THE EUROPEAN SHOCK SOCIETY MEETS THE IMMUNOSEP CONSORTIUM FOR PERSONALIZED SEPSIS TREATMENT.

ABSTRACT: The unacceptable high mortality of severe infections and sepsis led over the years to understand the need for adjunctive immunotherapy to modulate the dysregulated host response of the host. However, not all patients should receive the same type of treatment. The immune function may largely differ from one patient to the other. The principles of precision medicine require that some biomarker is used to capture the immune function of the host and guide the best candidate therapy. This is the approach of the ImmunoSep randomized clinical trial (NCT04990232) where patients are allocated to treatment with anakinra or recombinant interferon gamma tailored to immune signs of macrophage activation-like syndrome and immunoparalysis respectively. ImmunoSep is a first-in-class paradigm of precision medicine for sepsis. Other approaches need to consider classification by sepsis endotypes, targeting T cell and application of stem cells. Basic principle for any trial to be successful is the delivery of appropriate antimicrobial therapy as standard-of-care taking into consideration not just the likelihood for resistant pathogens but also the pharmacokinetic/pharmacodynamic mode of action of the administered antimicrobial.

Microbiology of acute bacterial skin and skin-structure infections in Greece: A proposed clinical prediction score for the causative pathogen.

Although clinical definitions of acute bacterial skin and skin-structure infection (ABSSSI) are now well established, guidance of the prediction of likely pathogens based on evidence is missing. This was a large survey of the microbiology of ABSSSIs in Greece. During the period November 2014 to December 2016, all admissions for ABSSSI in 16 departments of internal medicine or surgery in Greece were screened to determine the likely bacterial aetiology. Samples were cultured on conventional media. Expression of the SA442, mecA/mecC and SCCmec-orfX junction genes was assessed. Following univariate and forward logistic regression analysis, clinical characteristics were used to develop scores to predict the likely pathogen with a target of 90% specificity. In total, 1027 patients were screened and 633 had positive microbiology. Monomicrobial infection by Gram-positive cocci occurred in 52.1% and by Gram-negative bacteria in 20.5%, and mixed infection by Gram-positive cocci and Gram-negative bacteria in 27.3%. The most common isolated pathogens were Staphylococcus aureus and coagulase-negative staphylococci. Resistance to methicillin was 57.3% (53.5-61.1%). Three predictive scores were developed: one for infection by methicillin-resistant S. aureus, incorporating recent hospitalisation, atrial fibrillation, residency in long-term care facility (LTCF) and stroke; one for mixed Gram-positive and Gram-negative infections, incorporating localisation of ABSSSI in lumbar area, fluoroquinolone intake in last 6 days, residency in LTCF and stroke; and another for Gram-negative infection, incorporating skin ulcer presentation, peptic ulcer and solid tumour malignancy. In conclusion, methicillin-resistant staphylococci are the main pathogens of ABSSSIs. The scores developed may help to predict the likely pathogen.

Innate immunity alterations in idiopathic interstitial pneumonias and rheumatoid arthritis-associated interstitial lung diseases.

BACKGROUND: This is a prospective cohort study elucidating innate immunity in idiopathic pulmonary fibrosis (IPF), cryptogenic organizing pneumonia (COP), rheumatoid arthritis-associated usual interstitial pneumonia (RA-UIP) and RA-associated non specific interstitial pneumonia (RA-NSIP). METHODS: 23 IPF subjects, 9 COP subjects, 5 RA-UIP subjects, 8 RA-NSIP subjects were enrolled. 10 subjects were excluded. 19 healthy subjects served as controls. Blood and bronchoalveolar lavage (BAL) were obtained. Natural killer (NK) and NKT cells, NK cells apoptosis and the expression of triggering receptor expressed on myeloid cells type 1 (TREM-1) were assessed. Tumor necrosis factor-α (TNF-α) production was measured in cell cultures after stimulation with lipopolysaccharide endotoxin (LPS) and Pam3CysSK3, and in BAL. Surface expression of Toll-like receptors (TLR) 2 and 4 on peripheral blood monocytes (PBMC's) and circulating NK cells was also assessed. RESULTS: RA-NSIP had low blood NKs, marginally insignificant (p=0.07). These NKs poorly produced TNF-α after LPS stimulation. TLR's expression on NK cells was similar throughout disease groups and controls. PBMC's mainly from IPF patients exhibited low TNF-α production after LPS stimulation but not after Pam3CysSK3 stimulation, while TLR4 expression on PBMC's was found normal in all study groups. TLR2 expression on PBMC's was increased in IPF, but mainly in COP, RA-UIP and RA-NSIP (p=0.015). TREM-1 expression was significant on COP monocytes and on COP neutrophils versus controls. RA-NSIP monocytes also exhibited TREM-1 expression (p=0.07). Decreased TNF-α concentration in BAL was finally observed in IPF and RA-UIP. CONCLUSIONS: Innate immunity in the lungs and the peripheral circulation in IPF and RA-UIP are similar and more fibrotic than in RA-NSIP which is characterized by NK cell depletion and dysfunction. TREM-1 and TLR's likely affect patterns of inflammation in various interstitial lung diseases.

Alterations in the cellular component of the maternal immune system in a murine preterm delivery model.

OBJECTIVE: Investigate changes in the cellular component of maternal immune system in a murine preterm delivery (PTD) model. METHODS: C57BL/6 J mice were mated and on day 14.5 after plugging either whole blood was harvested or Escherichia coli lipopolysaccharide (LPS) was intraperitoneally injected. PTD resulted within 24 h. Ten to twelve hours after LPS injection (initiation of labor), whole blood was harvested. Annexin-V, CD3, CD4, CD8, CD80 and CD86 were counted after running through flow cytometer with gating for mononuclear cells. Control group consisted of non-pregnant mice. RESULTS: Rate of apoptosis of monocytes and lymphocytes and expression of CD80(+) and CD86(+) was increased in non-pregnant mice after LPS injection (p = 0.009, p = 0.002, p < 0.001 and p = 0.005, respectively), but remained unaltered in pregnant mice. Expression of CD3(+)/4(+) and CD3(+)/8(+) on lymphocytes was increased after LPS injection in both pregnant (p = 0.001, p = 0.011, respectively) and non-pregnant mice (p = 0.008, p < 0.001, respectively). CONCLUSIONS: Cellular component of maternal non-specific immune system is remain suppressed in pregnant mice, whereas specific immune responses of pregnant mice to infection are similar to these of non-pregnant mice.

Genetic polymorphisms within tumor necrosis factor gene promoter region: a role for susceptibility to ventilator-associated pneumonia.

Debatable findings exist among various studies regarding the impact of single nucleotide polymorphisms (SNPs) within the promoter region of the tumor necrosis factor (TNF) gene for susceptibility to infections. Their impact was investigated in a cohort of mechanically ventilated patients who developed ventilator-associated pneumonia (VAP). Two-hundred and thirteen mechanically ventilated patients who developed VAP were enrolled. Genomic DNA was extracted and SNPs at the -376, -308 and -238 position of the promoter region of the TNF gene were assessed by restriction fragment length polymorphisms. Monocytes were isolated from 47 patients when they developed sepsis and stimulated by bacterial endotoxin for the production of TNFα and of interleukin-6 (IL-6). Patients were divided into two groups; 166 patients bearing only wild-type alleles of all three studied polymorphisms; and 47 patients carrying at least one A allele of the three studied SNPs. Time between start of mechanical ventilation and advent of VAP was significantly shorter in the second group than in the first group (log-rank: 4.416, p: 0.041). When VAP supervened, disease severity did not differ between groups. Stimulation of TNFα and of IL-6 was much greater by monocytes for patients carrying A alleles. Carriage of at least one A allele of the three studied SNPs at the promoter region of the TNF-gene is associated with shorter time to development of VAP but it is not associated with disease severity. Findings may be related with a role of the studied SNPs in the production of pro-inflammatory cytokines.

Decrease of CD4-lymphocytes and apoptosis of CD14-monocytes are characteristic alterations in sepsis caused by ventilator-associated pneumonia: results from an observational study.

INTRODUCTION: The present study aimed to investigate changes of the immune response between sepsis due to ventilator-associated pneumonia (VAP) and sepsis due to other types of infections. METHODS: Peripheral venous blood was sampled from 68 patients with sepsis within 24 hours of diagnosis; 36 suffered from VAP; 32 from other nosocomial infections, all well-matched for severity, age and sex. Blood monocytes were isolated and cultured with/without purified endotoxin (lipopolysaccharide (LPS)). Estimation of tumour necrosis factor alpha (TNFalpha) and interleukin-6 (IL-6) in cultures' supernatants was done by an enzyme immunoassay. Flow cytometry was used to determine subpopulations of mononuclear cells and apoptosis. To mimic pathogenesis of VAP, mononuclear cells of healthy volunteers were progressively stimulated with increased inocula of pathogens; apoptosis was determined. RESULTS: In patients with VAP, the absolute number of CD3(+)/CD4(+) lymphocytes was significantly lower (P = 0.034) and apoptosis of isolated monocytes was increased (P = 0.007) compared to other infections. TNFalpha and IL-6 production from LPS-stimulated monocytes was lower in patients with VAP-related sepsis than with sepsis due to other infections. Apoptosis of monocytes was induced after in vitro stimulation of mononuclear cells by a mechanism mimicking VAP. CONCLUSIONS: Decrease of CD4-lymphocytes and immunoparalysis of monocytes are characteristic alterations of sepsis arising in the field of VAP.

Angiopoietin-2 is increased in septic shock: evidence for the existence of a circulating factor stimulating its release from human monocytes.

We aimed to investigate if angiopoietin-2 (Ang-2) participates in the septic process and what may be the role of monocytes as a site of release of Ang-2 in sepsis. Concentrations of Ang-2 were estimated in sera and in supernatants of monocytes derived form one already described cohort of 90 patients with septic syndrome due to ventilator-associated pneumonia (VAP). Mononuclear cells of 17 healthy volunteers were stimulated by serum of patients in the presence or absence of various intracellular pathway inhibitors. Ang-2 gene expression after stimulation was also tested. Ang-2 was higher in patients with septic shock compared to patients with sepsis, severe sepsis and controls. Ang-2 was significantly increased in non-survivors compared with survivors. Serum levels greater than 9700 pg/ml were accompanied by a 3.254 odds ratio for death (p: 0.033). Ang-2 release from monocytes of septic patients was slightly decreased after stimulation with lipopolysaccharide (LPS) of Escherichia coli O55:B5. Release of Ang-2 from healthy mononuclear cells was stimulated by serum of patients with shock but not by serum of non-shocked patients (p: 0.016). Release was decreased by LPS; increased in the presence of a TLR4 antagonist; and decreased by anti-TNF antibody. RNA transcripts of PBMCs after stimulation with serum of patients with septic shock were higher than those after LPS stimulation. It is concluded that Ang-2 is increased in serum in the event of septic shock and that its increase is related to unfavorable outcome. It seems that a circulating factor may exist in the serum of patients with septic shock that stimulates gene expression and subsequent release of Ang-2 from monocytes. TLR4 and TNFalpha modulate release of Ang-2.