Decreased Human Leukocyte Antigen DR on Circulating Monocytes Expression After Severe Pediatric Trauma: An Exploratory Report.

OBJECTIVES: Major trauma in adults induces immune dysfunction, with diminished expression of human leukocyte antigen-DR on circulating monocytes. No pediatric data are available. This study described the kinetics of human leukocyte antigen-DR on circulating monocytes following major pediatric trauma and relationships between human leukocyte antigen-DR on circulating monocytes and outcomes. DESIGN: Prospective observational study. SETTING: PICU and trauma unit at a tertiary-care university hospital in South Africa. PATIENTS: Children between 1 month and 13 years hospitalized for severe brain trauma or trauma with an Injury Severity Score greater than or equal to 16, from November 2016 to March 2017. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: We included 36 children. Median (interquartile range) age and Injury Severity Score were 7 years (4.9-10.5 yr) and 25 years (22.7-30 yr), respectively. Blood samples (n = 83) for standardized human leukocyte antigen-DR on circulating monocytes measurement were collected at days 1-2, 3-4, and 8-9 after injury (D1, D3, and D8, respectively). On D1, median (interquartile range) human leukocyte antigen-DR on circulating monocytes was markedly reduced relative to normal values (7,031 [5,204-11,201] antibodies per cell). There was a significant increase in human leukocyte antigen-DR on circulating monocytes from D1 to D8. Although all patients with secondary infections (n = 8; 22%) had human leukocyte antigen-DR on circulating monocytes less than 15,000 antibodies per cell at D3, human leukocyte antigen-DR on circulating monocytes levels were not associated with the occurrence of secondary infections (p = 0.22). At D3, human leukocyte antigen-DR on circulating monocytes was significantly higher in patients discharged home (n = 21) by Day 30 after trauma compared with those who died or were still hospitalized (n = 14) (p = 0.02). CONCLUSIONS: Pediatric severe trauma induced an early and dramatic decrease in human leukocyte antigen-DR on circulating monocytes expression. This alteration of innate immunity was not associated with the occurrence of secondary infection, possibly due to a lack of statistical power. However, human leukocyte antigen-DR on circulating monocytes at Day 3 is a potential indicator of those at high risk of secondary infection and worse outcomes.

Occurrence of marked sepsis-induced immunosuppression in pediatric septic shock: a pilot study.

BACKGROUND: While the process of sepsis-induced immunosuppression is now well described in adults, very little information is available on immune functions in pediatric sepsis. The current study investigated this in children with septic shock by performing immunomonitoring, including both innate (monocyte human leukocyte antigen-DR, mHLA-DR, expression) and adaptive immunity (lymphocyte subsets count), as well as cytokine concentrations (IL-6, IL-8, IL-10, IL-1Ra, TNF-α, IFN-γ). Subsequent objectives were to assess the associations between inflammatory response, potential immunosuppression and secondary acquired infection occurrence. METHODS: Single-center prospective observational study, including children aged between 1 month and 18 years admitted to pediatric intensive care unit (PICU) for septic shock. Age-matched controls were children hospitalized for elective surgery without any infectious criteria. Blood was sampled at day 1-2, 3-5, and 7-9 after sepsis onset. mHLA-DR and lymphocyte subsets count were measured by flow cytometry and cytokine concentrations by Luminex technology. RESULTS: A total of 26 children and 30 controls were included. Patients had lymphopenia, and mHLA-DR levels were significantly lower than controls at each time point (p < 0.0001). All cytokines peaked at day 1-2. Children with secondary acquired infection had lower day 3-5 mHLA-DR and higher pro-inflammatory cytokine concentrations (IL-6, IL-8 and TNF-α) at day 1-2 compared to children without secondary acquired infection. CONCLUSIONS: The higher initial inflammatory cytokine production was, the more innate immunity was altered, while evaluated by low mHLA-DR expression. Children with decreased mHLA-DR expression developed more secondary acquired infections. Upon confirmation in multicenter cohorts, these results pave the way for immunostimulation for the most immunosuppressed children in order to prevent nosocomial infections in PICU. Trial registration PedIRIS study NCT02848144. Retrospectively registered 28 July 2016.

Refractory septic shock in children: a European Society of Paediatric and Neonatal Intensive Care definition.

PURPOSE: Although overall paediatric septic shock mortality is decreasing, refractory septic shock (RSS) is still associated with high mortality. A definition for RSS is urgently needed to facilitate earlier identification and treatment. We aim to establish a European society of paediatric and neonatal intensive care (ESPNIC) experts' definition of paediatric RSS. METHODS: We conducted a two-round Delphi study followed by an observational multicentre retrospective study. One hundred and fourteen paediatric intensivists answered a clinical case-based, two-round Delphi survey, identifying clinical items consistent with RSS. Multivariate analysis of these items in a development single-centre cohort (70 patients, 30 % mortality) facilitated development of RSS definitions based on either a bedside or computed severity score. Both scores were subsequently tested in a validation cohort (six centres, 424 patients, 11.6 % mortality). RESULTS: From the Delphi process, the draft definition included evidence of myocardial dysfunction and high blood lactate levels despite high vasopressor treatment. When assessed in the development population, each item was independently associated with the need for extracorporeal life support (ECLS) or death. Resultant bedside and computed septic shock scores had high discriminative power against the need for ECLS or death, with areas under the receiver operating characteristics curve of 0.920 (95 % CI 0.89-0.94), and 0.956 (95 % CI 0.93-0.97), respectively. RSS defined by a bedside score equal to or higher than 2 and a computed score equal to or higher than 3.5 was associated with a significant increase in mortality. CONCLUSIONS: This ESPNIC definition of RSS accurately identifies children with the most severe form of septic shock.