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

Administration and effects of beta blockers and oxandrolone in severely burned adults: a post hoc analysis of the RE-ENERGIZE trial

Background

Prospective randomized trials in severely burned children have shown the positive effects of oxandrolone (OX), beta blockers (BB) and a combination of the two (BBOX) on hypermetabolism, catabolism and hyperinflammation short- and long-term post-burn. Although data on severely burned adults are lacking in comparison, BB, OX and BBOX appear to be commonly employed in this patient population. In this study, we perform a secondary analysis of an international prospective randomized trial dataset to provide descriptive evidence regarding the current utilization patterns and potential treatment effects of OX, BB and BBOX.

Methods

The RE-ENERGIZE (RandomizEd Trial of ENtERal Glutamine to minimIZE Thermal Injury, NCT00985205) trial included 1200 adult patients with severe burns. We stratified patients according to their receipt of OX, BB, BBOX or none of these drugs (None) during acute hospitalization. Descriptive statistics describe the details of drug therapy and unadjusted analyses identify predisposing factors for drug use per group. Association between OX, BB and BBOX and clinical outcomes such as time to discharge alive and 6-month mortality were modeled using adjusted multivariable Cox regressions.

Results

More than half of all patients in the trial received either OX (n = 138), BB (n = 293) or BBOX (n = 282), as opposed to None (n = 487, 40.6%). Per study site and geographical region, use of OX, BB and BBOX was highly variable. Predisposing factors for the use of OX, BB and BBOX included larger total body surface area (TBSA) burned, higher acute physiology and chronic health evaluation (APACHE) II scores on admission and younger patient age. After adjustment for multiple covariates, the use of OX was associated with a longer time to discharge alive [hazard ratio (HR) 0.62, confidence interval (CI) (0.47-0.82) per 100% increase, p = 0.001]. A higher proportion of days on BB was associated with lower in-hospital-mortality (HR: 0.5, CI 0.28-0.87, p = 0.015) and 6-month mortality (HR: 0.44, CI 0.24-0.82, p = 0.01).

Conclusions

The use of OX, BB and BBOX is common within the adult burn patient population, with its use varying considerably across sites worldwide. Our findings found mixed associations between outcomes and the use of BB and OX in adult burn patients, with lower acute and 6-month-mortality with BB and longer times to discharge with OX. Further research into these pharmacological modulators of the pathophysiological response to severe burn injury is indicated.

ALTERED PROFILES OF EXTRACELLULAR MITOCHONDRIAL DNA IN IMMUNOPARALYZED PEDIATRIC PATIENTS AFTER THERMAL INJURY

ABSTRACT

Background: Thermal injury is a major cause of morbidity and mortality in the pediatric population worldwide with secondary infection being the most common acute complication. Suppression of innate and adaptive immune function is predictive of infection in pediatric burn patients, but little is known about the mechanisms causing these effects. Circulating mitochondrial DNA (mtDNA), which induces a proinflammatory signal, has been described in multiple disease states but has not been studied in pediatric burn injuries. This study examined the quantity of circulating mtDNA and mtDNA mutations in immunocompetent (IC) and immunoparalyzed (IP) pediatric burn patients. Methods: Circulating DNA was isolated from plasma of pediatric burn patients treated at Nationwide Children's Hospital Burn Center at early (1-3 days) and late (4-7 days) time points postinjury. These patients were categorized as IP or IC based on previously established immune function testing and secondary infection. Three mitochondrial genes, D loop, ND1, and ND4, were quantified by multiplexed qPCR to assess both mtDNA quantity and mutation load. Results: At the early time point, there were no differences in plasma mtDNA quantity; however, IC patients had a progressive increase in mtDNA over time when compared with IP patients (change in ND1 copy number over time 3,880 vs. 87 copies/day, P = 0.0004). Conversely, the IP group had an increase in mtDNA mutation burden over time. Conclusion: IC patients experienced a significant increase in circulating mtDNA quantity over time, demonstrating an association between increased mtDNA release and proinflammatory phenotype in the burn patients. IP patients had significant increases in mtDNA mutation load likely representative of degree of oxidative damage. Together, these data provide further insight into the inflammatory and immunological mechanisms after pediatric thermal injury.

Association between incubator standards and newborn nosocomial infection with machine-learning prediction

Background

Newborns have a high incidence of nosocomial infection (NI). We conducted a logistic regression to analyze different incubator standards and other risk factors for newborn NI, which could better help clinical choice of incubator standard.

Methods

Newborns with complete necessary clinical data were included. We collected the demographic and incubator data of 76 patients (40 uninfected and 36 infected) at the Heping Hospital Affiliated to Changzhi Medical College. An analysis of variance, Pearson correlation matrix analysis, and logistic regression analysis were conducted to explore the different incubator standards and other risk factors for neonatal hospital infections. In addition, 4 machine-learning algorithms were used to predict neonatal hospital infections.

Results

We found differences in the gestational age, incubator type, paternal age, and maternal age between the 2 groups. The correlation analysis only revealed a correlation between paternal age and maternal age. The logistic regression showed that gestational age [odds ratio (OR)= 0.77574, 95% confidence interval (CI): 0.583513-0.996354] and the new standard incubator (OR =0.011639, 95% CI: 0.000958-0.067897) may be protective factors for infant infection during hospitalization. Among the extreme gradient boosting (XGBoost), random forest (RF), support vector machine (SVM), and decision tree (DT) algorithms, XGBoost had the best performance in terms of accuracy, sensitivity, specificity, and precision.

Conclusions

We found early gestational age and incubator standards may be risk factors for the NIs of newborns, which might help clinicians to improve the health and safety standards for incubators. XGBoost can be used to predict newborn NIs.

DEMOGRAPHICS TO DEFINE PEDIATRIC BURN PATIENTS AT RISK OF ADVERSE OUTCOMES

ABSTRACT

Background: There is currently no standard definition of a severe burn in the pediatric patient population to identify those at higher risk of infectious complications. Our aim was to correlate total burn surface area (TBSA), burn depth, and type of burn injury to nosocomial infection rates and systemic immune system responses to better define risk factors associated with adverse outcomes. Methods: A prospective observational study at a single-center, quaternary-care, American Burn Association-verified pediatric burn center was conducted from 2016 to 2021. Blood was collected within 72 h of injury from 103 pediatric patients. Whole blood was incubated with lipopolysaccharide or phytohemagglutinin stimulation reagent to measure innate and adaptive immune response, respectively. Flow cytometry was performed on whole blood samples to measure both innate and adaptive immune cells. Unstimulated plasma was also extracted, and IL-6 and IL-10 as well as soluble proteins B- and T-lymphocyte attenuator, CD27, and T-cell immunoglobulin mucin 3 were quantified. Results: There was a significant increased risk for nosocomial infection in pediatric patients with TBSA burns of ≥20%, full-thickness burn injuries ≥5%, or flame burn injuries. There was an overall decrease in both innate and adaptive immune function in patients with TBSA burns ≥20% or full-thickness burn injuries ≥5%. Both burn injury characteristics were also associated with a significant increase in unstimulated IL-6 and IL-10 and soluble immunoregulatory checkpoint proteins. We observed a significant decrease in soluble B- and T-lymphocyte attenuator for those with a flame injury, but there were no other differences between flame injury and scald/contact burns in terms of innate and adaptive immune function. Conclusion: Burns with ≥20% TBSA or ≥5% full thickness in pediatric patients are associated with systemic immune dysfunction and increased risk of nosocomial infections.

Early detection of soluble CD27, BTLA, and TIM-3 predicts the development of nosocomial infection in pediatric burn patients

Thermal injury induces concurrent inflammatory and immune dysfunction, which is associated with adverse clinical outcomes. However, these effects in the pediatric population are less studied and there is no standard method to identify those at risk for developing infections. Our goal was to better understand immune dysfunction and identify soluble protein markers following pediatric thermal injury. Further we wanted to determine which early inflammatory, soluble, or immune function markers are most predictive of the development of nosocomial infections (NI) after burn injury. We performed a prospective observational study at a single American Burn Association-verified Pediatric Burn Center. A total of 94 pediatric burn subjects were enrolled and twenty-three of those subjects developed a NI with a median time to diagnosis of 8 days. Whole blood samples, collected within the first 72 hours after injury, were used to compare various markers of inflammation, immune function, and soluble proteins between those who recovered without developing an infection and those who developed a NI after burn injury. Within the first three days of burn injury, innate and adaptive immune function markers (ex vivo lipopolysaccharide-induced tumor necrosis factor alpha production capacity, and ex vivo phytohemagglutinin-induced interleukin-10 production capacity, respectively) were decreased for those subjects who developed a subsequent NI. Further analysis of soluble protein targets associated with these pathways displayed significant increases in soluble CD27, BTLA, and TIM-3 for those who developed a NI. Our findings indicate that suppression of both the innate and adaptive immune function occurs concurrently within the first 72 hours following pediatric thermal injury. At the same time, subjects who developed NI have increased soluble protein biomarkers. Soluble CD27, BTLA, and TIM-3 were highly predictive of the development of subsequent infectious complications. This study identifies early soluble protein makers that are predictive of infection in pediatric burn subjects. These findings should inform future immunomodulatory therapeutic studies.