Low nasal carriage of drug-resistant bacteria among medical students in Vienna

Background: Multi-drug resistant bacteria are increasing and remain a major public health challenge worldwide. In order to understand the potential role of medical students as a reservoir for circulating pathogenic bacteria and their transmission, we analysed the nasal colonisation among 86 clinically exposed medical students of the Medical University of Vienna, which is integrated into General Hospital of Vienna

Azithromycin inhibits IL-1 secretion and non-canonical inflammasome activation

Deregulation of inflammasome activation was recently identified to be involved in the pathogenesis of various inflammatory diseases. Although macrolide antibiotics display well described immunomodulatory properties, presumably involved in their clinical effects, their impact on inflammasome activation has not been investigated. We compared the influence of macrolides on cytokine induction in human monocytes. The role of intracellular azithromycin- accumulation was examined by interference with Ca++-dependent uptake. We have also analysed the signalling cascades involved in inflammasome activation, and substantiated the findings in a murine sepsis model. Azithromycin, but not clarithromycin or roxithromycin, specifically inhibited IL-1α and IL-1β secretion upon LPS stimulation. Interference with Ca++-dependent uptake abolished the cytokine-modulatory effect, suggesting a role of intracellular azithromycin accumulation in the modulatory role of this macrolide. Azithromycin’s inhibiting effects were observed upon LPS, but not upon flagellin, stimulation. Consistent with this observation, we found impaired induction of the LPS-sensing caspase-4 whereas NF-κB signalling was unaffected. Furthermore, azithromycin specifically affected IL-1β levels in a murine endotoxin sepsis model. We provide the first evidence of a differential impact of macrolides on the inflammasome/IL-1β axis, which may be of relevance in inflammasome-driven diseases such as chronic obstructive pulmonary disease or asthma

Scientific Reports / Azithromycin inhibits IL-1 secretion and non-canonical inflammasome activation

Deregulation of inflammasome activation was recently identified to be involved in the pathogenesis of various inflammatory diseases. Although macrolide antibiotics display well described immunomodulatory properties, presumably involved in their clinical effects, their impact on inflammasome activation has not been investigated. We compared the influence of macrolides on cytokine induction in human monocytes. The role of intracellular azithromycin-accumulation was examined by interference with Ca++-dependent uptake. We have also analysed the signalling cascades involved in inflammasome activation and substantiated the findings in a murine sepsis model. Azithromycin, but not clarithromycin or roxithromycin, specifically inhibited IL-1 and IL-1 secretion upon LPS stimulation. Interference with Ca++-dependent uptake abolished the cytokine-modulatory effect, suggesting a role of intracellular azithromycin accumulation in the modulatory role of this macrolide. Azithromycins inhibiting effects were observed upon LPS, but not upon flagellin, stimulation. Consistent with this observation, we found impaired induction of the LPS-sensing caspase-4 whereas NF-B signalling was unaffected. Furthermore, azithromycin specifically affected IL-1 levels in a murine endotoxin sepsis model. We provide the first evidence of a differential impact of macrolides on the inflammasome/IL-1 axis, which may be of relevance in inflammasome-driven diseases such as chronic obstructive pulmonary disease or asthma.(VLID)491092

Prevalence and Outcome of Secondary Hemophagocytic Lymphohistiocytosis Among SIRS Patients: Results from a Prospective Cohort Study

Secondary hemophagocytic lymphohistiocytosis (sHLH) is a life-threatening condition clinically presenting as SIRS (Systemic Inflammatory Response Syndrome). However, there is no comprehensive data concerning diagnostic algorithms, prevalence, outcome and biomarker performance in SIRS patients. We conducted a prospective observational cohort study on 451 consecutive patients fulfilling ≥2 SIRS criteria. The Hscore and the HLH-2004 criteria were used to determine the presence of sHLH, and the correlation of the screening-biomarkers ferritin, sCD25, and sCD163 with both scores was assessed. Out of 451 standard-care SIRS patients, five patients had high Hscores (≥169), suggesting incipient or HLH-like disease, and these patients were in urgent need for intensified therapy. However, none of these patients fulfilled five HLH-2004 criteria required for formal diagnosis. From the studied biomarkers, ferritin correlated strongest to both the HLH-2004 criteria and the Hscore (rs = 0.72, 0.41, respectively), and was the best predictor of 30-day survival (HR:1.012 per 100 μg/L, 95% CI: 1.004–1.021), when adjusted for patient’s age, sex, bacteremia and malignant underlying-disease. Also, the HLH-2004 (HR per point increase: 1.435, 95% CI: 1.1012–2.086) and the Hscore (HR per point increase:1.011, 95% CI: 1.002–1.020) were independent predictors of 30-day-survival. The Hscore detected patients in hyperinflammatory states requiring urgent therapy escalation. Degrees of hyperinflammation, as assessed by ferritin and both HLH scores, are associated with worse outcomes

BMC Nephrology / Next generation sequencing based assessment of the alloreactive T cell receptor repertoire in kidney transplant patients during rejection: a prospective cohort study

Background Kidney transplantation is the optimal treatment in end stage renal disease but the allograft survival is still hampered by immune reactions against the allograft. This process is driven by the recognition of allogenic antigens presented to T-cells and their unique T-cell receptor (TCR) via the major histocompatibility complex (MHC), which triggers a complex immune response potentially leading to graft injury. Although the immune system and kidney transplantation have been studied extensively, the subtlety of alloreactive immune responses has impeded sensitive detection at an early stage. Next generation sequencing of the TCR enables us to monitor alloreactive T-cell populations and might thus allow the detection of early rejection events. Methods/design This is a prospective cohort study designed to sequentially evaluate the alloreactive T cell repertoire after kidney transplantation. The TCR repertoire of patients who developed biopsy confirmed acute T cell mediated rejection (TCMR) will be compared to patients without rejection. To track the alloreactive subsets we will perform a mixed lymphocyte reaction between kidney donor and recipient before transplantation and define the alloreactive TCR repertoire by next generation sequencing of the complementary determining region 3 (CDR3) of the T cell receptor beta chain. After initial clonotype assembly from sequencing reads, TCR repertoire diversity and clonal expansion of T cells of kidney transplant recipients in periphery and kidney biopsy will be analyzed for changes after transplantation, during, prior or after a rejection. The goal of this study is to describe changes of overall T cell repertoire diversity, clonality in kidney transplant recipients, define and track alloreactive T cells in the posttransplant course and decipher patterns of expanded alloreactive T cells in acute cellular rejection to find an alternative monitoring to invasive and delayed diagnostic procedures. Discussion Changes of the T cell repertoire and tracking of alloreactive T cell clones after combined bone marrow and kidney transplant has proven to be of potential use to monitor the donor directed alloresponse. The dynamics of the donor specific T cells in regular kidney transplant recipients in rejection still rests elusive and can give further insights in human alloresponse.(VLID)489634

Fasting metabolism modulates the interleukin-12/interleukin-10 cytokine axis

<div><p>A crucial role of cell metabolism in immune cell differentiation and function has been recently established. Growing evidence indicates that metabolic processes impact both, innate and adaptive immunity. Since a down-stream integrator of metabolic alterations, mammalian target of rapamycin (mTOR), is responsible for controlling the balance between pro-inflammatory interleukin (IL)-12 and anti-inflammatory IL-10, we investigated the effect of upstream interference using metabolic modulators on the production of pro- and anti-inflammatory cytokines. Cytokine release and protein expression in human and murine myeloid cells was assessed after <i>toll-like</i> receptor (TLR)-activation and glucose-deprivation or co-treatment with 5′-adenosine monophosphate (AMP)-activated protein kinase (AMPK) activators. Additionally, the impact of metabolic interference was analysed in an <i>in-vivo</i> mouse model. Glucose-deprivation by 2-deoxy-D-glucose (2-DG) increased the production of IL-12p40 and IL-23p19 in monocytes, but dose-dependently inhibited the release of anti-inflammatory IL-10. Similar effects have been observed using pharmacological AMPK activation. Consistently, an inhibition of the tuberous sclerosis complex-mTOR pathway was observed. In line with our <i>in vitro</i> observations, glycolysis inhibition with 2-DG showed significantly reduced bacterial burden in a Th2-prone <i>Listeria monocytogenes</i> mouse infection model. In conclusion, we showed that fasting metabolism modulates the IL-12/IL-10 cytokine balance, establishing novel targets for metabolism-based immune-modulation.</p></div

2-DG differentially modulates pro- and anti-inflammatory cytokine secretion in human monocytes.

<p>Human monocytes were preincubated for 90 minutes with different concentrations of 2-DG or medium and then stimulated with LPS. Secretion of IL-10 (a) and IL-12p40 (b) IL-23p19 (c), IL-1β (d), IL-6 (e) TNF-α (f) was determined from 18–24 hr culture supernatants by ELISA. Pretreatment of monocytes with rapamycin (100 nM) served as control. Data are representative of 5 independent experiments and presented as % response ± SD. In unstimulated cultures cytokines were undetectable. 2-DG treatment alone induced no significant cytokine production: IL-10: 2 times below detection level, 3 times ≤ 1.4 pg/mL, IL-12p40: 4 times below detection level, 1x 3.8 pg/mL, IL-23p19: 5 times below detection level, IL-1β: 2 times below detection level, 3 times ≤ 22.2 pg/mL, IL-6: 5 times below 11.6 pg/mL, TNF-α 1x below detection level 4 times ≤ 2.8 pg/mL; Mean cytokine levels after LPS stimulation in the absence of 2-DG were: IL-10, 904 ± 1096 pg/mL; IL-12p40, 535 ± 509 pg/mL; IL-23p19, 136 ± 152 pg/mL; IL-1β, 9471 ± 10692 pg/mL; IL-6, 1608 ± 414 pg/mL; TNF-α, 1596 ± 642 pg/mL. *p ≤ 0.05, ***p ≤ 0.005.</p

Modulation of cytokine production by 2-DG in murine BMDMs.

<p>BMDMs from BALB/c mice were cultured in 6 well plates and treated with 1, 3, and 5 mM 2-DG and <i>L</i>.<i>m</i>. as indicated. IL-10 (a) and IL-12p40 (b) were determined from 20 hour culture supernatants by ELISA. *p ≤ 0.05, **p ≤ 0.01 <i>L</i>.<i>m</i>. <i>Listeria monocytogenes</i>. 2-DG treatment alone induced the following cytokine levels: IL-10: 4 times ≤ 84.5 pg/mL, IL12p40: 4 times ≤ 5.1 pg/mL.</p