Immune profiling of age and adjuvant-specific activation of human blood mononuclear cells in vitro.

Vaccination reduces morbidity and mortality due to infections, but efficacy may be limited due to distinct immunogenicity at the extremes of age. This raises the possibility of employing adjuvants to enhance immunogenicity and protection. Early IFNγ production is a hallmark of effective vaccine immunogenicity in adults serving as a biomarker that may predict effective adjuvanticity. We utilized mass cytometry (CyTOF) to dissect the source of adjuvant-induced cytokine production in human blood mononuclear cells (BMCs) from newborns (~39-week-gestation), adults (~18-63 years old) and elders (>65 years of age) after stimulation with pattern recognition receptors agonist (PRRa) adjuvants. Dimensionality reduction analysis of CyTOF data mapped the BMC compartment, elucidated age-specific immune responses and profiled PRR-mediated activation of monocytes and DCs upon adjuvant stimulation. Furthermore, we demonstrated PRRa adjuvants mediated innate IFNγ induction and mapped NK cells as the key source of TLR7/8 agonist (TLR7/8a) specific innate IFNγ responses. Hierarchical clustering analysis revealed age and TLR7/8a-specific accumulation of innate IFNγ producing γδ T cells. Our study demonstrates the application of mass cytometry and cutting-edge computational approaches to characterize immune responses across immunologically distinct age groups and may inform identification of the bespoke adjuvantation systems tailored to enhance immunity in distinct vulnerable populations.

Intravenous pentoxifylline is well tolerated in critically ill preterm infants with sepsis or necrotizing enterocolitis.

Pentoxifylline (PTX) is a candidate adjuvant medication for the treatment of sepsis and necrotizing enterocolitis in preterm infants. There is only limited data on safety and compatibility with other commonly used intravenous medications. This retrospective single-center study of 198 preterm infants (September 2012-September 2018) was performed at a level IV neonatal intensive care unit. Electronic data of all preterm infants who received pentoxifylline for sepsis or necrotizing were extracted from routine databases. We analyzed a total of 1081 PTX treatment days from 217 treatment episodes in 198 preterm infants (mean gestational age 27 weeks; mean birth weight 1060 g). At a mean daily dose of 28 mg/kg, no clinically relevant side effects were observed. PTX therapy was not associated with clinically significant changes of blood biochemistry and hematology parameters. Concomitant infusion of PTX with other common NICU medications was well tolerated, and there was no evidence of incompatibility.Conclusion: Intravenous PTX is compatible with standard NICU drugs and well tolerated in critically ill preterm infants. What is Know: •Currently, there are no evidence-based adjuvant medications available that target the harmful inflammatory host response in neonatal sepsis or necrotizing enterocolitis. •Pentoxifylline (PTX) is a candidate adjuvant medication for the treatment of sepsis and necrotizing enterocolitis in preterm infants; however, safety data are rare and PTX is currently used off-label. What is New: •Here we report on our experience in the pragmatic routine use of PTX as adjuvant therapy in 198 preterm infants with sepsis or NEC. •Concomitant infusion of PTX with other common NICU medications was well tolerated, and there was no evidence of incompatibility. No clinically relevant side effects were observed.

Cyclic AMP in human preterm infant blood is associated with increased TLR-mediated production of acute-phase and anti-inflammatory cytokines in vitro.

BACKGROUND: Preterm infants are at high risk of infection and have distinct pathogen recognition responses. Suggested mechanisms include soluble mediators that enhance cellular levels of cAMP. The aim of this study was to assess the relationship between blood cAMP concentrations and TLR-mediated cytokine production in infants during the first month of life. METHODS: Cord and serial peripheral blood samples (days of life 1-28) were obtained from a cohort of very preterm (<30 weeks' gestational age) and term human infants. Whole-blood concentrations of cAMP and FSL-1 and LPS in vitro stimulated cytokine concentrations were measured by ELISA and multiplex bead assay. RESULTS: cAMP concentrations were higher in cord than in peripheral blood, higher in cord blood of female preterm infants, and lower at Days 1 and 7 in infants exposed to chorioamnionitis, even after adjusting for leukocyte counts. TLR2 and TLR4-mediated TNF-α, IL-1ß, IL-6, IL-12p70, and IL-10 production in vitro increased over the first month of life in preterm infants and were positively correlated with leukocyte-adjusted cAMP levels and reduced by exposure to chorioamnionitis. CONCLUSIONS: The ontogeny of blood cAMP concentrations and associations with chorioamnionitis and TLR-mediated production of cytokines suggest that this secondary messenger helps shape distinct neonatal pathogen responses in early life.

Immunomodulation to Prevent or Treat Neonatal Sepsis: Past, Present, and Future.

Despite continued advances in neonatal medicine, sepsis remains a leading cause of death worldwide in neonatal intensive care units. The clinical presentation of sepsis in neonates varies markedly from that in older children and adults, and distinct acute inflammatory responses results in age-specific inflammatory and protective immune response to infection. This review first provides an overview of the neonatal immune system, then covers current mainstream, and experimental preventive and adjuvant therapies in neonatal sepsis. We also discuss how the distinct physiology of the perinatal period shapes early life immune responses and review strategies to reduce neonatal sepsis-related morbidity and mortality. A summary of studies that characterize immune ontogeny and neonatal sepsis is presented, followed by discussion of clinical trials assessing interventions such as breast milk, lactoferrin, probiotics, and pentoxifylline. Finally, we critically appraise future treatment options such as stem cell therapy, other antimicrobial protein and peptides, and targeting of pattern recognition receptors in an effort to prevent and/or treat sepsis in this highly vulnerable neonatal population.

Safety and Efficacy of Micafungin in Extremely Low Birth Weight Infants.

Little is known about the side effects of micafungin in extremely low birth weight infants. In a retrospective single-center study, 19 extremely low birth weight infants were analyzed for micafungin efficacy and safety. At a mean±standard deviation daily dosage of 7.5 ± 2.0 mg/kg, no clinically relevant side effects were observed. A significant increase of liver enzymes was reversible after treatment.

Review demonstrates that less invasive surfactant administration in preterm neonates leads to fewer complications.

Surfactant treatment of neonatal respiratory distress syndrome (RDS) was introduced in Europe during the 1990s. Meta-analyses have indicated that using less invasive surfactant administration techniques on preterm neonates receiving continuous positive airway pressure (CPAP) results in improved survival rates without bronchopulmonary dysplasia. Surfactant should be administered early and ventilator settings adapted to changing oxygen requirements and lung mechanics. Side effects including initial bradycardia, oxygen desaturation, tube obstruction and isolated cases of pulmonary haemorrhage have been reported. CONCLUSION: Less invasive surfactant therapy improves pulmonary outcomes in preterm neonates with RDS and should ideally be administered in combination with CPAP.

Pentoxifylline modulates LPS-induced hyperinflammation in monocytes of preterm infants in vitro.

BackgroundPentoxifylline (PTX), a methylxanthine derivate with immunomodulating properties, has been used as adjunctive treatment in severe neonatal sepsis. The aim of the study was to investigate the anti-inflammatory effects of PTX on Lipopolysaccharides (LPS)-stimulated monocytes of preterm neonates in vitro compared with monocytes of term infants and adult controls.MethodsWhole cord blood samples and control adult blood samples were incubated with LPS and PTX. The expression of surface markers, phagocytosis, cytokine secretion, and Toll-like receptor (TLR)4 signaling of monocytes were assessed by flow cytometry. Changes of TLR4-messenger RNA (mRNA) levels were confirmed by reverse-transcriptase PCR.ResultsThe expression of CD14, CD11b, CD64, CD71, and CD80 was downregulated by PTX in a dose-dependent manner; the greatest effect was observed on CD14 and CD11b in preterm infants. PTX markedly downregulated LPS-induced tumor necrosis factor-α, interleukin (IL)-1ß, and IL-6 levels in all age groups. Early IL-10 production was significantly downregulated by PTX in term and preterm neonates, while remaining unchanged in adults. Moreover, PTX downregulated TLR4 expression of monocytes on cellular and mRNA level, decreased signaling, and suppressed phagocytosis.ConclusionPTX downregulated TLR4 expression and signaling, thereby leading to strong anti-inflammatory properties in monocytes. Age-dependent differences were identified for CD14 and CD11b expression and IL-10 production.

Markers of endothelial cell activation and immune activation are increased in patients with severe leptospirosis and associated with disease severity.

OBJECTIVES: Previous studies concluded that haemorrhage is one of the most accurate prognostic factors of mortality in leptospirosis. Therefore, endothelial cell activation was investigated in relation to disease severity in severe leptospirosis. METHODS: Prospective cohort study of severe leptospirosis patients. Plasma levels of sE-selectin and Von Willebrand factor (VWF) were determined. Consequently, an in vitro endothelial cell model was used to assess endothelial activation after exposure to virulent Leptospira. Finally, immune activation, as a potential contributing factor to endothelial cell activation, was determined by soluble IL2-receptor (sIL-2r) and soluble Fas-ligand (sFasL) levels. RESULTS: Plasma levels of sE-selectin and VWF strongly increased in patients compared to healthy controls. Furthermore, sE-selectin was significantly elevated (203 ng/ml vs. 157 ng/ml, p < 0.05) in survivors compared to non-survivors. Endothelial cells exposed to virulent Leptospira showed increased VWF expression. E-selectin and ICAM-1 expression did not change. Immunohistochemistry revealed the presence of intracellular Leptospira and qPCR suggested replication. In vivo analysis showed that increased levels of sFasL and sIL-2r were both strongly associated with mortality. Furthermore sIL-2r levels were increased in patients that developed bleeding and significantly correlated to duration of hospital stay. DISCUSSION: Markers of endothelial activation and immune activation were associated with disease severity in leptospirosis patients.