 3rd day NLR, and 7th day red blood cell and platelet (PLT) counts were found to be independent predictive values for 90-day mortality. In contrast, percentage of total body surface area burned, inhalation injury, 1st day white blood cell and neutrophil counts, the 3rd day lymphocytes and PLT counts, and 7th day hemoglobin level were not independently associated with 90-day mortality. The area under the ROC curve of the 3rd day NLR for severe burn-delayed death prediction was 0.665 (95% confidence interval, 0.591-0.739), and the optimal cut-off value of the 3rd day NLR was 10.50. The 90-day mortality rates differed significantly between the NLR >10.5 group and the NLR ≤ 10.5 group (17.03% vs 5.92%, respectively; P < 0.01).

CONCLUSION

These results suggested that the 3rd day NLR was associated with an increased risk of death in severely burned patients; thus, it can provide useful information to predict 90-day mortality.

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.

Bacterial infection profile and predictors among patients admitted to a burn care center: A retrospective study

BACKGROUND

Infection is the main cause of mortality and complications in burn patients. The present study was the first to examine the local profile and antecedents of bacterial infections among patients admitted to a Lebanese burn care center.

METHODS

The present study was a retrospective analysis of the occurrence and recurrence of infection, its characteristics as well as antimicrobial susceptibility among 475 patients admitted to the Burn Centre at the Lebanese Geitaoui Hospital between January 2014 and December 2018.

RESULTS

55% of patients contracted at least one infection during their hospitalization. Length of stay (LOS), sepsis, wound dressing under anesthesia, blood transfusion and female sex independently and positively predicted infection in burn patients. Infection was predominately caused by Staphylococcus aureus (48.7%), followed by Pseudomonas aeruginosa (22.6%) and Acinetobacter baumannii (15.7%). Bacterial isolates were predominately multi-drug or extensively drug resistant and showed variable antimicrobial susceptibility patterns. Recurrent infections occurred in 44.1% of infected burn patients, and were independently predicted by LOS (p = 0.004), sepsis (p = 0.001), surgery (p = 0.003), burn excision and skin grafting (p = 0.019), and central line insertion (p = 0.004).

CONCLUSION

Existing burn management and infection control measures must be revised in order to reduce the incidence and improve the treatment of infections in burn patients.

Delayed application of silver nanoparticles reveals the role of early inflammation in burn wound healing

Burn injury is common, and antimicrobial agents are often applied immediately to prevent wound infection and excessive inflammatory response. Although inflammation is essential for clearing bacteria and creating an environment conducive to the healing process, it is unclear what time-frame inflammation should be present for optimal wound healing. This study critically investigated the role of early inflammation in burn wound healing, and also revealed the molecular mechanisms underlying the pro-healing effects of silver nanoparticles (AgNPs). We created a burn injury mouse model using wild-type and Smad3−/− mice, which were topically treated with AgNPs at different post-burn days, and examined the healing processes of the various groups. We also delineated the molecular pathways underlying the anti-inflammation and pro-healing effects of AgNPs by morphological and histological analysis, immuno-histochemistry, and western blotting. Our results showed that (1) AgNPs regulated pro-inflammatory cytokine IL-6 production of keratinocytes and neutrophils infiltration through KGF-2/p38 signaling pathway, (2) Topical AgNPs treatment immediately after burn injury significantly supressed early inflammation but resulted in delayed healing, (3) A short delay in AgNPs application (post-burn day 3 in our model) allowed early inflammation in a controlled manner, and led to optimal burn wound healing. Thus, our current study showed that some degree of early inflammation was beneficial, but prolonged inflammation was detrimental for burn wound healing. Further evaluation and clinical translation of this finding is warranted.

Imbalance of Circulating Innate Lymphoid Cell Subpopulations in Patients With Septic Shock

Background: Septic shock, a major cause of death in critical care, is the clinical translation of a cytokine storm in response to infection. It can be complicated by sepsis-induced immunosuppression, exemplified by blood lymphopenia, an excess of circulating Treg lymphocytes, and decreased HLA-DR expression on circulating monocytes. Such immunosuppression is associated with secondary infections, and higher mortality. The effect of these biological modifications on circulating innate lymphoid cells (ILCs) has been little studied.

Methods: We prospectively enrolled patients with septic shock (Sepsis-3 definition) in the intensive care unit (ICU) of Timone CHU Hospital. ICU controls (trauma, cardiac arrest, neurological dysfunction) were recruited at the same time (NCT03297203). We performed immunophenotyping of adaptive lymphocytes (CD3⁺ T cells, CD19⁺ B cells, CD4⁺CD25⁺FoxP3⁺ Treg lymphocytes), ILCs (CD3⁻CD56⁺ NK cells and helper ILCs – ILC1, ILC2, and ILC3), and monocytes by flow cytometry on fresh blood samples collected between 24 and 72 h after admission.

Results: We investigated adaptive and innate circulating lymphoid cells in the peripheral blood of 18 patients in septic shock, 15 ICU controls, and 30 healthy subjects. As expected, the peripheral blood lymphocytes of all ICU patients showed lymphopenia, which was not specific to sepsis, whereas those of the healthy volunteers did not. Circulating CD3⁺ T cells and CD3⁻CD56⁺ NK cells were mainly concerned. There was a tendency toward fewer Treg lymphocytes and lower HLA-DR expression on monocytes in ICU patients with sepsis. Although the ILC1 count was higher in septic patients than healthy subjects, ILC2, and ILC3 counts were lower in both ICU groups. However, ILC3s within the total ILCs were overrepresented in patients with septic shock. The depression of immune responses has been correlated with the occurrence of secondary infections. We did not find any differences in ILC distribution according to this criterion.

Conclusion: All ICU patients exhibit lymphopenia, regardless of the nature (septic or sterile) of the initial medical condition. Specific distribution of circulating ILCs, with an excess of ILC1, and a lack of ILC3, may characterize septic shock during the first 3 days of the disease.

Candidemia in major burn patients and its possible risk factors: A 6-year period retrospective study at a burn ICU

OBJECTIVE

The aims of this study were to evaluate the epidemiological and clinical characteristics of candidemia in a typical burn ICU, and to determine the risk factors associated with candidemia among major burn patients.

METHOD

This retrospective observational study of candidemia from 2012 to 2017 in a burn ICU was conducted in the Department of Burn, Southwest hospital, Chongqing, China.

RESULTS

The study included 410 major burn patients (≥40% total body surface area), 39 (9.51%) of which were diagnosed with candidemia. The annual incidences of candidemia varied from 6.06% to 17.54%, and increased gradually in the 6 years. Candida parapsilosis was the dominant pathogen (28.21% strains). The overall resistance rate of Candida spp. to fluconazole was 35.89%. Candidemia cases most frequently occurred in the 2nd (30.77%) and 3rd (23.08%) weeks after burn, and intravascular catheters were the most common sources of bloodstream Candida infections (31.58%). The crude mortality of candidemia was 23.08%, and the mortality attributable to candidemia was 14.99%. Risk factors of candidemia included inhalation injury, renal dysfunction with replacement therapy, severe gastrointestinal complications, T-cell lymphopenia and prior Candida colonization.

CONCLUSION

Candidemia has a high incidence and mortality in major burn patients. The changes in etiology and drug sensitivity may make new challenges for the management of candidemia in burn ICUs.