Low-risk Staphylococcus aureus bacteremia patients do not require routine diagnostic imaging: A multicenter retrospective cohort study

BACKGROUND

Risk stratification to categorize patients with Staphylococcus aureus bacteremia (SAB) as low- or high-risk for metastatic infection may direct diagnostic evaluation and enable personalized management. We investigated the frequency of metastatic infections in low-risk SAB patients, their clinical relevance, and whether omission of routine imaging is associated with worse outcomes.

METHODS

We performed a retrospective cohort study in seven Dutch hospitals among adult patients with low-risk SAB, defined as hospital-acquired infection without treatment delay, absence of prosthetic material, short duration of bacteremia, and rapid defervescence. The primary outcome was the proportion of patients whose treatment plan changed due to detected metastatic infections, as evaluated by both the actual therapy administered and by linking a retrospectively adjudicated diagnosis to guideline-recommended treatment. Secondary outcomes were 90-day relapse-free survival, and factors associated with performing of diagnostic imaging.

RESULTS

Of 377 patients included, 298 (79%) underwent diagnostic imaging. In 15 of these 298 patients (5.0%) imaging findings during patient admission had been interpreted as metastatic infections that should extend duration of treatment. Using the final adjudicated diagnosis, 4 patients (1.3%) had clinically relevant metastatic infection. In a multilevel multivariable logistic regression analysis, 90-days relapse-free survival was similar between patients without imaging and those who underwent imaging (81.0% versus 83.6%; aOR 0.749 (95% CI 0.373-1.504).

CONCLUSION

Our study advocates risk stratification for the management of patients with SAB. Prerequisites are follow-up blood cultures, bedside ID consultation, along with critically reviewing disease evolution. Using this approach, routine imaging could be omitted in low-risk patients.

Personalised immunotherapy in sepsis: a scoping review protocol

INTRODUCTION

Sepsis, a life-threatening organ dysfunction syndrome occurring in the context of severe infections, remains a major burden on global health with high morbidity and high mortality rates. Despite recent advances in the understanding of its pathophysiology, the treatment of sepsis remains supportive of nature with few interventions specifically designed for treating this complex syndrome. The focus of sepsis trials has increasingly shifted towards targeting excessive inflammation and immunosuppression using immunomodulatory agents. However, it remains uncertain how to identify patients that could benefit from such treatment, whether treatments can be tailored to an individual's immune profile, or at which stage of the disease the intervention should be initiated. In this scoping review, we provide a comprehensive overview of current available literature on immunostimulatory and immunosuppressive therapies against sepsis.

METHODS AND ANALYSIS

The aim of this scoping review is to describe and summarise current literature evaluating immunotherapy in adult patients with sepsis. The review will be performed using the framework formulated by Arksey and O'Malley. A comprehensive literature and study collection will be executed by searching PubMed, Embase, Cochrane CENTRAL and ClinicalTrials.gov to identify clinical trials and cohort studies concerning immunotherapy in adult patients with sepsis. Screening will be performed independently and in duplicate by two reviewers who will also independently extract data into prespecified spreadsheets. We will summarise evidence in tabular format with descriptive statistics. The reported evidence will convey knowledge on the types of immunotherapies studied, and currently being studied, in adult patients with sepsis.

ETHICS AND DISSEMINATION

Approval from a medical ethics committee is not required. Once completed, the review will be submitted for publication in a peer-reviewed journal. These results will be of value to clinicians and researchers with an interest in advancing sepsis care.

Sustained inflammation, coagulation activation and elevated endothelin-1 levels without macrovascular dysfunction at 3 months after COVID-19

INTRODUCTION

Endothelial damage and thrombosis caused by COVID-19 may imperil cardiovascular health. More than a year since the WHO declared COVID-19 pandemic, information on its effects beyond the acute phase is lacking. We investigate endothelial dysfunction, coagulation and inflammation, 3 months post-COVID-19.

MATERIALS AND METHODS

A cohort study was conducted including 203 patients with prior COVID-19. Macrovascular dysfunction was assessed by measuring the carotid artery diameter in response to hand immersion in ice-water. A historic cohort of 312 subjects served as controls. Propensity score matching corrected for baseline differences. Plasma concentrations of endothelin-1 were measured in patients post-COVID-19, during the acute phase, and in matched controls. Coagulation enzyme:inhibitor complexes and inflammatory cytokines were studied.

RESULTS AND CONCLUSIONS

The prevalence of macrovascular dysfunction did not differ between the COVID-19 (18.6%) and the historic cohort (22.5%, RD -4%, 95%CI: -15-7, p = 0.49). Endothelin-1 levels were significantly higher in acute COVID-19 (1.67 ± 0.64 pg/mL) as compared to controls (1.24 ± 0.37, p < 0.001), and further elevated 3 months post-COVID-19 (2.74 ± 1.81, p < 0.001). Thrombin:antithrombin(AT) was high in 48.3%. Markers of contact activation were increased in 16-30%. FVIIa:AT (35%) and Von Willebrand Factor:antigen (80.8%) were elevated. Inflammatory cytokine levels were high in a majority: interleukin(IL)-18 (73.9%), IL-6 (47.7%), and IL-1ra (48.9%). At 3 months after acute COVID-19 there was no indication of macrovascular dysfunction; there was evidence, however, of sustained endothelial cell involvement, coagulation activity and inflammation. Our data highlight the importance of further studies on SARS-CoV-2 related vascular inflammation and thrombosis, as well as longer follow-up in recovered patients.

Functional and transcriptional differences in monocytes from children with obesity compared to children of healthy weight

Background and aim

Cardiometabolic risk accrues across the entire life course and childhood is a key epoch for effective prevention. Obesity in childhood is the most prevalent modifiable risk factor for later cardiovascular disease (CVD). Inflammatory biomarkers and innate immune capacity are increased in adults with obesity, but childhood data are scarce. We aimed to investigate (i) innate immune cell activation in children with and without obesity; and (ii) whether weight loss impacts the innate immune inflammatory phenotype.

Methods

The innate immune phenotype of Peripheral Blood Mononuclear Cells (PBMCs) from 31 children with obesity (BMI z-score&gt;2.5) and 22 children of healthy weight (−1.5≤BMIz≤1.5, sex, age and pubertal stage matched) was characterized by high dimensional flow cytometry, ex vivo stimulation assays with subsequent 27-plex cytokine measurements, and transcriptome analysis using RNA sequencing (Figure 1). Children with obesity participated to the Royal Children's Hospital Weight Management Service (median 5 years) and at follow-up, PBMCs were obtained again as well as anthropometric data and subclinical cardiovascular phenotypes.

Results

Flow cytometric analysis showed marked differences in cell composition between children with obesity and children of healthy weight. Specifically, children with obesity have significant changes in monocyte subsets and an increased expression of monocyte activation markers. Upon stimulation, monocytes of children with obesity show an increased cytokine production capacity. Finally, transcriptomic analysis shows significant differences between monocytes from obese children and healthy controls. Effects of weight loss on these immune parameters and correlations with preclinical CVD phenotypes are currently being analysed.

Conclusions

Monocytes from children with obesity have a pro-inflammatory phenotype compared to children of normal weight. Heightened inflammation may contribute to increased CVD risk later in life and may offer opportunities for early intervention.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): Dutch Scientific Organisation (NWO) - Rubicon grant to S.B. Dutch Heart Foundation - CVON IN CONTROL II to N.P.R. and D.B. Figure 1. Schematical overview of study

Adipose tissue induces trained innate immunity in patients with obesity

Introduction

Obesity is the most prevalent modifiable risk factor for atherosclerotic cardiovascular disease and is characterized as a chronic inflammatory disease. Cells of the innate immune system, especially monocytes and macrophages, play a pivotal role in the various stages of atherosclerosis, although it still remains elusive why the strong inflammatory response persists in time. We recently showed that cells of the innate immune system, such as monocytes, can adopt a long-term immunological memory. Upon brief stimulation with atherogenic stimuli, monocytes demonstrate an enhanced long-term pro-inflammatory and pro-atherogenic phenotype. This is termed trained immunity and is mediated via epigenetic and metabolic reprogramming. The clinical relevance of these findings was verified in patients with symptomatic atherosclerosis, in which circulating monocytes showed a trained immune phenotype.

Purpose

As various adipose tissue-related particles, including pro-inflammatory cytokines and fatty acids, are capable of inducing trained immunity in vitro, we hypothesized that adipose tissue from obese subjects might induce training in peripheral monocytes, thereby contributing to the increased risk of atherosclerotic CVD in these patients. In line with this hypothesis, it is unclear whether chronic inflammation sustains after a previous period of obesity despite significant weight loss.

Methods

We obtained blood from 25 patients with obesity before and 6 months after bariatric surgery. Monocyte subsets and activation phenotype were studied using flow cytometry. Cytokine production capacity of isolated PBMCs was studied after ex vivo stimulation with several infectious and metabolic stimuli and we characterized isolated monocytes using transcriptomics. Next, we obtained visceral (VAT) and subcutaneous adipose tissue (SAT) biopsies from 10 patients. Using our established in vitro model for trained immunity, we co-incubated healthy human monocytes with the adipose tissue biopsies for 24 hours in a trans-well set-up. After 24 hours, the adipose tissue was removed and monocytes were rested. On day 6, the cells were re-stimulated for 24 hours with a second stimulus and cytokine production and the transcriptome of the macrophages was analyzed.

Results

Both SAT and VAT obtained from patients with obesity can induce a long-term memory in healthy human monocytes, as demonstrated by an increased cytokine production capacity 6 days after co-incubation. Interestingly, VAT induced a higher cytokine response compared to SAT. Analysis of the inflammatory phenotype of peripheral cells before and after bariatric surgery is currently ongoing.

Conclusions

Adipose tissue-secreted metabolites, particularly secreted by VAT, have the potential to induce persistent innate immune cell activation. Our further analyses will show whether the secretion of these molecules and the activation of the innate immune system persists upon weight loss.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Dutch Heart Foundation

Sustained endothelial, coagulation and inflammatory cytokine activation without macrovascular dysfunction at 3 months after COVID-19: a reflection on SARS-CoV-2 induced thrombo-inflammation

Background

Endothelial damage caused by COVID-19 may imperil the cardiovascular health of millions. More than a year since WHO declared the COVID-19 pandemic, information on the lasting effects of this infection on the cardiovascular system beyond the acute phase is still lacking.

Purpose

To study macrovascular endothelial dysfunction and activation, coagulation and inflammation, 3 months after resolution of acute COVID-19 symptoms.

Methods

A cross-sectional observational cohort study was conducted including 203 patients with PCR confirmed COVID-19 disease, 6–20 weeks after acute COVID-19. The primary endpoint was macrovascular endothelial function, assessed by the carotid artery reactivity (CAR) test. The CAR measures the carotid artery diameter in response to hand in ice-water immersion. A historic cohort of 313 subjects served as controls. Propensity score matching was used to correct for baseline differences. Plasma endothelin-1 (ET-1), interleukin (IL)-1ra, IL-6, IL-18 were measured by ELISA. ET-1 levels were also measured in a partially overlapping COVID-19 cohort of which plasma samples were available during the acute phase. Coagulation enzyme:inhibitor complexes for thrombin:antithrombin (TAT), factor (F) IXa:AT, FVIIa:AT, FXIa:AT, FXIa:alpha 1 antitrypsin (a1AT), FXIa:C1 esterase inhibitor (C1inh), kallikrein(PKa):C1inh and von Willebrand Factor:antigen (vWF:Ag), were assessed by in house developed ELISA.

Results

After propensity score matching, the prevalence of macrovascular dysfunction did not differ between the COVID-19 (22.5%) versus the historical control cohort (18.6%, RD −3.92%, 95%-CI −15 to 7.19, p=0.49). Plasma concentrations of markers for endothelial activation were elevated (>1 SD above normal); ET-1 (64.9%), and vWF:Ag (80.8%). In controls, ET-1 levels were significantly lower as compared to COVID-19 patients during the acute phase and after 3 months. ET-1 levels were significantly higher 3 months after COVID-19 as compared to the acute phase. Cytokines were high in a majority of patients: IL-18 (73.9%), IL-6 (51.2%), and IL-1ra (48.9%). TAT and FIXa:AT, reflecting a prothrombotic state, were high in 48.3% and 29.6% of the patients, respectively. FVIIa:AT, as marker of the extrinsic pathway, was elevated (35%). Markers of contact activation were also increased: PKa:C1inh (16.3%), FXIa:AT (16.3%), FXIa:a1AT (20.7%), and FXIa:C1inh (17.7%) (picture 1).

Conclusions

At 3 months after acute COVID-19 there was no indication of macrovascular dysfunction as compared to matched historic controls; there was evidence, however, of sustained thrombo-inflammation, indicated by high circulating concentrations of ET-1, vWF:Ag, proinflammatory cytokines, and markers of coagulation (picture 2). Elevated IL-18 levels could potentially induce arterial inflammation and subsequent atherogenesis. Our data highlight the importance of further studies on SARS-CoV-2 related thrombo-inflammation, as well as longer follow-ups in recovered patients.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): This study was supported by a grant from The Netherlands Organisation for Health Research and Development (ZonMw).

Urate-induced epigenetic modifications in myeloid cells

OBJECTIVES

Hyperuricemia is a metabolic condition central to gout pathogenesis. Urate exposure primes human monocytes towards a higher capacity to produce and release IL-1β. In this study, we assessed the epigenetic processes associated to urate-mediated hyper-responsiveness.

METHODS

Freshly isolated human peripheral blood mononuclear cells or enriched monocytes were pre-treated with solubilized urate and stimulated with LPS with or without monosodium urate (MSU) crystals. Cytokine production was determined by ELISA. Histone epigenetic marks were assessed by sequencing immunoprecipitated chromatin. Mice were injected intraarticularly with MSU crystals and palmitate after inhibition of uricase and urate administration in the presence or absence of methylthioadenosine. DNA methylation was assessed by methylation array in whole blood of 76 participants with normouricemia or hyperuricemia.

RESULTS

High concentrations of urate enhanced the inflammatory response in vitro in human cells and in vivo in mice, and broad-spectrum methylation inhibitors reversed this effect. Assessment of histone 3 lysine 4 trimethylation (H3K4me3) and histone 3 lysine 27 acetylation (H3K27ac) revealed differences in urate-primed monocytes compared to controls. Differentially methylated regions (e.g. HLA-G, IFITM3, PRKAB2) were found in people with hyperuricemia compared to normouricemia in genes relevant for inflammatory cytokine signaling.

CONCLUSION

Urate alters the epigenetic landscape in selected human monocytes or whole blood of people with hyperuricemia compared to normouricemia. Both histone modifications and DNA methylation show differences depending on urate exposure. Subject to replication and validation, epigenetic changes in myeloid cells may be a therapeutic target in gout.

Reduced CXCL1 production by endogenous IL-37 expressing dendritic cells does not affect T cell activation

The dendritic cell (DC)-derived cytokine profile contributes to naive T cell differentiation, thereby directing the immune response. IL-37 is a cytokine with anti-inflammatory characteristics that has been demonstrated to induce tolerogenic properties in DC. In this study we aimed to evaluate the influence of IL-37 on DC–T cell interaction, with a special focus on the role of the chemokine CXCL1. DC were cultured from bone marrow of human IL-37 transgenic (hIL-37Tg) or WT mice. The phenotype of unstimulated and LPS-stimulated DC was analyzed (co-stimulatory molecules and MHCII by flow cytometry, cytokine profile by RT-PCR and ELISA), and T cell stimulatory capacity was assessed in mixed lymphocyte reaction. The role of CXCL1 in T cell activation was analyzed in T cell stimulation assays with anti-CD3 or allogeneic DC. The expression of the co-stimulatory molecules CD40, CD80 and CD86, and of MHCII in LPS-stimulated DC was not affected by endogenous expression of IL-37, whereas LPS-stimulated hIL-37Tg DC produced less CXCL1 compared to LPS-stimulated WT DC. T cell stimulatory capacity of LPS-matured hIL-37Tg DC was comparable to that of WT DC. Recombinant mouse CXCL1 did not increase T cell proliferation either alone or in combination with anti-CD3 or allogeneic DC, nor did CXCL1 affect the T cell production of interferon-γ and IL-17. Endogenous IL-37 expression does not affect mouse DC phenotype or subsequent T cell stimulatory capacity, despite a reduced CXCL1 production. In addition, we did not observe an effect of CXCL1 in T cell proliferation or differentiation.

The association between treatment and systemic inflammation in acromegaly

OBJECTIVE

Acromegaly is characterized by an excess of growth hormone (GH) and insulin like growth-factor 1 (IGF1), and it is strongly associated with cardiovascular diseases (CVD). Both acute and long-lasting pro-inflammatory effects have been attributed to IGF1. Previous results suggest the presence of systemic inflammation in treated patients. Here we assessed the association between treatment of acromegaly, systemic inflammation and vascular function.

DESIGN

Ex vivo cytokine production and circulating inflammatory markers were assessed in peripheral blood from treated and untreated acromegaly patients (N = 120), and compared them with healthy controls. A more comprehensive prospective inflammatory and vascular assessment was conducted in a subgroup of six treatment-naive patients with follow-up during treatment.

RESULTS

Circulating concentrations of VCAM1, E-selectin and MMP2 were higher in patients with uncontrolled disease, whereas the concentrations of IL18 were lower. In stimulated whole blood, cytokine production was skewed towards a more pro-inflammatory profile in patients, especially those with untreated disease. Prospective vascular measurements in untreated patients showed improvement of endothelial function during treatment.

CONCLUSIONS

Acromegaly patients are characterized by a pro-inflammatory phenotype, most pronounced in those with uncontrolled disease. Treatment only partially reverses this pro-inflammatory bias. These findings suggest that systemic inflammation could contribute to the increased risk of CVD in acromegaly patients.

Mimicking Behçet's disease: GM-CSF gain of function mutation in a family suffering from a Behçet's disease-like disorder marked by extreme pathergy

Behçet's disease (BD) is an inflammatory disease mainly affecting men along the ancient Silk Route. In the present study we describe a Dutch family suffering from BD-like disease with extreme pathergic responses, but without systemic inflammation. Genetic assessment revealed a combination of the human leukocyte antigen (HLA)-B*51 risk-allele together with a rare heterozygous variant in the CSF2 gene (c.130A>C, p.N44H) encoding for granulocyte-macrophage colony-stimulating factor (GM-CSF) found by whole exome sequencing. We utilized an over-expression vector system in a human hepatocyte cell line to produce the aberrant variant of GM-CSF. Biological activity of the protein was measured by signal transducer and activator of transcription 5 (STAT-5) phosphorylation, a downstream molecule of the GM-CSF receptor, in wild-type peripheral mononuclear cells (PBMCs) using flow cytometry. Increased STAT-5 phosphorylation was observed in response to mutated GM-CSF when compared to the wild-type or recombinant protein. CSF2 p.N44H results in disruption of one of the protein's two N-glycosylation sites. Enzymatically deglycosylated wild-type GM-CSF also enhanced STAT-5 phosphorylation. The patient responded well to anti-tumor necrosis factor (TNF)-α treatment, which may be linked to the capacity of TNF-α to induce GM-CSF in phorbol 12-myristate 13-acetate (PMA)-treated PBMCs, while GM-CSF itself only induced dose-dependent interleukin (IL)-1Ra production. The identified CSF2 pathway could provide novel insights into the pathergic response of BD-like disease and offer new opportunities for personalized treatment.

Sex-biased patterns shaped the genetic history of Roma

The Roma population is a European ethnic minority characterized by recent and multiple dispersals and founder effects. After their origin in South Asia around 1,500 years ago, they migrated West. In Europe, they diverged into ethnolinguistically distinct migrant groups that spread across the continent. Previous genetic studies based on genome-wide data and uniparental markers detected Roma founder events and West-Eurasian gene flow. However, to the best of our knowledge, it has not been assessed whether these demographic processes have equally affected both sexes in the population. The present study uses the largest and most comprehensive dataset of complete mitochondrial and Y chromosome Roma sequences to unravel the sex-biased patterns that have shaped their genetic history. The results show that the Roma maternal genetic pool carries a higher lineage diversity from South Asia, as opposed to a single paternal South Asian lineage. Nonetheless, the European gene flow events mainly occurred through the maternal lineages; however, a signal of this gene flow is also traceable in the paternal lineages. We also detect a higher female migration rate among European Roma groups. Altogether, these results suggest that sociocultural factors influenced the emergence of sex-biased genetic patterns at global and local scales in the Roma population through time.

Cardiac function in relation to myocardial injury in hospitalised patients with COVID-19

BACKGROUND

Previous studies have reported on myocardial injury in patients with coronavirus infectious disease 19 (COVID-19) defined as elevated cardiac biomarkers. Whether elevated biomarkers truly represent myocardial dysfunction is not known. The aim of this study was to explore the incidence of ventricular dysfunction and assess its relationship with biomarker analyses.

METHODS

This cross-sectional study ran from April 1 to May 12, 2020, and consisted of all consecutively admitted patients to the Radboud university medical centre nursing ward for COVID-19. Laboratory assessment included high-sensitivity Troponin T and N‑terminal pro-B-type natriuretic peptide (NT-proBNP). Echocardiographic evaluation focused on left and right ventricular systolic function and global longitudinal strain (GLS).

RESULTS

In total, 51 patients were included, with a median age of 63 years (range 51-68 years) of whom 80% was male. Troponin T was elevated (>14 ng/l) in 47%, and a clinically relevant Troponin T elevation (10 × URL) was found in three patients (6%). NT-proBNP was elevated (>300 pg/ml) in 24 patients (47%), and in four (8%) the NT-proBNP concentration was >1,000 pg/ml. Left ventricular dysfunction (ejection fraction <52% and/or GLS >-18%) was observed in 27%, while right ventricular dysfunction (TAPSE <17 mm and/or RV S' < 10 cm/s) was seen in 10%. There was no association between elevated Troponin T or NT-proBNP and left or right ventricular dysfunction. Patients with confirmed pulmonary embolism had normal right ventricular function.

CONCLUSIONS

In hospitalised patients, it seems that COVID-19 predominantly affects the respiratory system, while cardiac dysfunction occurs less often. Based on a single echocardiographic evaluation, we found no relation between elevated Troponin T or NT-proBNP, and ventricular dysfunction. Echocardiography has limited value in screening for ventricular dysfunction.

A systems genomics approach identifies SIGLEC15 as a susceptibility factor in recurrent vulvovaginal candidiasis

Candida vaginitis is a frequent clinical diagnosis with up to 8% of women experiencing recurrent vulvovaginal candidiasis (RVVC) globally. RVVC is characterized by at least three episodes per year. Most patients with RVVC lack known risk factors, suggesting a role for genetic risk factors in this condition. Through integration of genomic approaches and immunological studies in two independent cohorts of patients with RVVC and healthy individuals, we identified genes and cellular processes that contribute to the pathogenesis of RVVC, including cellular morphogenesis and metabolism, and cellular adhesion. We further identified SIGLEC15, a lectin expressed by various immune cells that binds sialic acid-containing structures, as a candidate gene involved in RVVC susceptibility. Candida stimulation induced SIGLEC15 expression in human peripheral blood mononuclear cells (PBMCs) and a polymorphism in the SIGLEC15 gene that was associated with RVVC in the patient cohorts led to an altered cytokine profile after PBMC stimulation. The same polymorphism led to an increase in IL1B and NLRP3 expression after Candida stimulation in HeLa cells in vitro. Last, Siglec15 expression was induced by Candida at the vaginal surface of mice, where in vivo silencing of Siglec15 led to an increase in the fungal burden. Siglec15 silencing was additionally accompanied by an increase in polymorphonuclear leukocytes during the course of infection. Identification of these pathways and cellular processes contributes to a better understanding of RVVC and may open new therapeutic avenues.

Persistent inflammation and endothelial dysfunction in patients with treated acromegaly

OBJECTIVE

Acromegaly is characterized by an excess of growth hormone (GH) and insulin-like growth factor 1 (IGF1). Cardiovascular disease (CVD) risk factors are common in acromegaly and often persist after treatment. Both acute and long-lasting pro-inflammatory effects have been attributed to IGF1. Therefore, we hypothesized that inflammation persists in treated acromegaly and may contribute to CVD risk.

METHODS

In this cross-sectional study, we assessed cardiovascular structure and function, and inflammatory parameters in treated acromegaly patients. Immune cell populations and inflammatory markers were assessed in peripheral blood from 71 treated acromegaly patients (with controlled or uncontrolled disease) and 41 matched controls. Whole blood (WB) was stimulated with Toll-like receptor ligands. In a subgroup of 21 controls and 33 patients with controlled disease, vascular ultrasound measurements were performed.

RESULTS

Leukocyte counts were lower in patients with controlled acromegaly compared to patients with uncontrolled acromegaly and controls. Circulating IL18 concentrations were lower in patients; concentrations of other inflammatory mediators were comparable with controls. In stimulated WB, cytokine production was skewed toward inflammation in patients, most pronounced in those with uncontrolled disease. Vascular measurements in controlled patients showed endothelial dysfunction as indicated by a lower flow-mediated dilatation/nitroglycerine-mediated dilatation ratio. Surprisingly, pulse wave analysis and pulse wave velocity, both markers of endothelial dysfunction, were lower in patients, whereas intima-media thickness did not differ.

CONCLUSIONS

Despite treatment, acromegaly patients display persistent inflammatory changes and endothelial dysfunction, which may contribute to CVD risk and development of CVD.

Using routine blood parameters to anticipate clinical outcomes in invasive aspergillosis

OBJECTIVE

In invasive aspergillosis (IA), monitoring response to antifungal treatment is challenging. We aimed to explore if routine blood parameters help to anticipate outcomes following IA.

METHODS

Post hoc secondary analysis of two multicenter randomized trials was performed. The Global Comparative Aspergillosis Study (GCA, n = 123) and the Combination Antifungal Study (CAS, n = 251) constituted the discovery and validation cohorts respectively. The outcome measures were response to treatment and survival to 12 weeks. Interval platelet, galactomannan index (GMI) and C-reactive protein (CRP) levels prior and during antifungal treatment were analysed using logistic regression, Kaplan-Meier survival and receiver operating characteristic (ROC) analyses.

RESULTS

The 12-week survival was 70.7% and 63.7% for the GCA and CAS cohorts respectively. In the GCA cohort, every 10 × 10⁹/L platelet count increase at week 2 and 4 improved 12-week survival odds by 6-18% (odds ratio (OR) 1.06-1.18, 95% confidence interval (CI) 1.02-1.33). Survival odds also improved 13% with every 10 mg/dL CRP drop at week 1 and 2 (OR 0.87, 95% CI 0.78-0.97). In the CAS cohort, week 2 platelet count was also associated with 12-week survival with 10% improved odds for every 10 × 10⁹/L platelet increase (OR, 1.10, 95% CI 1.04-1.15). A GMI drop of 0.1 unit was additionally found to increase the odds of treatment response by 3% at the baseline of week 0 (OR 0.97, 95% CI 0.95-0.99). Week 2 platelet and CRP levels performed better than GMI on ROC analyses for survival (area under ROC curve 0.76, 0.87 and 0.67 respectively). A baseline platelet count higher than 30 × 10⁹/L clearly identified patients with >75% survival probability.

CONCLUSIONS

Higher serial platelets were associated with overall survival while GMI trends were linked to IA treatment response. Routine and simple laboratory indices may aid follow-up of response in IA patients.

Pathophysiological role of respiratory dysbiosis in hospital-acquired pneumonia

Hospital-acquired pneumonia is a major cause of morbidity and mortality. The incidence of hospital-acquired pneumonia remains high globally and treatment can often be ineffective. Here, we review the available data and unanswered questions surrounding hospital-acquired pneumonia, discuss alterations of the respiratory microbiome and of the mucosal immunity in patients admitted to hospital, and explore potential approaches to stratify patients for tailored treatments. The lungs have been considered a sterile organ for decades because microbiological culture techniques had shown negative results. Culture-independent techniques have shown that healthy lungs harbour a diverse and dynamic ecosystem of bacteria, changing our comprehension of respiratory physiopathology. Understanding dysbiosis of the respiratory microbiome and altered mucosal immunity in patients with critical illness holds great promise to develop targeted host-directed immunotherapy to reduce ineffective treatment, to improve patient outcomes, and to tackle the global threat of resistant bacteria that cause these infections.

Heterologous effects of vaccination and trained immunity

Vaccines are applied to large populations, but only recently has research into immunologic responses and mechanisms started to increase exponentially. Some live vaccines, such as the tuberculosis vaccine bacillus Calmette-Guérin, protect against other infections nonspecifically by eliciting complex immune responses which are not specific antibody related. These heterologous effects are explained by the concept of trained immunity. This editorial introduces five narrative reviews offering recent insights on innate and adaptive immune memory towards a variety of pathogens.

Non-specific effects of BCG vaccine on viral infections

BACKGROUND

Some strains of Bacillus Calmette-Guérin (BCG) vaccine not only confer protection against disseminated forms of tuberculosis, but also reduce all-cause mortality by the induction of protection against infections with non-related pathogens.

OBJECTIVES

We review evidence for non-specific protection induced by BCG vaccination against viral infections, discuss possible mechanisms of action, and summarize implications for vaccination policies and vaccine discovery.

SOURCES

Relevant studies retrieved from PubMed and clinicaltrials.gov.

CONTENT

Numerous epidemiological, clinical and immunological studies demonstrate that BCG vaccination impacts the immune response to subsequent infections, resulting in reduced morbidity and mortality. Important lines of evidence indicating that BCG protects against viral pathogens comes from experimental studies in mice showing that BCG offers protection against various DNA and RNA viruses, including herpes and influenza viruses. Recently, the effect of BCG on an experimental viral infection in humans has been demonstrated. These effects are thought to be mediated via the induction of innate immune memory and heterologous lymphocyte activation, resulting in enhanced cytokine production, macrophage activity, T-cell responses and antibody titres.

IMPLICATIONS

The discovery of innate immune memory has greatly improved our understanding of the mechanisms underlying the non-specific effects induced by BCG vaccination. However, a full understanding of the molecular mechanisms that underlie this phenomenon is still evolving. By identifying the factors that impact the non-specific effects of BCG, we will take an important step towards novel therapeutic options and vaccination strategies, which might lead to a reduction in severe morbidity and mortality associated with viral infections.

Trained innate immunity and resistance to Mycobacterium tuberculosis infection

BACKGROUND

Some individuals, even when heavily exposed to an infectious tuberculosis patient, develop neither active nor latent tuberculosis infection (LTBI). This 'early clearance' of Mycobacterium tuberculosis is associated with a history of bacillus Calmette-Guérin (BCG) vaccination. As BCG vaccination can boost innate immune responses through a process termed 'trained immunity', we hypothesize that BCG-induced trained innate immunity contributes to early clearance of M. tuberculosis.

OBJECTIVES

We describe the epidemiological evidence and biological concepts of early clearance and trained immunity, and the possible relation between these two processes through BCG vaccination.

SOURCES

Relevant data from published reports up to November 2018 were examined in the conduct of this review.

CONTENT

Several observational studies and one recent randomized trial support the concept that boosting innate immunity contributes to protection against M. tuberculosis infection, with BCG vaccination providing approximately 50% protection. The molecular mechanisms mediating early clearance remain largely unknown, but we propose that trained immunity, characterized by epigenetic and metabolic reprogramming of innate immune cells such as monocytes or macrophages, is at least partially responsible for eliminating the mycobacteria and inducing early clearance.

IMPLICATIONS

Future studies should examine if BCG revaccination increases early clearance of M. tuberculosis through induction of trained immunity. Epigenetic or metabolic modulation may further boost BCG-induced trained innate immunity to promote tuberculosis prevention. New tuberculosis vaccine candidates should also be examined for their capacity to improve protection against M. tuberculosis infection and induce trained immunity.

Romidepsin suppresses monosodium urate crystal-induced cytokine production through upregulation of suppressor of cytokine signaling 1 expression

Background

Acute gouty arthritis currently is the most common form of inflammatory arthritis in developed countries. Treatment is still suboptimal. Dosage of urate-lowering therapy is often too low to reach target urate levels, and adherence to therapy is poor. In this study, we therefore explore a new treatment option to limit inflammation in acute gout: specific histone deacetylase (HDAC) inhibition.

Methods

Peripheral blood mononuclear cells (PBMCs) were cultured with a combination of monosodium urate crystals (MSU) and palmitic acid (C16.0) in order to activate the NLRP3 inflammasome and induce IL-1β production. HDAC inhibitors and other compounds were added beforehand with a 1-h pre-incubation period.

Results

The HDAC1/2 inhibitor romidepsin was most potent in lowering C16.0+MSU-induced IL-1β production compared to other specific class I HDAC inhibitors. At 10 nM, romidepsin decreased IL-1β, IL-1Ra, IL-6, and IL-8 production. IL-1β mRNA was significantly decreased at 25 nM. Although romidepsin increased PTEN expression, PBMCs from patients with germline mutations in PTEN still responded well to romidepsin. Romidepsin also increased SOCS1 expression and blocked STAT1 and STAT3 activation. Furthermore, experiments with bortezomib showed that blocking the proteasome reverses the cytokine suppression by romidepsin.

Conclusions

Our results show that romidepsin is a very potent inhibitor of C16.0+MSU-induced cytokines in vitro. Romidepsin upregulated transcription of SOCS1, which was shown to directly target inflammatory signaling molecules for proteasomal degradation. Inhibiting the proteasome therefore reversed the cytokine-suppressive effects of romidepsin. HDAC1/2 dual inhibition could therefore be a highly potent new treatment option for acute gout, although safety has to be determined in vivo.

Electronic supplementary material

The online version of this article (10.1186/s13075-019-1834-x) contains supplementary material, which is available to authorized users.

Role of gut microbiota in chronic low-grade inflammation as potential driver for atherosclerotic cardiovascular disease: a systematic review of human studies

A hallmark of obesity is chronic low-grade inflammation, which plays a major role in the process of atherosclerotic cardiovascular disease (ACVD). Gut microbiota is one of the factors influencing systemic immune responses, and profound changes have been found in its composition and metabolic function in individuals with obesity. This systematic review assesses the association between the gut microbiota and markers of low-grade inflammation in humans. We identified 14 studies which were mostly observational and relatively small (n = 10 to 471). The way in which the microbiome is analysed differed extensively between these studies. Lower gut microbial diversity was associated with higher white blood cell counts and high sensitivity C-reactive protein (hsCRP) levels. The abundance of Bifidobacterium, Faecalibacterium, Ruminococcus and Prevotella were inversely related to different markers of low-grade inflammation such as hsCRP and interleukin (IL)-6. In addition, this review speculates on possible mechanisms through which the gut microbiota can affect low-grade inflammation and thereby ACVD. We discuss the associations between the microbiome and the inflammasome, the innate immune system, bile acids, gut permeability, the endocannabinoid system and TMAO. These data reinforce the importance of human research into the gut microbiota as potential diagnostic and therapeutic strategy to prevent ACVD.

HDAC inhibitors modulate innate immune responses to micro-organisms relevant to chronic mucocutaneous candidiasis

Signal transducer and activator of transcription 1 (STAT-1) gain-of-function (GOF) mutations cause chronic mucocutaneous candidiasis (CMC), a disease associated with Candida albicans and Staphylococcus aureus infection. Patients suffer from dysegulated immune responses due to aberrant cell programming and function. We investigated the effect of inhibitory molecules targeting histone deacetylases (HDACi) on the immune responses of peripheral blood mononuclear cells (PBMCs) of healthy controls and patients with CMC towards microbes relevant for CMC. PBMCs cells were pretreated with HDACi and challenged with C. albicans or S. aureus. Innate and adaptive cytokines were measured in cell culture supernatants by enzyme-linked immunosorbent assay (ELISA). We assessed the effect of HDAC inhibitors on T helper type 1 (Th1) and Th17 cells and measured STAT-1 and STAT-3 phosphorylation using flow cytometry. Panobinostat, a pan-HDAC inhibitor, strongly inhibits innate and adaptive cytokines upon challenge with C. albicans or S. aureus. Specific inhibitors (entinostat or RGFP966) also had a tendency to lower production of most innate cytokines in CMC patient cells. Entinostat and RGFP966 increased the production of interleukin (IL)-22 specifically after S. aureus challenge in patient cells. In healthy and control cells, entinostat and RGFP966 treatment down-regulated STAT-1 phosphorylation while pSTAT-3 levels remained stable. HDACi modulate cytokine production in response to C. albicans and S. aureus. Pan-inhibitors lower overall cytokine production, whereas specific inhibitors confer a selective effect. Entinostat and RGFP966 are promising therapeutic candidates to treat STAT-1 GOF due to their capacity to restore IL-22 production and decrease STAT-1 phosphorylation; however, their inhibition of innate cytokines poses a possible risk to secondary infections.

A novel mutation in the TG gene (G2322S) causing congenital hypothyroidism in a Sudanese family: a case report

Background

Congenital hypothyroidism (CH) has an incidence of approximately 1:3000, but only 15% have mutations in the thyroid hormone synthesis pathways. Genetic analysis allows for the precise diagnosis.

Case presentation

A 3-week old girl presented with a large goiter, serum TSH > 100 mIU/L (reference range: 0.7–5.9 mIU/L); free T₄ < 3.2 pmol/L (reference range: 8.7–16 pmol/L); thyroglobulin (TG) 101 μg/L. Thyroid Tc-99 m scan showed increased radiotracer uptake. One brother had CH and both affected siblings have been clinically and biochemically euthyroid on levothyroxine replacement. Another sibling had normal thyroid function. Both Sudanese parents reported non-consanguinity. Peripheral blood DNA from the proposita was subjected to whole exome sequencing (WES). WES identified a novel homozygous missense mutation of the TG gene: c.7021G > A, p.Gly2322Ser, which was subsequently confirmed by Sanger sequencing and present in one allele of both parents. DNA samples from 354 alleles in four Sudanese ethnic groups (Nilotes, Darfurians, Nuba, and Halfawien) failed to demonstrate the presence of the mutant allele. Haplotyping showed a 1.71 centiMorgans stretch of homozygosity in the TG locus suggesting that this mutation occurred identical by descent and the possibility of common ancestry of the parents. The mutation is located in the cholinesterase-like (ChEL) domain of TG.

Conclusions

A novel rare missense mutation in the TG gene was identified. The ChEL domain is critical for protein folding and patients with CH due to misfolded TG may present without low serum TG despite the TG gene mutations.

Electronic supplementary material

The online version of this article (10.1186/s12881-018-0588-7) contains supplementary material, which is available to authorized users.

Towards precision medicine in sepsis: a position paper from the European Society of Clinical Microbiology and Infectious Diseases

BACKGROUND

Our current understanding of the pathophysiology and management of sepsis is associated with a lack of progress in clinical trials, which partly reflects insufficient appreciation of the heterogeneity of this syndrome. Consequently, more patient-specific approaches to treatment should be explored.

AIMS

To summarize the current evidence on precision medicine in sepsis, with an emphasis on translation from theory to clinical practice. A secondary objective is to develop a framework enclosing recommendations on management and priorities for further research.

SOURCES

A global search strategy was performed in the MEDLINE database through the PubMed search engine (last search December 2017). No restrictions of study design, time, or language were imposed.

CONTENT

The focus of this Position Paper is on the interplay between therapies, pathogens, and the host. Regarding the pathogen, microbiologic diagnostic approaches (such as blood cultures (BCs) and rapid diagnostic tests (RDTs)) are discussed, as well as targeted antibiotic treatment. Other topics include the disruption of host immune system and the use of biomarkers in sepsis management, patient stratification, and future clinical trial design. Lastly, personalized antibiotic treatment and stewardship are addressed (Fig. 1).

IMPLICATIONS

A road map provides recommendations and future perspectives. RDTs and identifying drug-response phenotypes are clear challenges. The next step will be the implementation of precision medicine to sepsis management, based on theranostic methodology. This highly individualized approach will be essential for the design of novel clinical trials and improvement of care pathways.

Bacillus Calmette-Guérin vaccination at birth and in vitro cytokine responses to non-specific stimulation. A randomized clinical trial

Several studies have shown increased in vitro cytokine responses to non-related pathogens after Bacillus Calmette-Guérin (BCG) vaccination. A total of 158 infants (80 BCG administered within 7 days of birth; 78 controls) were bled 4 days post-randomization, and at age 3 and 13 months. Geometric mean concentrations of IL-1β, TNF-α, IL-6 (24 h stimulation) and IFN-γ, IL-10, IL-17, IL-22 (96 h stimulation) in response to in vitro stimulation with RPMI, LPS, PHA, Escherichia coli, Streptococcus pneumoniae, Candida albicans and BCG were compared among BCG vaccinated children and controls. BCG vaccination did not affect in vitro cytokine production, except IFN-γ and IL-22 response to BCG. Stratifying for 'age at randomization' we found a potentiating effect of BCG on cytokine production (TNF-α, IL-6, IL-10) in the 4 days post randomization stimulations, among children who were vaccinated at age 2-7 days versus age 0-1 days. BCG vaccination did not potentiate cytokine production to non-BCG antigens. At 4 days post randomization, BCG was associated with higher cytokine production in the later randomized children.

Rare NOX3 Variants Confer Susceptibility to Agranulocytosis During Thyrostatic Treatment of Graves' Disease

Agranulocytosis is a rare and serious adverse effect of antithyroid drugs, with unknown etiology. The present study aimed to uncover genetic susceptibility and underlying mechanisms of antithyroid drug-induced agranulocytosis (ATDAC). We studied two independent families with familial Graves' disease, of which several members developed ATDAC. In addition, six sporadic ATDAC patients with Graves' disease were investigated. Whole exome sequencing analysis of affected and unaffected family members was performed to identify genetic susceptibility variants for ATDAC, followed by functional characterization of primary granulocytes from patients and unrelated healthy controls. Whole exome sequencing, cosegregation analysis, and stringent selection criteria of candidate gene variants identified NOX3 as a genetic factor related to ATDAC. Functional studies revealed increased apoptosis of methimazole-treated granulocytes from patients carrying NOX3 variants. In conclusion, genetic variants in NOX3 may confer susceptibility to antithyroid drug-induced apoptosis of granulocytes. These findings contribute to the understanding of the mechanisms underlying ATDAC.

Involvement of matrix metalloproteinases in chronic Q fever

OBJECTIVES

Chronic Q fever is a persistent infection with the intracellular Gram-negative bacterium Coxiella burnetii, which can lead to complications of infected aneurysms. Matrix metalloproteinases (MMPs) cleave extracellular matrix and are involved in infections as well as aneurysms. We aimed to study the role of MMPs in the pathogenesis of chronic Q fever.

METHODS

We investigated gene expression of MMPs through microarray analysis and MMP production with ELISA in C. burnetii-stimulated peripheral blood mononuclear cells (PBMCs) of patients with chronic Q fever and healthy controls. Twenty single nucleotide polymorphisms (SNPs) of MMP and tissue inhibitor of MMP genes were genotyped in 139 patients with chronic Q fever and 220 controls with similar cardiovascular co-morbidity. Additionally, circulating MMPs levels in patients with chronic Q fever were compared with those in cardiovascular controls with and without a history of past Q fever.

RESULTS

In healthy controls, the MMP pathway involving four genes (MMP1, MMP7, MMP10, MMP19) was significantly up-regulated in C. burnetii-stimulated but not in Escherichia coli lipopolysaccharide -stimulated PBMCs. Coxiella burnetii induced MMP-1 and MMP-9 production in PBMCs of healthy individuals (both p<0.001), individuals with past Q fever (p<0.05, p<0.01, respectively) and of patients with chronic Q fever (both p<0.001). SNPs in MMP7 (rs11568810) (p<0.05) and MMP9 (rs17576) (p<0.05) were more common in patients with chronic Q fever. Circulating MMP-7 serum levels were higher in patients with chronic Q fever (median 33.5 ng/mL, interquartile range 22.3-45.7 ng/mL) than controls (20.6 ng/mL, 15.9-33.8 ng/mL).

CONCLUSION

Coxiella burnetii-induced MMP production may contribute to the development of chronic Q fever.

Soluble TLR2 and 4 concentrations in cerebrospinal fluid in HIV/SIV-related neuropathological conditions

HIV in the central nervous system (CNS) mainly infects microglial cells which are known to express toll-like receptors (TLRs). This paper aimed to study the role of soluble TLR2 (sTLR2), sTLR4, and other inflammatory markers in cerebrospinal fluid (CSF) in HIV/Simian immunodeficiency virus (SIV)-related neurological sequelae. We determined sTLR2 and sTLR4 levels in CSF and serum/plasma of SIV-infected rhesus macaques with and without neurological sequelae, as well as in HIV-infected patients with and without cognitive impairments and Alzheimer's disease (AD) patients and matched controls. CSF cytokines and chemokines levels were analyzed in macaques as markers of neuroinflammation, while neopterin and S100B CSF concentrations were measured in HIV-infected patients as microglial and astrocyte marker, respectively. We found detectable levels of sTLR2 and sTLR4 in CSF of macaques and humans. Furthermore, CSF sTLR2 and sTLR4 concentrations were higher in SIV-infected macaques with neurological sequelae compared to those without neurological complications (p = 0.0003 and p = 0.0006, respectively). CSF IL-8 and monocyte chemoattractant protein-1 (MCP-1) levels were elevated in macaques with neurological sequelae, and a positive correlation was found between CSF levels of sTLR2/4 and IL-8 and MCP-1. Also in humans, elevated CSF sTLR4 levels were found in HIV-infected patients with cognitive impairments compared to HIV-infected patients with normal cognition (p = 0.019). Unlike CSF S100B levels, neopterin correlated positively with sTLR2 and sTLR4. No difference was found in plasma and CSF sTLR2 and sTLR4 levels between AD patients and control subjects (p = 0.26). In conclusion, CSF sTLR2 and sTLR4 may play a role in HIV/SIV-related neuroinflammation and subsequent neuropathology.

Intact interferon-γ response against Coxiella burnetii by peripheral blood mononuclear cells in chronic Q fever

OBJECTIVES

Q fever is caused by Coxiella burnetii, an intracellular bacterium that infects phagocytes. The aim of the present study was to investigate whether the C. burnetii-induced IFN-γ response is defective in chronic Q fever patients.

METHODS

IFN-γ was measured in supernatants of C. burnetii-stimulated peripheral blood mononuclear cells (PBMCs) of 17 chronic Q fever patients and 17 healthy individuals. To assess IFN-γ responses, expression profiles of IFN-γ-induced genes in C. burnetii-stimulated PBMCs were studied in six patients and four healthy individuals. Neopterin was measured in PBMC supernatants (of eight patients and four healthy individuals) and in sera (of 21 patients and 11 healthy individuals). In a genetic association study, polymorphisms in genes involved in the Th1-cytokine response were analysed in a cohort of 139 chronic Q fever patients and a cohort of 220 control individuals with previous exposition to C. burnetii.

RESULTS

IFN-γ production by C. burnetii-stimulated PBMCs from chronic Q fever patients was significantly higher than in healthy controls. Many IFN-γ response genes were strongly upregulated in PBMCs of patients. Neopterin levels were significantly higher in PBMC supernatants and sera of patients. The IL12B polymorphisms rs3212227 and rs2853694 were associated with chronic Q fever.

CONCLUSIONS

IFN-γ production, as well as the response to IFN-γ, is intact in chronic Q fever patients, and even higher than in healthy individuals. Polymorphisms in the IL-12p40 gene are associated with chronic Q fever. Thus, a deficiency in IFN-γ responses does not explain the failure to clear the infection. The genetic data suggest, however, that the IL-12/IFN-γ pathway does play a role.

The mitogenome of a 35,000-year-old Homo sapiens from Europe supports a Palaeolithic back-migration to Africa

After the dispersal of modern humans (Homo sapiens) Out of Africa, hominins with a similar morphology to that of present-day humans initiated the gradual demographic expansion into Eurasia. The mitogenome (33-fold coverage) of the Peştera Muierii 1 individual (PM1) from Romania (35 ky cal BP) we present in this article corresponds fully to Homo sapiens, whilst exhibiting a mosaic of morphological features related to both modern humans and Neandertals. We have identified the PM1 mitogenome as a basal haplogroup U6*, not previously found in any ancient or present-day humans. The derived U6 haplotypes are predominantly found in present-day North-Western African populations. Concomitantly, those found in Europe have been attributed to recent gene-flow from North Africa. The presence of the basal haplogroup U6* in South East Europe (Romania) at 35 ky BP confirms a Eurasian origin of the U6 mitochondrial lineage. Consequently, we propose that the PM1 lineage is an offshoot to South East Europe that can be traced to the Early Upper Paleolithic back migration from Western Asia to North Africa, during which the U6 lineage diversified, until the emergence of the present-day U6 African lineages.

Trained immunity: a new avenue for tuberculosis vaccine development

Adaptive immunity towards tuberculosis (TB) has been extensively studied for many years. In addition, in recent years the profound contribution of innate immunity to host defence against this disease has become evident. The discovery of pattern recognition receptors, which allow innate immunity to tailor its response to different infectious agents, has challenged the view that this arm of immunity is nonspecific. Evidence is now accumulating that innate immunity can remember a previous exposure to a microorganism and respond differently during a second exposure. Although the specificity and memory of innate immunity cannot compete with the highly sophisticated adaptive immune response, its contribution to host defence against infection and to vaccine-induced immunity should not be underestimated and needs to be explored. Here, we present the concept of trained immunity and discuss how this may contribute to new avenues for control of TB.

Association of a variable number tandem repeat in the NLRP3 gene in women with susceptibility to RVVC

Vaginal infections with Candida spp. frequently occur in women of childbearing age. A small proportion of these women experience recurrent vulvovaginal candidosis (RVVC), which is characterized by at least three episodes of infection in one year. In addition to known risk factors such as antibiotics, diabetes, or pregnancy, host genetic variation and inflammatory pathways such as the IL-1/Th17 axis have been reported to play a substantial role in the pathogenesis of RVVC. In this study, we assessed a variable number tandem repeat (VNTR) polymorphism in the NLRP3 gene that encodes a component of the inflammasome, processing the proinflammatory cytokines IL-1β and IL-18. A total of 270 RVVC patients and 583 healthy controls were analyzed, and increased diseases susceptibility was associated with the presence of the 12/9 genotype. Furthermore, functional studies demonstrate that IL-1β production at the vaginal surface is higher in RVVC patients bearing the 12/9 genotype compared to controls, whereas IL-1Ra levels were decreased and IL-18 levels remained unchanged. These findings suggest that IL-1β-mediated hyperinflammation conveyed by the NLRP3 gene plays a causal role in the pathogenesis of RVVC and may identify this pathway as a potential therapeutic target in the disease.

Coexistence of systemic lupus erythematosus, tuberous sclerosis and aggressive natural killer-cell leukaemia: coincidence or correlated?

Among patients with systemic lupus erythematosus (SLE) there is an increased risk of haematological malignancies, especially non-Hodgkin lymphoma. However, the association of SLE with aggressive CD3 negative natural killer (NK)-cell leukaemia has not been reported so far. We present a case of a 39-year-old woman with SLE, aggressive NK-cell leukaemia and tuberous sclerosis complex. The prior probability of developing the combination of these three rare diseases by coincidence is extremely low (<10(-13)). Possible underlying immunological, genetic and toxic/environmental pathways are discussed.

An Omics Perspective on Candida Infections: Toward Next-Generation Diagnosis and Therapy

Candida species can cause severe infections associated with high morbidity and mortality. Therefore, it is essential to gain more insight into the anti-fungal host defense response. The advent of omics technology and development of advanced systems biology tools has permitted to approach this in an unbiased and quantitative manner. This review summarizes the insights gained on anti-Candida immunity from genetic-, transcriptome-, proteome-, metabolome-, microbiome-, mycobiome-, and computational systems biology studies and discusses practical aspects and future perspectives.

Individualized significance of the -251 A/T single nucleotide polymorphism of interleukin-8 in severe infections

Based on the concept of the individualized nature of sepsis, we investigated the significance of the -251 A/T (rs4073) single nucleotide polymorphism (SNP) of interleukin (IL)-8 in relation to the underlying infection. Genotyping was performed in 479 patients with severe acute pyelonephritis (UTI, n = 146), community-acquired pneumonia (CAP, n = 109), intra-abdominal infections (IAI, n = 119), and primary bacteremia (BSI, n = 105) by restriction fragment length polymorphism of the polymerase chain reaction (PCR) product and compared with 104 healthy volunteers. Circulating IL-8 was measured within the first 24 h of diagnosis by an immunosorbent assay. Carriage of the AA genotype was protective from the development of UTI (odds ratio 0.38, p: 0.007) and CAP (odds ratio 0.30, p: 0.004), but not from IAI and BSI. Protection from the development of severe sepsis/septic shock was provided for carriers of the AA genotype among patients with UTI (odds ratio 0.15, p: 0.015). This was accompanied by greater concentrations of circulating IL-8 among patients with the AA genotype. It is concluded that carriage of rs4073 modifies susceptibility for severe infection in an individualized way. This is associated with a modulation of circulating IL-8.

Pattern recognition pathways leading to a Th2 cytokine bias in allergic bronchopulmonary aspergillosis patients

BACKGROUND

Allergic bronchopulmonary aspergillosis (ABPA) is characterised by an exaggerated Th2 response to Aspergillus fumigatus, but the immunological pathways responsible for this effect are unknown.

OBJECTIVE

The aim of this study was to decipher the pattern recognition receptors (PRRs) and cytokines involved in the Aspergillus-specific Th2 response and to study Aspergillus-induced responses in healthy controls and ABPA patients.

METHODS

Peripheral blood mononuclear cells (PBMCs) were stimulated with heat-killed Aspergillus conidia, various other pathogens, or PRR ligands. PRRs and cytokine pathways were blocked with PRR-blocking reagents, anti-TNF (Etanercept or Adalimumab), IL-1Ra (Anakinra) or IFNγ (IFN-gamma). ELISA and FACS were used to analyse cytokine responses.

RESULTS

Aspergillus was the only pathogen that stimulated the Th2 cytokines IL-5 and IL-13, while Gram-negative bacteria, Gram-positive bacteria, Candida albicans, chitin, β-glucan or Toll-like receptor (TLR) ligands did not. Depletion of CD4(+) cells abolished IL-13 production. Blocking complement receptor 3 (CR3) significantly reduced IL-5 and IL-13, while blocking TLR2, TLR4 or dectin-1 had no effect. ABPA patients displayed increased Aspergillus-induced IL-5 and IL-13 and decreased IFNγ production compared with healthy controls. All biological agents tested showed the capability to inhibit Th2 responses, but also decreased Aspergillus-induced IFNγ.

CONCLUSIONS AND CLINICAL RELEVANCE

Aspergillus conidia are unique in triggering Th2 responses in human PBMCs, through a CR3-dependent pathway. ABPA patients display a significantly increased Aspergillus-induced Th2/Th1 ratio that can be modulated by biologicals. These data provide a rationale to explore IFNγ therapy in ABPA as a corticosteroid-sparing treatment option, by dampening Th2 responses and supplementing the IFNγ deficiency at the same time.

A missense mutation underlies defective SOCS4 function in a family with autoimmunity

OBJECTIVE

The aim of this study was to determine the genetic and immunological defects underlying familial manifestations of an autoimmune disorder.

METHODS

Whole-exome sequencing was performed on the index patient with various manifestations of autoimmunity, including hypothyroidism, vitiligo and alopecia. Peripheral blood mononuclear cells and DNA of family members were used for functional and genetic testing of the candidate variants obtained by Sanger sequencing.

RESULTS

Exome sequencing identified 233 rare, coding and nonsynonymous variants in the index patient; five were highly conserved and affect genes that have a possible role in autoimmunity. Only a heterozygous missense mutation in the suppressor of cytokine signalling 4 gene (SOCS4) cosegregated with the autoimmune disorder in the family. SOCS4 is a known inhibitor of epidermal growth factor (EGF) receptor signalling, and functional studies demonstrated specific upregulation of EGF-dependent immune stimulation in affected family members.

CONCLUSION

We present a family with an autoimmune disorder, probably resulting from dysregulated immune responses due to mutations in SOCS4.

Defective trained immunity in patients with STAT-1-dependent chronic mucocutaneaous candidiasis

Patients with signal transducer and activator of transcription-1 (STAT1)-dependent chronic mucocutaneous candidiasis (CMC) and patients with STAT3-dependent hyper-immunoglobulin (Ig)E syndrome (HIES) display defects in T helper type 17 (Th17) cytokine production capacity. Despite this similar immune defect in Th17 function, they show important differences in the type of infections to which they are susceptible. Recently, our group reported differential regulation of STAT-1 and STAT-3 transcription factors during epigenetic reprogramming of trained immunity, an important host defence mechanism based on innate immune memory. We therefore hypothesized that STAT1 and STAT3 defects have different effects on trained immunity, and this may partly explain the differences between CMC and HIES regarding the susceptibility to infections. Indeed, while trained immunity was normally induced in cells isolated from patients with HIES, the induction of innate training was defective in CMC patients. This defect was specific for training with Candida albicans, the main pathogen encountered in CMC, and it involved a type II interferon-dependent mechanism. These findings describe the role of STAT-1 for the induction of trained immunity, and may contribute to the understanding of the differences in susceptibility to infection between CMC and HIES patients. This study could also provide directions for personalized immunotherapy in patients suffering from these immunodeficiencies.

The interleukin-1 receptor antagonist anakinra improves first-phase insulin secretion and insulinogenic index in subjects with impaired glucose tolerance

Inflammation at the level of the β cell appears to be involved in progressive β-cell dysfunction in type 2 diabetes. We assessed the effect of blocking interleukin-1 (IL-1) by anakinra [recombinant human interleukin-1 receptor antagonist (IL-1Ra)] on β-cell function. Sixteen participants with impaired glucose tolerance were treated with 150 mg anakinra daily for 4 weeks in a double blind, randomized, placebo-controlled cross-over study with a wash-out period of 4 weeks. At the end of each treatment period, oral glucose tolerance tests (OGTTs) and hyperglycaemic clamps were performed. First-phase insulin secretion improved after anakinra treatment compared with placebo, 148 ± 20 versus 123 ± 14 mU/l, respectively (p = 0.03), and the insulinogenic index was higher after anakinra treatment. These results support the concept of involvement of IL-1β in the (progressive) decrease of insulin secretion capacity associated with type 2 diabetes.

Association of autophagy-related 16-like 1 (ATG16L1) gene polymorphism with sepsis severity in patients with sepsis and ventilator-associated pneumonia

Autophagy is a highly conserved mechanism of eukaryotic cells implicated in cell homeostasis and elimination of intracellular pathogens. Functional polymorphisms in genes encoding for autophagy have been associated with susceptibility to inflammatory and infectious diseases, but data on severe infections are missing. The aim of the present study was to assess whether polymorphisms in genes encoding proteins involved in autophagy influence susceptibility to ventilator-associated pneumonia (VAP). Mechanically ventilated patients with VAP were studied. Genotyping for autophagy-related 16-like 1 (ATG16L1, rs2241880) functional polymorphism was performed using the TaqMan single-nucleotide assay. Monocytes were isolated from patients and stimulated with lipopolysaccharide (LPS). Tumor necrosis factor-α (TNF-α) was measured in the supernatants of monocytes using an enzyme-linked immunosorbent assay. Procalcitonin (PCT) was also measured in the serum of patients by an immuno-time-resolved amplified cryptate technology assay. A total of 155 patients with VAP were enrolled in the study. Carriage of the minor A allele of ATG16L1 was associated with septic shock with at least one organ failure (odds ratio (OR): 2.40, p: 0.036). TNF-α production was significantly greater among the carriers of the polymorphism presenting with at least one organ failure (p: 0.040). PCT was increased upon worsening to septic shock and organ failure only among carriers of the minor frequency A alleles. In a homogeneous cohort of septic patients with VAP, the carriage of autophagy polymorphisms predisposes to VAP severity and septic shock development. This may be related with predisposition to immunoparalysis.

The dipeptidyl peptidase-4 inhibitor vildagliptin does not affect ex vivo cytokine response and lymphocyte function in patients with type 2 diabetes mellitus

AIMS

The enzyme dipeptidyl peptidase-4 (DPP-4) is a key player in the degradation of incretin hormones that are involved in glucose metabolism. DPP-4 is also expressed on immune cells and is associated with several immunological functions. Some studies have reported increased rates of infections in patients treated with DPP-4 inhibitors. We therefore assessed whether treatment with the DPP-4 inhibitor vildagliptin affected cytokine production and T-cell differentiation.

METHODS

Patients with type 2 diabetes were treated with vildagliptin or an active comparator, acarbose, for four weeks, in a randomized cross-over trial. Blood was sampled at the end of each treatment period and peripheral blood mononuclear cells were isolated and stimulated with a broad spectrum of pattern recognition receptor agonists.

RESULTS

Serum cytokine concentrations and ex vivo cytokine production (both monocyte and T-cell derived) did not differ during treatment with vildagliptin compared to acarbose. Similarly, ex vivo relative upregulation of mRNA transcription of T-cell lineage specific transcription factors was unaffected by vildagliptin treatment.

CONCLUSIONS

These data show that a four-week treatment with vildagliptin in patients with type 2 diabetes mellitus does not result in a significant modulation of cytokine responses. This observation suggests that inhibition of DDP-4 does not lead to an increased risk of infection by diminishing cytokine production.

Autophagy is redundant for the host defense against systemic Candida albicans infections

Autophagy has been demonstrated to play an important role in the immunity against intracellular pathogens, but very little is known about its role in the host defense against fungal pathogens such as Candida albicans. Therefore, the role of autophagy for the host defense against C. albicans was assessed by complementary approaches using mice defective in autophagy, as well as immunological and genetic studies in humans. Although C. albicans induced LC3-II formation in macrophages, myeloid cell-specific ATG7(-/-) mice with defects in autophagy did not display an increased susceptibility to disseminated candidiasis. In in vitro experiments in human blood mononuclear cells, blocking autophagy modulated cytokine production induced by lipopolysaccharide, but not by C. albicans. Furthermore, autophagy modulation in human monocytes did not influence the phagocytosis and killing of C. albicans. Finally, 18 single-nucleotide polymorphisms in 13 autophagy genes were not associated with susceptibility to candidemia or clinical outcome of disease in a large cohort of patients, and there was no correlation between these genetic variants and cytokine production in either candidemia patients or healthy controls. Based on these complementary in vitro and in vivo studies, it can be concluded that autophagy is redundant for the host response against systemic infections with C. albicans.

Pulmonary infection, and not systemic inflammation, accounts for increased concentrations of exhaled nitric oxide in patients with septic shock

Nitric oxide (NO) is a key mediator in the pathophysiology of septic shock that can be measured in exhaled breath. To assess whether a pulmonary infection itself or systemic inflammation is responsible for NO production, we determined exhaled NO in ventilated patients with respiratory and non-respiratory septic shock and compared it with the concentration in ventilated intensive care patients without systemic inflammation. In addition, the change of NO production over time and correlations with haemodynamic instability were evaluated. The controls without systemic inflammation, as witnessed by the absence of systemic inflammatory response syndrome criteria and low levels of interleukin-6, had similar concentrations of NO as the patients with non-respiratory septic shock. The respiratory sepsis patients exhaled more NO than the non-respiratory sepsis patients (p = 0.05), and a time dependent decline in time in both groups (p = 0.04). Exhaled NO did not correlate with markers of disease severity, systemic inflammation and haemodynamic instability. These data indicate that the infected lungs are the source of exhaled NO.