SARS-CoV-2 infection induces a long-lived pro-inflammatory transcriptional profile

BACKGROUND

The immune response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in COVID-19 patients has been extensively investigated. However, much less is known about the long-term effects of infection in patients and how it could affect the immune system and its capacity to respond to future perturbations.

METHODS

Using a targeted single-cell multiomics approach, we have recently identified a prolonged anti-inflammatory gene expression signature in T and NK cells in type 1 diabetes patients treated with low-dose IL-2. Here, we investigated the dynamics of this signature in three independent cohorts of COVID-19 patients: (i) the Oxford COVID-19 Multi-omics Blood Atlas (COMBAT) dataset, a cross-sectional cohort including 77 COVID-19 patients and ten healthy donors; (ii) the INCOV dataset, consisting of 525 samples taken from 209 COVID-19 patients during and after infection; and (iii) a longitudinal dataset consisting of 269 whole-blood samples taken from 139 COVID-19 patients followed for a period of up to 7 months after the onset of symptoms using a bulk transcriptomic approach.

RESULTS

We discovered that SARS-CoV-2 infection leads to a prolonged alteration of the gene expression profile of circulating T, B and NK cells and monocytes. Some of the genes affected were the same as those present in the IL-2-induced anti-inflammatory gene expression signature but were regulated in the opposite direction, implying a pro-inflammatory status. The altered transcriptional profile was detected in COVID-19 patients for at least 2 months after the onset of the disease symptoms but was not observed in response to influenza infection or sepsis. Gene network analysis suggested a central role for the transcriptional factor NF-κB in the regulation of the observed transcriptional alterations.

CONCLUSIONS

SARS-CoV-2 infection causes a prolonged increase in the pro-inflammatory transcriptional status that could predispose post-acute patients to the development of long-term health consequences, including autoimmune disease, reactivation of other viruses and disruption of the host immune system-microbiome ecosystem.

CD56bright natural killer cells preferentially kill proliferating CD4+ T cells

Human CD56br natural killer (NK) cells represent a small subset of CD56+ NK cells in circulation and are largely tissue-resident. The frequency and number of CD56br NK cells in blood has been shown to increase following administration of low-dose IL-2 (LD-IL2), a therapy aimed to specifically expand CD4+ regulatory T cells (Tregs). Given the potential clinical application of LD-IL-2 immunotherapy across several immune diseases, including the autoimmune disease type 1 diabetes, a better understanding of the functional consequences of this expansion is urgently needed. In this study, we developed an in vitro co-culture assay with activated CD4+ T cells to measure NK cell killing efficiency. We show that CD56br and CD56dim NK cells show similar efficiency at killing activated CD4+ conventional T (Tconv) and Treg cell subsets. However, in contrast to CD56dim cells, CD56br NK cells preferentially target highly proliferative cells. We hypothesize that CD56br NK cells have an immunoregulatory role through the elimination of proliferating autoreactive CD4+ Tconv cells that have escaped Treg suppression. These results have implications for the interpretation of current and future trials of LD-IL-2 by providing evidence for a new, possibly beneficial immunomodulatory mechanism of LD-IL-2-expanded CD56br NK cells.

Antifungal effect of (R) and (S)-citronellal enantiomers and their predictive mechanism of action on Candida albicans from voriconazole-resistant onychomycoses

Onychomycosis is the most common disease affecting the nail unit and accounts for at least 50% of all nail diseases. In addition, Candida albicans is responsible for approximately 70% of onychomycoses caused by yeasts. This study investigated the antifungal effect of (R) and (S)-citronellal enantiomers, as well as its predictive mechanism of action on C. albicans from voriconazole-resistant onychomycoses. For this purpose, in vitro broth microdilution and molecular docking techniques were applied in a predictive and complementary manner to the mechanisms of action. The main results of this study indicate that C. albicans was resistant to voriconazole and sensitive to the enantiomers (R) and (S)-citronellal at a dose of 256 and 32 µg/mL respectively. In addition, there was an increase in the minimum inhibitory concentration (MIC) of the enantiomers in the presence of sorbitol and ergosterol, indicating that these molecules possibly affect the integrity of the cell wall and cell membrane of C. albicans. Molecular docking with key biosynthesis proteins and maintenance of the fungal cell wall and plasma membrane demonstrated the possibility of (R) and (S)-citronellal interacting with two important enzymes: 1,3-β-glucan synthase and lanosterol 14α-demethylase. Therefore, the findings of this study indicate that the (R) and (S)-citronellal enantiomers are fungicidal on C. albicans from onychomycoses and probably these substances cause damage to the cell wall and cell membrane of these micro-organisms possibly by interacting with enzymes in the biosynthesis of these fungal structures.

Neutrophils and emergency granulopoiesis drive immune suppression and an extreme response endotype during sepsis

Sepsis arises from diverse and incompletely understood dysregulated host response processes following infection that leads to life-threatening organ dysfunction. Here we showed that neutrophils and emergency granulopoiesis drove a maladaptive response during sepsis. We generated a whole-blood single-cell multiomic atlas (272,993 cells, n = 39 individuals) of the sepsis immune response that identified populations of immunosuppressive mature and immature neutrophils. In co-culture, CD66b⁺ sepsis neutrophils inhibited proliferation and activation of CD4⁺ T cells. Single-cell multiomic mapping of circulating hematopoietic stem and progenitor cells (HSPCs) (29,366 cells, n = 27) indicated altered granulopoiesis in patients with sepsis. These features were enriched in a patient subset with poor outcome and a specific sepsis response signature that displayed higher frequencies of IL1R2⁺ immature neutrophils, epigenetic and transcriptomic signatures of emergency granulopoiesis in HSPCs and STAT3-mediated gene regulation across different infectious etiologies and syndromes. Our findings offer potential therapeutic targets and opportunities for stratified medicine in severe infection.

Effect of Salivary Flow on Bleached Enamel Roughness and Mineral Content: an In Situ and In Vitro Study

This study aimed to evaluate the effect of human saliva in vitro and salivary flow in situ on the roughness and mineral content of bleached enamel. Dental specimens were divided into five groups (n=15): not bleached (NB); bleached (35% hydrogen peroxide) and exposed to distilled water (DW); human saliva in vitro (IV); normal salivary flow in situ (NSF); and low salivary flow (LSF) in situ. Enamel roughness (Ra, Rz) and calcium/phosphorus contents were evaluated with laser profilometry and energy-dispersive spectroscopy, respectively, at baseline (T1), after bleaching (T2), and after seven days (T3). Salivary pH and buffer capacity were evaluated with colorimetric strips and salivary calcium and phosphorus with absorbance spectrophotometry. Data were analyzed with non-parametric tests and linear regression (α=0.05). After contact with saliva, Ra and Rz of LSF=DW>IV=NSF=NB was found. For DW and LSF, the roughness of T1<T2=T3 was found. For IV, T1<T3<T2; for NSF, T1=T3<T2. Enamel calcium/phosphorus content did not change with bleaching or with saliva contact (p≥0.05). Buffer capacity and calcium concentration did not differ between LSF and NSF. Phosphorus was higher, and pH was lower in LSF. Ra and Rz were, respectively, 0.14 and 1.95 lower with NSF than LSF. The conclusions were that NSF in situ and human saliva in vitro recovered original enamel roughness. The experimental conditions did not affect enamel mineral content. Recovery of bleached enamel roughness was higher in NSF when compared to LSF, regardless of salivary pH, calcium and phosphorus concentrations, and buffer capacity.

Significance and distribution of aortic valve calcium score before TAVI

Introduction

Aortic valve calcium scoring by multislice computed tomography (MSCT) is an alternative load independent assessment of aortic stenosis severity. Recent studies have further demonstrated that aortic valve calcification load is related to adverse outcomes during and after transcatheter aortic valve implantation (TAVI), however reference values in this population are uncertain. This study aimed to assess aortic valve calcium in P referred for TAVI.

Methods

Retrospective analysis of consecutive patients (P) submitted to TAVI between 2014 and 2020 in a tertiary care centre. Clinical and echocardiographic characteristics, along with MSCT-derived aortic valve calcium score were collected.

Results

A total of 467 P were included, 57% female, median age 83 (9) years (minimum 45 and maximum 95 years-old). The prevalence of hypertension, dyslipidemia and diabetes was 83%, 69% and 36%, respectively. Chronic renal failure was present in 51%, atrial fibrillation in 34% and peripheral artery disease in 14%.

Considering the 346 P with aortic valve calcification quantified by MSCT, median calcium score was 2161 (1761) AU. Age did not correlate with valvular calcification (r=0.043, p=0.422). Male gender showed significantly higher calcium score (2800 (2093) vs 1850 (1584), p&lt;0.001) (Figs. 1 and 2).

11P had bicuspid aortic valve disease, with this population being younger (75 (16) vs 83 (8) years, p=0.001), nonetheless displaying higher aortic valve calcium load (2800 (2599) vs 2112 (1788), p=0.025). A weak but statistically significant correlation between calcium score and maximum (r=0.366, p&lt;0.001) and mean gradients (r=0.387, p&lt;0.001) and aortic valve area (r=−0.120, p=0.047) was demonstrated. Valvular calcification was not significantly different in P with reduced ejection fraction (&lt;50%) (p=0.388).

Conclusion

There are significant differences in aortic valve calcium score between men and women referred for TAVI. Higher maximum and mean gradients were associated with increasing valvular calcification. Age and left ventricle ejection fraction were not related. P with bicuspid aortic valve have distinct calcification characteristics. As calcification burden may influence preprocedural planning, this parameter should be incorporated in the general work-up and reference values in this population should be known.

Funding Acknowledgement

Type of funding sources: None.

Artificial intelligence-enabled comprehensive coronary phenotyping in patients with suspected CAD

Introduction

The capabilities of artificial intelligence (AI) are rapidly progressing and the research community is getting increasingly interested in its possibilities. AI algorithms are able to work continuously and at high speed, reducing human workload and saving time that physicians can spend on more complex data or rarer cases. However, many clinical AI applications are currently only used in a research setting and lack proper testing and validation.

Objectives

This study aimed to determine the accuracy and performance of a novel AI-based software tool for CCTA analysis compared to conventional expert evaluation.

Methods

We evaluated 100 CCTA exams from a cohort of symptomatic patients with mild-to-moderately abnormal non-invasive ischemia test. Stenosis severity assessed by AI-based analysis (automatic evaluation, AEv) was compared with a level III expert CCTA interpretation (manual evaluation, MEv). AI-based analysis reported exact % stenosis and obstructive CAD was considered if maximal stenosis was ≥50%. Plaque phenotype was also estimated using AI algorithms.

Results

The study cohort was as follows: 52% male, mean age 68±10 years. The prevalence of hypertension, dyslipidemia and diabetes was 77%, 81% and 23%, respectively, and 10-year cardiovascular risk was 19±10% as predicted by Framingham risk score. Typical angina was present in 33%, of which 67% had a Canadian Cardiovascular Society angina grade ≥2.

Overall prevalence of obstructive CAD determined by MEv and AEv was 25% and 21%, respectively, with a significant association between both assessments (p&lt;0.001). When compared to MEv as reference, AEv method performed with a sensitivity, specificity, positive and negative predictive values of 0.56, 0.91, 0.58 and 0.86, respectively. Area under the curve was 0.871 (p&lt;0.001) demonstrating high accuracy.

AEv atherosclerosis quantification revealed significant differences between patients with and without obstructive CAD according to MEv: median total plaque volume (569 vs 115 mm3, p&lt;0.001), calcified plaque volume (297 vs 19 mm3, p&lt;0.001), non-calcified plaque volume (235 vs 71 mm, p&lt;0.001), low-density non-calcified plaque volume (2.8 vs 1.0 mm3, p=0.023) and percent atheroma volume (16.1 vs 3.8 mm3, p&lt;0.001).

Conclusion

In patients with suspected CAD and mild-to-moderately abnormal ischemia tests, a diagnostic strategy using AEv as a gatekeeper is effective, providing a quantitative stenosis evaluation with similar diagnostic performance for obstructive CAD when compared to MEv. AI-enabled approach additionally allows a fully automated quantification of coronary plaque volumes and composition, which would further enhance risk stratification.

Funding Acknowledgement

Type of funding sources: None.

Single-cell multi-omics analysis reveals IFN-driven alterations in T lymphocytes and natural killer cells in systemic lupus erythematosus

Background: The characterisation of the peripheral immune system in the autoimmune disease systemic lupus erythematosus (SLE) at the single-cell level has been limited by the reduced sensitivity of current whole-transcriptomic technologies. Here we employ a targeted single-cell multi-omics approach, combining protein and mRNA quantification, to generate a high-resolution map of the T lymphocyte and natural killer (NK) cell populations in blood from SLE patients.

Methods: We designed a custom panel to quantify the transcription of 534 genes in parallel with the expression of 51 surface protein targets using the BD Rhapsody AbSeq single-cell system. We applied this technology to profile 20,656 T and NK cells isolated from peripheral blood from an SLE patient with a type I interferon (IFN)-induced gene expression signature (IFN ^hi), and an age- and sex- matched IFN ^low SLE patient and healthy donor.

Results: We confirmed the presence of a rare cytotoxic CD4 ⁺ T cell (CTL) subset, which was exclusively present in the IFN ^hi patient. Furthermore, we identified additional alterations consistent with increased immune activation in this patient, most notably a shift towards terminally differentiated CD57 ⁺ CD8 ⁺ T cell and CD16 ⁺ NK ^dim phenotypes, and the presence of a subset of recently-activated naïve CD4 ⁺ T cells.

Conclusions: Our results identify IFN-driven changes in the composition and phenotype of T and NK cells that are consistent with a systemic immune activation within the IFN ^hi patient, and underscore the added resolving power of this multi-omics approach to identify rare immune subsets. Consequently, we were able to find evidence for novel cellular peripheral biomarkers of SLE disease activity, including a subpopulation of CD57 ⁺ CD4 ⁺ CTLs.

Epicardial fat volume improves prediction of adverse clinical events

Funding Acknowledgements

Type of funding sources: None.

Introduction

Recent studies have demonstrated the potential of epicardial fat volume (EFV) to predict obstructive coronary artery disease (CAD), however its impact in clinical outcomes remains elusive.

Objectives

To assess the association between EFV and demo­graphic and morphometric data, coronary atherosclerotic burden and adverse events in a population of patients (pts) referred for coronary computed tomography angiography (CTA).

­Methods: Retrospective analysis of pts without known CAD referred for coronary CTA in a single tertiary care centre. A standardized protocol for quantification of EFV, thoracic fat volume (TFV), coronary artery calcification (CAC) and coronary angiography was performed. Endpoint was composite of cardiovascular death, nonfatal myocardial infarction and urgent hospitalization leading to revascularization at 12 months.

Results

72 pts were included, 58% male, mean age 67 ± 9 years. The prevalence of hypertension, dyslipidemia and diabetes was 75%, 82% and 24%, respectively. Median EFV was 101 (68) ml and total TFV 1504 (694) ml. EFV was directly related with age (rs= 0.42, p &lt;0.001), male sex (135 ± 50 vs 78 ± 30, p &lt;0.001), body mass index (rs= 0.32, p= 0.008) and TFV (rs= 0.27, p= 0.025). A positive correlation with CAC (rs= 0.47, p &lt;0.001) and a significant association with CAD (116 ± 50 vs 90 ± 37, p= 0.029) and obstructive CAD (141 ± 60 vs 97 ± 39, p= 0.031) were demonstrated. Composite endpoint was observed in 13 pts (18%). After adjusting for all considered confounders, EFV remained an independent predictor of adverse events (OR: 1.015, 95%CI: 1.003-1.027, p= 0.041). ROC analysis of EFV (AUC 0.751, p = 0.005) allowed to estimate that EFV &gt;124 ml had a sensibility and specificity to predict clinical outcomes of 69% and 71%, respectively.

Conclusion

EFV positively relates to coronary atherosclerotic burden. This study also advocates that EFV may improve risk stratification for clinical outcomes. Larger studies are required to evaluate these results. Abstract Figure 1

An immunodominant NP105-113-B*07:02 cytotoxic T cell response controls viral replication and is associated with less severe COVID-19 disease

NP105-113-B*07:02-specific CD8+ T cell responses are considered among the most dominant in SARS-CoV-2-infected individuals. We found strong association of this response with mild disease. Analysis of NP105-113-B*07:02-specific T cell clones and single-cell sequencing were performed concurrently, with functional avidity and antiviral efficacy assessed using an in vitro SARS-CoV-2 infection system, and were correlated with T cell receptor usage, transcriptome signature and disease severity (acute n = 77, convalescent n = 52). We demonstrated a beneficial association of NP105-113-B*07:02-specific T cells in COVID-19 disease progression, linked with expansion of T cell precursors, high functional avidity and antiviral effector function. Broad immune memory pools were narrowed postinfection but NP105-113-B*07:02-specific T cells were maintained 6 months after infection with preserved antiviral efficacy to the SARS-CoV-2 Victoria strain, as well as Alpha, Beta, Gamma and Delta variants. Our data show that NP105-113-B*07:02-specific T cell responses associate with mild disease and high antiviral efficacy, pointing to inclusion for future vaccine design.

Left ventricular noncompaction: the importance of identifying high-risk patients within the scope of left ventricular hypertrabeculation

Introduction

Prominent left ventricular (LV) trabeculation is frequently encountered, however LV noncompaction (LVNC) criteria are not always fulfilled. The clinical and prognostic significance of these findings remains unclear.

Objectives

To characterize the patients (P) with echocardiographic suspicion of LVNC and to assess clinical outcomes.

Methods

Retrospective single-centre study that included all echocardiograms between January 2018 and June 2020 perceiving LV hypertrabeculation. The cohort underwent diagnostic assessment for LVNC by Chin and Jenni criteria. Baseline characteristics were evaluated. Composite endpoint of cardiovascular death, heart failure (HF) hospitalization, ventricular arrythmias (VA) and nonfatal stroke was considered.

Results

51P, 75% male, mean age 50±18 years. 35P (69%) had associated heart conditions, of which 57% had other known cardiomyopathy (mainly dilated cardiomyopathy), 14% congenital, 26% ischemic and 3% valvular heart disease. 2P were in postpartum period and 1P was an athlete. Family history of cardiomyopathy was present in 8P (16%). 12P underwent genetic testing, with TTN and MYH7 mutations being the most frequently detected. Prior clinical HF was reported in 53%, previous stroke in 14%, and non-sustained and sustained VA in 24% and 4%, respectively. Mean NYHA classification was 1.8±0.7, with 31% being asymptomatic.

The prevalence of LVNC by Chin criteria was 31% and by Jenni criteria was 55%. 32P (63%) met at least one LVNC criteria. This group was younger (45±18 vs 59±15, p=0.004), had higher NT-proBNP levels (3644±2819 vs 389±640, p=0.048) and QRS fragmentation (59% vs 21%, p=0.027). Significantly higher LV end-diastolic volume (84 (41) vs 64 (28)ml/m2, p=0.008) and end-systolic volume (51 (37) vs 35 (20)ml/m2, p=0.004), along with lower LV ejection fraction (39±12 vs 49±13%, p=0.009) and global longitudinal strain (−11±5 vs −17±4%, p=0.003) were noticed. P who met LVNC criteria also had higher number of affected LV segments (6.4±1.8 vs 4.2±1.6, p&lt;0.001).

Over a mean follow-up of 18±9 months, the incidence of composite endpoint was 35%. Univariate Cox analysis showed a significant association between the presence of LVNC criteria and adverse outcomes (HR: 5.108, 95% CI: 1.682–11.236, p=0.030) (Fig. 1).

Conclusion

LV hypertrabeculation can be encountered in a variety of clinical scenarios and often overlaps with other heart diseases. P satisfying criteria for LVNC had more impairment in LV performance and worse clinical outcomes.

Funding Acknowledgement

Type of funding sources: None. Figure 1

Impact of COVID-19 in adult patients with congenital heart disease

Background

COVID-19 is responsible for a worldwide pandemic, causing more than 13 000 deaths to date in Portugal. Data already exists regarding the increased risk of adverse events in patients with cardiovascular diseases, however the impact of SARS-CoV-2 infection in patients (P) with congenital heart disease (CHD) is still under investigation.

Aims

To evaluate the impact of COVID-19 in adult patients with congenital heart disease in our tertiary centre

Methods

Adult patients seen at the CHD outpatient's clinic at a tertiary centre, who became infected with SARS-CoV-2 infection up to February 2021 were included. Assessment of patients' symptoms, need for hospitalization and admission in an intensive care unit was assessed based on medical records.

Results

We identified 36 patients (pts) with COVID-19 infection. Symptoms were present in 31 (86%). The median age was 39 (32–49) years, 58% were females. Seven P (19%) had complex cyanotic disease; three (8%) Tetralogy of Fallot; three (8%) transposition of great arteries (one after Senning procedure and 2 after arterial switch); six (14%) right ventricle obstacle; two (8%) atrioventricular canal defect; four (11%) atrial septal defect; five (14%) ventricular septal defect; five (14%) aortic coarctation; two aortopathies (one submitted do David procedure); one subaortic stenosis; two (6%) had Eisenmenger syndrome. The majority (61%) of P had previous surgery and 58% were at New York Heart Association class of I. Mild symptoms were reported by 24 P (67%). Seven adults experienced moderate symptoms (dyspnea and hypoxia) that led to hospitalization for oxygen therapy, although none required mechanical ventilation. One death was reported. There was a significant association between the gravity of CHD and hospitalizations (p=0.012).

Conclusion

Our pts had mainly mild to moderate symptoms and did not appear to have a disproportionately negative outcome; the need for hospitalization was more frequent in patients with higher CHD gravity. These findings are in line with the emerging data regarding COVID-19 in CHD P, and may be in part explained by the patient's young age and functional status.

Funding Acknowledgement

Type of funding sources: None.

Interferon-Gamma-Producing CD8+ Tissue Resident Memory T Cells Are a Targetable Hallmark of Immune Checkpoint Inhibitor-Colitis

BACKGROUND & AIMS

The pathogenesis of immune checkpoint inhibitor (ICI)-colitis remains incompletely understood. We sought to identify key cellular drivers of ICI-colitis and their similarities to idiopathic ulcerative colitis, and to determine potential novel therapeutic targets.

METHODS

We used a cross-sectional approach to study patients with ICI-colitis, those receiving ICI without the development of colitis, idiopathic ulcerative colitis, and healthy controls. A subset of patients with ICI-colitis were studied longitudinally. We applied a range of methods, including multiparameter and spectral flow cytometry, spectral immunofluorescence microscopy, targeted gene panels, and bulk and single-cell RNA sequencing.

RESULTS

We demonstrate CD8⁺ tissue resident memory T (T_RM) cells are the dominant activated T cell subset in ICI-colitis. The pattern of gastrointestinal immunopathology is distinct from ulcerative colitis at both the immune and epithelial-signaling levels. CD8⁺ T_RM cell activation correlates with clinical and endoscopic ICI-colitis severity. Single-cell RNA sequencing analysis confirms activated CD8⁺ T_RM cells express high levels of transcripts for checkpoint inhibitors and interferon-gamma in ICI-colitis. We demonstrate similar findings in both anti-CTLA-4/PD-1 combination therapy and in anti-PD-1 inhibitor-associated colitis. On the basis of our data, we successfully targeted this pathway in a patient with refractory ICI-colitis, using the JAK inhibitor tofacitinib.

CONCLUSIONS

Interferon gamma-producing CD8⁺ T_RM cells are a pathological hallmark of ICI-colitis and a novel target for therapy.

Single-cell multi-omics analysis reveals IFN-driven alterations in T lymphocytes and natural killer cells in systemic lupus erythematosus

Background: The characterisation of the peripheral immune system in the autoimmune disease systemic lupus erythematosus (SLE) at the single-cell level has been limited by the reduced sensitivity of current whole-transcriptomic technologies. Here we employ a targeted single-cell multi-omics approach, combining protein and mRNA quantification, to generate a high-resolution map of the T lymphocyte and natural killer (NK) cell populations in blood from SLE patients. Methods: We designed a custom panel to quantify the transcription of 534 genes in parallel with the expression of 51 surface protein targets using the BD Rhapsody AbSeq single-cell system. We applied this technology to profile 20,656 T and NK cells isolated from peripheral blood from an SLE patient with a type I interferon (IFN)-induced gene expression signature (IFNhi), and an age- and sex- matched IFNlow SLE patient and healthy donor. Results: We confirmed the presence of a rare cytotoxic CD4+ T cell (CTL) subset, which was exclusively present in the IFNhi patient. Furthermore, we identified additional alterations consistent with increased immune activation in this patient, most notably a shift towards terminally differentiated CD57+ CD8+ T cell and CD16+ NKdim phenotypes, and the presence of a subset of recently-activated naïve CD4+ T cells. Conclusions: Our results identify IFN-driven changes in the composition and phenotype of T and NK cells that are consistent with a systemic immune activation within the IFNhi patient, and underscore the added resolving power of this multi-omics approach to identify rare immune subsets. Consequently, we were able to find evidence for novel cellular peripheral biomarkers of SLE disease activity, including a subpopulation of CD57+ CD4+ CTLs.

Exercise end-tidal carbon dioxide pressure: a new prognostic marker after acute myocardial infarction?

Funding Acknowledgements

Type of funding sources: None.

Background

Although several cardiopulmonary exercise testing (CPET) parameters have already proved to predict prognosis, there is increasing interest in finding variables that do not require maximal effort. End-tidal carbon dioxide pressure (PETCO2), an indirect indicator of cardiac output, is one of such variables. Studies in heart failure populations already suggest its role as a prognostic factor. However, data concerning other populations are still scarce.

Purpose

To assess the association between exercise PETCO2, cardiac biomarkers and systolic function following acute myocardial infarction (AMI) and to evaluate its potential prognostic role in this population.

Methods

A retrospective single-centre analysis was conducted including patients who underwent symptom-limited CPET early after AMI. We assessed PETCO2 at baseline (PETCO2-B), at anaerobic threshold (PETCO2-AT) and at peak exercise and calculated the difference between PETCO2-AT and PETCO2-B (PETCO2-difference). We analysed their association with B-natriuretic peptide (BNP), maximal troponin after AMI as well as with left ventricular ejection fraction (LVEF) 1 year after.

Results

We included 40 patients with a mean age of 56 years (87.5% male), assessed with CPET a median of 3 months after AMI (80% of which were ST-elevation myocardial infarctions). Average respiratory exchange ratio was 1,1 with 48% of patients not reaching maximal effort. Mean PETCO2-AT was 37mmHg, with a mean increase from baseline of 6mmHg (PETCO2-difference). There was a significant positive correlation between all the PETCO2 variables measured and BNP values at time of AMI and on follow-up (best correlation for PETCO2-AT with BNP at AMI hospitalization, r = 0.608, p &lt; 0.001). Maximal troponin was not correlated with PETCO2. Both PETCO2-AT and PETCO2-difference were significantly and positively correlated with LVEF 1-year post-AMI (r = 0.421, p = 0.040 and r = 0.511, p = 0.011, respectively).

Conclusion

PETCO2-AT and PETCO2-difference are both correlated with BNP, an established prognostic marker, and with medium-term systolic function after AMI, suggesting their potential prognostic role in this population. Further studies with larger samples are required to confirm the results of this pilot study and assess PETCO2 as a definite predictor of prognosis after AMI.

Left ventricular remodelling patterns after MitraClip implantation: Do ischemic patients have the same benefit?

Funding Acknowledgements

Type of funding sources: None.

Introduction

 Percutaneous mitral valve repair has shown to prevent and even reverse adverse LV remodelling in most patients with moderate to severe mitral regurgitation (MR). This effect is, however, highly variable and may differ according to the MR etiology.

Objectives

 The aim of the present study is to evaluate cardiac remodelling patterns and clinical outcomes after MitraClip implantation (MI) in ischemic and non-ischemic patients (P).

Methods

 A standardized registry was prospectively performed between 2013 and 2019 for all P who underwent MitraClip insertion in a single terciary care centre. Transthoracic echocardiographic information was assessed at baseline and 1, 6, 12 and 18 months after MI. Student’s t-test was used to assess the procedure’s effect on several variables. Clinical outcomes were compared with the use of Fisher’s exact test or the chi-square test, as appropriate.

Results

 46 P, 61% male, mean age 65 ± 14 years. 39% had ischemic MR. Dyslipidemia was more frequent in ischemic P (52% versus 93%, p= 0.002) as well as history of smoking (32% versus 67%, p= 0.022). Atrial fibrillation was significantly associated with non-ischemic etiology (75% versus 44%, p= 0.036). MI success rate was 87% (proper placement and reduction in MR to grade 2 or less), with an average of 1.5 clips. Considering the 37 P that completed 18 months of follow-up (FU), the echocardiographic parameters at baseline were: left ventricular ejection fraction (LVEF) 36 ± 12%, LV end-diastolic dimeter (LVEDD) 68.2 ± 10.2mm, LV end-systolic diameter (LVESD) 52.2 ± 13.5mm and left atrial diameter (LAD) 53.1 ± 6.7mm; there were no significant differences between groups. After MI, a compelling difference in LVEDD was noticeable early in the first month, with significant lower dimensions in non-ischemic P (66.6 ± 11.4 versus 72.8 ± 5.4, p= 0.039). Sustained differences in LVEDD were consistent at 6, 12 and 18 months (62.4 ± 12.3 versus 73.5 ± 7.4, p= 0.025). There was also a reduction in LVESD that became apparent in the sixth month (45.5 ± 15.1 versus 55.3 ± 9.8mm, p= 0.047) and that was sustained after 18 months from MI (45.4 ± 11.7 versus 58.3± 8.9, p= 0.012). No significant differences in LVEF or LAD were noticed over time. Regarding clinical outcomes at 18 months, overall mortality (M) was 24% (9P) and 51% (19P) died or were hospitalized due to heart failure (MH).  No difference was found between groups: M (p= 0.119), MH (p= 0.091).

Conclusion

 This study reports better LV reshape effects after MI in P with non-ischemic etiology, with sustained improvement over time. However, no differences regarding mortality or hospitalization due to HF were apparent at the 18-month FU. Larger long-term studies are required to evaluate these results.

Abstract Figure. LV remodelling pattern

Intersectoral collaboration to promote child development: mapping the relationships

Integrated and intersectoral interventions early in life have the greatest potential to address social inequities, ensuring better opportunities for access to child development support services. The “Projeto Nascente” (Universidade Federal de Minas Gerais and Ministry of Health, Brazil) sought to qualify health and other sectors professionals in actions to promote and monitor early child development, in primary health care. One of its focuses was to stimulate the intersectoral actions to promote child development. The research analyzed the intersectoral network in 31 municipalities in the State of Minas Gerais, Brazil, participating in the 'Projeto Nascente'.

A case study with a qualitative approach was developed using document research on the professionals' perception regarding intersectoral networking. The material was ecomaps elaborated by professionals during the training of the “Projeto Nascente”. The ecomaps represented the local intersectoral networks.

Initially, 29 ecomaps from eleven municipalities were analyzed. Social Protection, Education, Sports, Culture, churches and non-governmental organizations were cited. Other health services were also included. All ecomaps were represented with the family health team in a central position with the other services around them. In municipalities with more than one ecomap, there was no uniformity neither in the services nor in the quality of the relationships represented.

A closer relationship between Education and Social Protection was noticed. However, the quality of the relationships often seemed stressful. Health professionals reported that they invest more energy in relationships than other sectors. Sport and Culture, although less mentioned, seem to be potential partners for new collaborations. The emergence of other health services seems to reflect the fragmentation of the health sector, as well as evidence of the conceptual confusion surrounding intersectoral collaboration.

Key messages

The identification and mapping of the services networking aimed at promoting child development are essential steps in the process of stimulating and reflecting on intersectoral collaboration. The centrality and self-perceived protagonism of the health professionals may not be the best way to involve and count on the participation of other sectors in intersectoral collaboration.

CD70 expression determines the therapeutic efficacy of expanded human regulatory T cells

Regulatory T cells (Tregs) are critical mediators of immune homeostasis. The co-stimulatory molecule CD27 is a marker of highly suppressive Tregs, although the role of the CD27-CD70 receptor-ligand interaction in Tregs is not clear. Here we show that after prolonged in vitro stimulation, a significant proportion of human Tregs gain stable CD70 expression while losing CD27. The expression of CD70 in expanded Tregs is associated with a profound loss of regulatory function and an unusual ability to provide CD70-directed co-stimulation to TCR-activated conventional T cells. Genetic deletion of CD70 or its blockade prevents Tregs from delivering this co-stimulatory signal, thus maintaining their regulatory activity. High resolution targeted single-cell RNA sequencing of human peripheral blood confirms the presence of CD27-CD70+ Treg cells. These findings have important implications for Treg-based clinical studies where cells are expanded over extended periods in order to achieve sufficient treatment doses.

Discovery of CD80 and CD86 as recent activation markers on regulatory T cells by protein-RNA single-cell analysis

BACKGROUND

Traditionally, the transcriptomic and proteomic characterisation of CD4+ T cells at the single-cell level has been performed by two largely exclusive types of technologies: single-cell RNA sequencing (scRNA-seq) and antibody-based cytometry. Here, we present a multi-omics approach allowing the simultaneous targeted quantification of mRNA and protein expression in single cells and investigate its performance to dissect the heterogeneity of human immune cell populations.

METHODS

We have quantified the single-cell expression of 397 genes at the mRNA level and up to 68 proteins using oligo-conjugated antibodies (AbSeq) in 43,656 primary CD4+ T cells isolated from the blood and 31,907 CD45+ cells isolated from the blood and matched duodenal biopsies. We explored the sensitivity of this targeted scRNA-seq approach to dissect the heterogeneity of human immune cell populations and identify trajectories of functional T cell differentiation.

RESULTS

We provide a high-resolution map of human primary CD4+ T cells and identify precise trajectories of Th1, Th17 and regulatory T cell (Treg) differentiation in the blood and tissue. The sensitivity provided by this multi-omics approach identified the expression of the B7 molecules CD80 and CD86 on the surface of CD4+ Tregs, and we further demonstrated that B7 expression has the potential to identify recently activated T cells in circulation. Moreover, we identified a rare subset of CCR9+ T cells in the blood with tissue-homing properties and expression of several immune checkpoint molecules, suggestive of a regulatory function.

CONCLUSIONS

The transcriptomic and proteomic hybrid technology described in this study provides a cost-effective solution to dissect the heterogeneity of immune cell populations at extremely high resolution. Unexpectedly, CD80 and CD86, normally expressed on antigen-presenting cells, were detected on a subset of activated Tregs, indicating a role for these co-stimulatory molecules in regulating the dynamics of CD4+ T cell responses.

P1377Substrate-based ablation in patients with frequent appropriate ICD therapy and dilated cardiomyopathy: long-term experience with high-density mapping

Recurrent ventricular tachydisrhythmias (VT) episodes have a negative impact in the outcome of patients (P) already with an implantable cardioverter-defibrillator (ICD). Elimination of arrhythmic reentry circuits represents a difficult challenge, mainly due to the induction of intolerable VTs, with multiple ECG morphologies, requiring rapid interruption. Substrate guided ablation has been used as a promising approach strategy to treat recurrent VTs. Aim: to assess long-term results of a VT substrate-based ablation using high-density mapping in P with an ICD, severe left ventricular (LV)  dysfunction and recurrent appropriate ICD therapy. Methods: 16P (12 men, non-ischemic cardiomyopathy 67%, 55 ± 13 years, LV ejection fraction 32 ± 6%) and recurrent appropriate shocks despite antiarrhythmic drug therapy and optimal heart failure medication. All P underwent a protocol of ventricular programmed stimulation (600 ms/S3) to obtain baseline VT documentation. A sinus rhythm (SR) voltage map was created using a 3D electroanatomic mapping system (CARTO) with a high-density mapping catheter (PentaRay) to delineate areas of scarred myocardium (ventricular bipolar voltage ≤0,5 mV – dense scar; 0,5-1,5 mV – border zone; ≥1,5 mV – healthy tissue) and provide high-resolution electrophysiological mapping. The substrate modification included catheter elimination of local abnormal ventricular activities (LAVA) - fractionated, splited, low-amplitude/long-lasting, late potentials, pre-systolic potentials - and linear ablation to obtain scars homogenization and scar dechanneling. Pace-mapping techniques were used when capture was possible. LV approach was retrograde in 6 cases, transeptal in 4 and endo-epicardial in 2 cases. In 2P the ablation was performed in the right ventricle. Results: VTs were induced and interrupted with bursts or external DC shocks. LAVA were identified and ablated in all P. Eleven P underwent modification of scar areas. The mean duration of the procedure was 153 mn (103-218 mn), with radiofrequency ranging from 18 to 60 mn (mean 33 min), and a mean fluoroscopy time of 16 mn. Non-inducibility was achieved in 75% of the cases. There was 1 pericardial tamponade drained successfully. During a follow-up of 48 ± 18 months, 75% had no VT recurrences, 2P underwent redo ablation, 1P died from stroke. Conclusion: Catheter ablation of VT based on substrate modification guided by high-density mapping is feasible and safe in P with LV dysfunction. This approach may be of clinical relevance, with potential benefits in reducing VT burden.

P1756 Predictors of outcome in mitral valve repair surgery

Background

Surgical mitral valve repair currently remains a good option in both organic or functional mitral valve regurgitation (MVR). However, a significant number of patients (P) have comorbidities that can contribute to adverse outcomes.

Objective

To determine clinical and echocardiographic predictors of adverse outcomes in P submitted to MV repair surgery in our center, notably MVR recurrence and new MV replacement surgery or all-cause mortality.

Methods

Retrospective analysis of 262 P who underwent MV repair surgery between 2008 and 2017, with a mean follow-up of 30 months. P were included with both organic or functional MV regurgitation. P who underwent simultaneous coronary artery bypass grafting (CABG), atrial fibrillation (AF) surgery and tricuspid valve repair were also included. However, P with simultaneous surgical aortic valve replacement or previous endocarditis were excluded and the remaining 204 P were analysed.

We evaluated whether MVR etiology, simultaneous surgery (tricuspid valve repair, AF or CABG), body mass index (BMI), gender, chronic obstructive pulmonary disease (COPD), diabetes mellitus, renal dysfunction (measured by serum creatinine levels), baseline left ventricular ejection fraction (LVEF) and left ventricle end-diastolic diameter (LVED) were predictors of a composite endpoint (follow-up MV replacement surgery or all-cause mortality) and secondary endpoints: MV replacement surgery and all-cause mortality.

Results

204 P who underwent MV repair surgery, 67.2% male, mean age of 62 ± 14 years. 80.4% had organic MVR and 19.6% functional MVR (mostly ischemic – 72.4%). 7P (3.4%) had rheumatic MVR. 16.8% underwent simultaneous CABG, 12.3% tricuspid valve repair and 7.8% AF ablation. 30-day mortality was 0%.

The composite endpoint occurred in 40P (20%) and there was MVR recurrence with follow-up MV replacement surgery in 15P (7.5%) and all-cause mortality in 28P (13.7%).

The authors found that elevated serum creatinine levels (OR 4.66; p = 0.003), COPD (OR 3.00; p = 0.035) and functional etiology (OR 2.22; p = 0.049) were predictors of the composite endpoint.

Both COPD (OR 2.823; p = 0.024) and renal dysfunction (OR 6.901; p = 0.001) were also found to be independent predictors of all-cause mortality.

Simultaneous CABG was a predictor of all-cause mortality (OR 2.82; p = 0.024).

Female gender was a predictor of future MV replacement surgery (13.4% vs 4.7%, p = 0.023).

However, echocardiographic variables (baseline LVEF and LVED) were not found to be significant predictors of adverse outcomes in MV repair surgery. Likewise, simultaneous AF or tricuspid valve surgery, rheumatic/ischemic etiology, high BMI or diabetes were not associated with poorer prognosis.

Conclusion

In P undergoing MV repair surgery, renal dysfunction and COPD were independent predictors of all-cause mortality. Functional etiology and simultaneous CABG surgery were also predictors of adverse outcomes.

Baseline LVEF and LVED were not correlated with prognosis.

P229 Primary cardiac angiosarcoma of the right atrium: a rare entity presenting with an atrial arrhythmia

Introduction

Primary cardiac tumors are rare entities and 75% are benign. Angiosarcoma is the most common malignant primary cardiac tumor.

We report the case of cardiac angiosarcoma presenting with an atrial arrhythmia.

Clinical case

A 39-year-old female patient with no past medical history presented to the emergency department with heart palpitations and atypical chest pain.

Electrocardiogram on admission showed atrial flutter with a heart rate of 153 beats per minute.

Laboratory analysis were performed showing elevated D-dimer levels (2210 ug/L).

A thoracic CT scan was performed, which ruled out pulmonary embolism, but showed multiple pulmonary nodules and a right atrial (RA) mass measuring 48 mm that could correspond to a thrombus or neoplasia.

The patient was admitted in the Cardiology ICU of our hospital and was started on beta-blocker and amiodarone with conversion to sinus rhythm. Additional exams were performed:

- Transthoracic echocardiogram (TTE) revealed an heterogenous 32,6 x 17,7 mm mass in the lateral wall of the RA with an adherent mobile mass near the tricuspid valve with 28 mm diameter (possible adherent thrombus).

- Cardiac magnetic resonance imaging confirmed a RA tumor with invasion of the atrial free wall and compression of the superior vena cava.

Due to the unclear etiology of the RA mass, ultrasound-guided intracardiac biopsy was performed. Pathological examination revealed spindle cell proliferation, consistent with the diagnosis of angiosarcoma. Immunohistochemical staining was positive for Vimentin, CD34 and CD31, with 70% Ki67 expression.

Later on, the patient developed melena with significant drop of hemoglobin levels, requiring daily red blood cell transfusions and anticoagulation had to be stopped.

The patient was transferred to the Internal Medicine ward and thoracic-abdomen-pelvis staging computed tomography (CT) scan showed a significant increase in the number of pulmonary nodules, bilateral ovarian masses, 4 hepatic nodules and ileum metastization.

During hospitalization, the patient developed right leg deep venous thrombosis and thoracic CT scan revealed bilateral pulmonary embolism.

After improvement of the clinical status, palliative chemotherapy was started and the patient was discharged, maintaining regular outpatient follow-up in the Oncology Department for 1 month.

Cardiac angiosarcoma generally presents in a late stage of the disease with metastatic involvement. When surgical treatment is not possible, despite agressive chemotherapy, the prognosis remains poor.

Abstract P229 Figure. Echocardiogram: right atrium mass

P1330 A rare coronary anomaly in the adult: an extremely large arteriovenous fistula

Introduction

Arteriovenous coronary fistulae are a rare coronary anomaly, which can be congenital or acquired. They can be diagnosed in older adults with heart failure symptoms, atherosclerosis or cardiac arrhythmias.

The authors report the case of an adult patient with an extremely large coronary artery fistula of the left main coronary artery (LMCA).

Clinical case

A 57-year-old caucasian male with known background of arterial hypertension, obesity, pulmonary emphysema and bronchiectasis presented to a Cardiology outpatient appointment with symptoms of congestive heart failure and new-onset atrial fibrillation.

A transthoracic echocardiogram was performed which revealed a possible coronary fistula with multiple rosary-like folds between the LMCA and the coronary sinus. Other echocardiographic findings were left ventricular and biatrial enlargement with biventricular systolic dysfunction (left ventricular ejection fraction 44%) and a GLS of -7.8% as well as mild pericardial effusion.

The patient was referred to our hospital for further diagnostic work-up and clarification of the coronary anatomy.

A cardiac computed tomography (CT) scan was done which showed ectasia and calcification of the LMCA, left anterior descending and circumflex arteries and a large caliber tortuous coronary fistula between the LMCA, the right atrium and the coronary sinus comprised of multiple folds covering from the pulmonary artery to the left atrium.

A coronary artery angiography was also performed, which confirmed the detailed anatomy and dimensions of the coronary fistula.

Follow-up magnetic resonance imaging revealed dilation of both left and right cardiac chambers with no significant shunt (QP/QS = 1)

The patient was started on heart failure medical therapy and was referred to the Cardiac Surgery Department and is currently asymptomatic awaiting for surgical correction of the coronary fistula.

Abstract P1330 Figure. CT scan: large caliber coronary fistula

P1755 Clinical and echocardiographic outcomes of mitral valve repair surgery

Background

Mitral valve regurgitation (MVR) represents the second most frequent valvular heart disease. MV surgical repair is often the preferred treatment when MV anatomy is suitable.

Purpose

To characterize the population who underwent MV repair surgery and evaluate the outcomes of residual MVR, allcause mortality and functional classification.

Methods

Retrospective analysis of 262 patients (P) admitted between 2008 and 2017 for MV repair surgery. P who undergone simultaneous coronary artery bypass graft (CABG) surgery, atrial fibrillation (AF) surgery and tricuspid valve repair were also included. P with endocarditis, P who underwent simultaneous aortic valve replacement and P with rheumatic predominant MV stenosis were excluded, the remaining 204 P were analysed. Clinical and echocardiographic characteristics were evaluated in a mean follow-up of 30 months.

Results

204 P, 67.2% male, mean age 62 + 14 years. The most frequent etiology was organic (80.4%), mostly of degenerative cause. Functional etiology was present in 19.6%, mostly ischemic (72.4%). 16.8% underwent simultaneous CABG, 12.3% tricuspid valve repair and 7.8% AF ablation.

Hypertension was significantly associated with functional etiology (90% vs 72.8%, p = 0.022), as well as hypercholesterolemia (80% vs 48.2%, p &lt; 0.001) and diabetes mellitus (32.5% vs 10.4%, p &lt; 0.001). Baseline left ventricular ejection fraction (LVEF) was &gt;50% in 78.4%, reduced (30-50%) 18.1% and poor (&lt;30%) in 3.4%.

Functional etiology was significantly associated with LVEF &lt;50% (70% vs 9.1%, p &lt; 0.001).

161P (78.9%) had MV prolapse: 120P (74.5%) posterior, 29P (18%) anterior and 7.4% (12P) of both leaflets. P2 was the most frequently involved scallop, in 92P (57.1%), followed by P3, in 41P (25.4%). There was MV chordae rupture in 94P (58.3%).

Post-surgery echocardiography revealed that 93.8% had mild or no residual MVR.

30-day mortality rate was 0%.

There was MVR recurrence with MV replacement surgery in 15P (7.5%), mean time 37.1 months. All-cause mortality was registered in 28P (13.7%), with a mean time of 43.7 months after MV surgery.

Of the P without MVR recurrence or mortality, 111P (70%) were in NYHA class I, 41P (26%) in NYHA class II and 6P (4%) in NYHA class III. 6P were lost to follow-up. Upon echocardiographic revaluation there was no residual MVR in 53P (39%), mild MVR in 67P (49%) and moderate MVR in 16P (11.8%).

Conclusion

In P who underwent MV repair surgery, there was 7.5% recurrence rate with follow-up MV replacement surgery and an all-cause mortality of 13.7%. In a mean follow-up of 30 months, 70% of P were in NYHA I class and there was none or mild residual MVR in 88% of P.

1113 Primary and secondary malignant cardiac tumors - a 22 year case review

Background

Primary cardiac tumors are extremely rare and are usually diagnosed late due to the non-specific symptomatology. Surgery is the main treatment option and despite chemotherapy, the prognosis remains poor. Cardiac invasion by metastatic tumors, while more common, also entails an unsatisfactory outcome.

Purpose

To review patients (P) with malignant cardiac tumours that were diagnosed by transthoracic echocardiography (TTE) or by transesophageal echocardiogram (TEE) in a tertiary center between 1997 and 2019.

Methods

Retrospective analysis of clinical data from the digital files, echocardiographic assessment of tumor location and morphology, histology results and survival outcomes.

Results

A total of 33 malignant cardiac tumors were diagnosed: 12 primary tumors (A) and 21 metastatic tumors (B).

A

Regarding primary cardiac tumors, the most common types were angiosarcomas (6 cases), 2 undifferentiated pleomorphic sarcomas, 1 right ventricle (RV) sarcoma, 1 primary cardiac lymphoma, 1 myxofibrosarcoma and 1 fibrosarcoma.

The mean age of the P at time of diagnosis was 43 ± 15 years, 50% female gender. The most frequent presentation was heart failure symptoms (50% of P) followed by arrhythmias (20%). One patient had a rare presentation with pruritus and polyarthralgias.

On TTE, the most prevalent tumor location was in the right-heart chambers (70%) - mostly the right atrium (50%), with mean dimensions of 40 ± 18 mm x 27 ± 11 mm.

85% of patients had preserved systolic left ventricular function and there was moderate or severe pericardial effusion in 38%.

The most frequent distant metastatic involvement of primary tumors at diagnosis was pulmonary (33%) and hepatic (33%).

50% of P were submitted to tumor resection and 40% were submitted to chemotherapy.

In the case of angiosarcomas, the most common immunohistochemical markers were vimentin, CD31 and CD34.

The authors found a mortality rate of 81% in P with primary cardiac tumors, with a median time of follow-up of 6 months (minimum of 20 days and maximum of 18 years). In the latter case, the P was submitted to heart transplantation after diagnosis of a sarcoma of the RV and is still alive and well.

B

Regarding secondary cardiac invasion, there was a diagnosis of the following primary tumor sites: 6 thymomas, 4 cases of lymphoma, 3 lung carcinomas, 3 hepatocellular carcinomas, 2 bladder carcinomas, 1 parathyroid carcinoma, 1 soft tissue sarcoma and 1 melanoma.

The mean age of P with metastastic involvement of the heart was 57 ± 22 years, 65% male. On TTE/TEE the authors also found a right-sided chambers predominance (60%), with pericardial metastasis in 35%.

As expected, the mortality rate was also extremely high (90%), with a median time of follow up of 1.5 months (minimum of one week, maximum of 44 months)

Conclusion

Cardiac malignant tumors generally present in a late stage with a dismal prognosis. When possible, heart transplantation can be an option with a good outcome.

Chronic Immune Activation in Systemic Lupus Erythematosus and the Autoimmune PTPN22 Trp620 Risk Allele Drive the Expansion of FOXP3+ Regulatory T Cells and PD-1 Expression

In systemic lupus erythematosus (SLE), perturbed immunoregulation underpins a pathogenic imbalance between regulatory and effector CD4⁺ T-cell activity. However, to date, the characterization of the CD4⁺ regulatory T cell (Treg) compartment in SLE has yielded conflicting results. Here we show that patients have an increased frequency of CD4⁺FOXP3⁺ cells in circulation owing to a specific expansion of thymically-derived FOXP3⁺HELIOS⁺ Tregs with a demethylated FOXP3 Treg-specific demethylated region. We found that the Treg expansion was strongly associated with markers of recent immune activation, including PD-1, plasma concentrations of IL-2 and the type I interferon biomarker soluble SIGLEC-1. Since the expression of the negative T-cell signaling molecule PTPN22 is increased and a marker of poor prognosis in SLE, we tested the influence of its missense risk allele Trp⁶²⁰ (rs2476601C>T) on Treg frequency. Trp⁶²⁰ was reproducibly associated with increased frequencies of thymically-derived Tregs in blood, and increased PD-1 expression on both Tregs and effector T cells (Teffs). Our results support the hypothesis that FOXP3⁺ Tregs are increased in SLE patients as a consequence of a compensatory mechanism in an attempt to regulate pathogenic autoreactive Teff activity. We suggest that restoration of IL-2-mediated homeostatic regulation of FOXP3⁺ Tregs by IL-2 administration could prevent disease flares rather than treating at the height of a disease flare. Moreover, stimulation of PD-1 with specific agonists, perhaps in combination with low-dose IL-2, could be an effective therapeutic strategy in autoimmune disease and in other immune disorders.

P5243Indirect costs of acute myocardial infarction in Portugal

Introduction

Cardiovascular diseases are the main cause of death in Portugal. The high incidence of acute myocardial infarction (AMI) is also a major problem, particularly due to the economic burden caused by productivity losses (indirect costs) associated with temporary absence from work, not yet sufficiently studied in Portugal. Our objective was to quantify the indirect costs of AMI in the first year after admission.

Methods

All consecutive patients admitted in a single center with <66 years (official retirement age) during one year that survived to discharge were included in the present study. Employment status on admission was assessed in every patient. For each employed patient, working at the time of admission, the monthly wage was estimated from market wage rates from national public sources (grossed up by social security contributions) according to gender and age. A day-cost was calculated to assess the cost of temporary absence from work. A half-day absence was considered for Cardiology medical appointments and exams. The duration of temporary absence from work was assessed by a first follow-up contact at 30-day and a second follow-up evaluation up to one-year after admission. The cost of temporary absence from work per episode was calculated in this sample and results were applied to the total number of MI in Portugal during the year 2016 (last available national data) and separately according to ST-elevation AMI (STEAMI) or non-ST-elevation acute coronary syndrome (NSTACS).

Results

We included 219 patients (54±7 years, 83% males), from which, 66.2% were working, 16.4% early-retired, 11.9% unemployed and 5.5% in long-term exit from work due to non-cardiac disease. During the one-year follow-up there were no changes in employment status. In our sample, mean monthly labor cost was 1802 euros (69 euros/day). Median number of days absent from work were 34 days (31 days in men and 52 days in women) and a median of 2 half-days were also obtained for Cardiology appointments / exams. We obtained a total cost of 760.521,55 euros. We used available data from 2016 to estimate indirect costs at a national level. There were 4133 patients with <66 years admitted in Portugal due to AMI that survived to discharge. We performed an analysis, using the proportions of 41% of cases with STEAMI and 59% with NSTACS that came out of the Portuguese Registry on Acute Coronary Syndromes and the working patient's proportions in each group. Costs were higher in patients with STEAMI. We estimate an indirect total cost in Portugal of € 10.12 million in the first year after MI.

Conclusions

In Portugal, the costs to society of disability generated losses of productivity are over ten million euros during the first year after AMI. Strategies to improve time of return to work are very important to lower these costs.

P3628Contemporary coronary artery disease prevalence in a valvular heart disease population undergoing surgery

Background

Patients undergoing heart valve surgery are routinely evaluated for the presence of Coronary Artery Disease (CAD), with the standard practice of combining valve intervention with a revascularization procedure, notably Coronary Artery Bypass Graft (CABG). Older studies suggest rates as high as 50% prevalence of CAD in this population. However, CAD prevalence, its treatment and prognostic implication has been questioned recently.

Objectives

The goal of this study is to evaluate the baseline characteristics, prevalence of CAD and treatment strategies in a contemporary population with valvular heart disease (VHD) referred for valve surgery.

Methods

In a national multicentre registry, consecutive patients, from Jan 2015 to Dec 2016, with a formal indication for heart valve surgery referred for a pre-op routine coronary angiogram were systematically analysed. Baseline characteristics, valve pathology and CAD prevalence and patterns were determined. Obstructive CAD was defined as luminal angiographic stenosis ≥70% (≥50% for left main artery). The prognostic impact of the different valve disease and CAD treatment strategies were assessed.

Results

1175 patients (mean age 72.5±10.1; male 49.2%) fulfilled the clinical or echocardiographic indication for valve surgery by European guidelines. Valvular disease prevalence was: aortic stenosis (66.7%), aortic regurgitation (6.6%), mitral stenosis (6%), mitral regurgitation (19.2%), tricuspid regurgitation (7.5%). Mean follow-up time was 29.06±18.46 months. Prevalence of comorbidities was: Diabetes Mellitus (DM) 26%, chronic obstructive pulmonary disease (COPD) 5.7% and chronic kidney disease (CKD) 23.4%. Mean Euroscore II was 2.6%. Obstructive CAD was present in 27.3% patients. Mean Syntax score was 10.2 (<22 in 88%, 23–32 in 10.2% and >33 in 1.8%). Left main artery and 3-vessel disease were found in 13.1% and 11.8% of patients with CAD, respectively. Valvular surgery was ultimately performed in 80.3%. In patients with CAD, 57.3% were revascularized. All-cause mortality rate during follow-up was 12.9%, with 7.8% from cardiovascular causes. In univariate analysis DM, COPD, CKD, NYHA class, obstructive CAD and no surgery (p<0.05) were associate with mortality on follow up. In multivariate analysis obstructive CAD (OR 2.36, 95% CI 1.53–3.65, p<0.01) and no surgery (OR 6.05, 95% CI 3.95–9.30, p<0.01) persisted as independent all-cause mortality predictors.

Conclusion

In a contemporary cohort of patients with VHD and surgical indication, CAD prevalence is lower (27.3%) than described in literature. Mortality rates were higher in patients with obstructive CAD, worse NYHA functional class and in those who never underwent surgery.

Oral antioxidant therapy for prevention and treatment of preeclampsia: Meta-analysis of randomized controlled trials

AIMS

To determine whether oral antioxidant therapies, of various types and doses, are able to prevent or treat women with preeclampsia.

DATA SYNTHESIS

The following databases were searched: MEDLINE, CENTRAL, LILACS, and Web of Science. Inclusion criteria were: a) randomized clinical trials; b) oral antioxidant supplementation; c) study in pregnant women; d) control group, treated or not with placebo. Papers were excluded if they evaluated antioxidant nutrient supplementation associated with other non-antioxidant therapies. Data were extracted and the risk of bias of each study was assessed. Heterogeneity was analyzed using the Cochran Q test, and I2 statistics and pre-specified sensitivity analyses were performed. Meta-analyses were conducted on prevention and treatment studies, separately. The primary outcome was the incidence of preeclampsia in prevention trials, and of perinatal death in treatment trials. Twenty-nine studies were included in the analysis, 19 for prevention and 10 for treatment. The antioxidants used in these studies were vitamins C and E, selenium, l-arginine, allicin, lycopene and coenzyme Q10, none of which showed beneficial effects on the prevention of preeclampsia (RR: 0.89, CI 95%: [0.79-1.02], P = 0.09; I² = 39%, P = 0.04) and other outcomes. The antioxidants used in the treatment studies were vitamins C and E, N-acetylcysteine, l-arginine, and resveratrol. A beneficial effect was found in intrauterine growth restriction.

CONCLUSIONS

Antioxidant therapy had no effects in the prevention of preeclampsia but did show beneficial effects in intrauterine growth restriction, when used in the treatment of this condition.

The plasma biomarker soluble SIGLEC-1 is associated with the type I interferon transcriptional signature, ethnic background and renal disease in systemic lupus erythematosus

Background

The molecular heterogeneity of autoimmune and inflammatory diseases has been one of the main obstacles to the development of safe and specific therapeutic options. Here, we evaluated the diagnostic and clinical value of a robust, inexpensive, immunoassay detecting the circulating soluble form of the monocyte-specific surface receptor sialic acid binding Ig-like lectin 1 (sSIGLEC-1).

Methods

We developed an immunoassay to measure sSIGLEC-1 in small volumes of plasma/serum from systemic lupus erythematosus (SLE) patients (n = 75) and healthy donors (n = 504). Samples from systemic sclerosis patients (n = 99) were studied as an autoimmune control. We investigated the correlation between sSIGLEC-1 and both monocyte surface SIGLEC-1 and type I interferon-regulated gene (IRG) expression. Associations of sSIGLEC-1 with clinical features were evaluated in an independent cohort of SLE patients (n = 656).

Results

Plasma concentrations of sSIGLEC-1 strongly correlated with expression of SIGLEC-1 on the surface of blood monocytes and with IRG expression in SLE patients. We found ancestry-related differences in sSIGLEC-1 concentrations in SLE patients, with patients of non-European ancestry showing higher levels compared to patients of European ancestry. Higher sSIGLEC-1 concentrations were associated with lower serum complement component 3 and increased frequency of renal complications in European patients, but not with the SLE Disease Activity Index clinical score.

Conclusions

Our sSIGLEC-1 immunoassay provides a specific and easily assayed marker for monocyte–macrophage activation, and interferonopathy in SLE and other diseases. Further studies can extend its clinical associations and its potential use to stratify patients and as a secondary endpoint in clinical trials.

Electronic supplementary material

The online version of this article (10.1186/s13075-018-1649-1) contains supplementary material, which is available to authorized users.

Capturing the systemic immune signature of a norovirus infection: an n-of-1 case study within a clinical trial

Background: The infection of a participant with norovirus during the adaptive study of interleukin-2 dose on regulatory T cells in type 1 diabetes (DILT1D) allowed a detailed insight into the cellular and cytokine immune responses to this prevalent gastrointestinal pathogen.

Methods:  Serial blood, serum and peripheral blood mononuclear cell (PBMC) samples were collected pre-, and post-development of the infection. To differentiate between the immune response to norovirus and to control for the administration of a single dose of aldesleukin (recombinant interleukin-2, rIL-2) alone, samples from five non-infected participants administered similar doses were analysed in parallel.

Results: Norovirus infection was self-limited and resolved within 24 hours, with the subsequent development of anti-norovirus antibodies. Serum pro- and anti-inflammatory cytokine levels, including IL-10, peaked during the symptomatic period of infection, coincident with increased frequencies of monocytes and neutrophils. At the same time, the frequency of regulatory CD4 ⁺ T cell (Treg), effector T cell (Teff) CD4 ⁺ and CD8 ⁺ subsets were dynamically reduced, rebounding to baseline levels or above at the next sampling point 24 hours later.  NK cells and NKT cells transiently increased CD69 expression and classical monocytes expressed increased levels of CD40, HLA-DR and SIGLEC-1, biomarkers of an interferon response. We also observed activation and mobilisation of Teffs, where increased frequencies of CD69 ⁺ and Ki-67 ⁺ effector memory Teffs were followed by the emergence of memory CD8 ⁺ Teff expressing the mucosal tissue homing markers CD103 and β7 integrin. Treg responses were coincident with the innate cell, Teff and cytokine response. Key Treg molecules FOXP3, CTLA-4, and CD25 were upregulated following infection, alongside an increase in frequency of Tregs with the capacity to home to tissues.

Conclusions:  The results illustrate the innate, adaptive and counter-regulatory immune responses to norovirus infection. Low-dose IL-2 administration induces many of the Treg responses observed during infection.

Chromosome contacts in activated T cells identify autoimmune disease candidate genes

Background

Autoimmune disease-associated variants are preferentially found in regulatory regions in immune cells, particularly CD4⁺ T cells. Linking such regulatory regions to gene promoters in disease-relevant cell contexts facilitates identification of candidate disease genes.

Results

Within 4 h, activation of CD4⁺ T cells invokes changes in histone modifications and enhancer RNA transcription that correspond to altered expression of the interacting genes identified by promoter capture Hi-C. By integrating promoter capture Hi-C data with genetic associations for five autoimmune diseases, we prioritised 245 candidate genes with a median distance from peak signal to prioritised gene of 153 kb. Just under half (108/245) prioritised genes related to activation-sensitive interactions. This included IL2RA, where allele-specific expression analyses were consistent with its interaction-mediated regulation, illustrating the utility of the approach.

Conclusions

Our systematic experimental framework offers an alternative approach to candidate causal gene identification for variants with cell state-specific functional effects, with achievable sample sizes.

Electronic supplementary material

The online version of this article (doi:10.1186/s13059-017-1285-0) contains supplementary material, which is available to authorized users.

Capturing the systemic immune signature of a norovirus infection: an n-of-1 case study within a clinical trial

BACKGROUND

The infection of a participant with norovirus during the adaptive study of interleukin-2 dose on regulatory T cells in type 1 diabetes (DILT1D) allowed a detailed insight into the cellular and cytokine immune responses to this prevalent gastrointestinal pathogen.

METHODS

Serial blood, serum and peripheral blood mononuclear cell (PBMC) samples were collected pre-, and post-development of the infection. To differentiate between the immune response to norovirus and to control for the administration of a single dose of aldesleukin (recombinant interleukin-2, rIL-2) alone, samples from five non-infected participants administered similar doses were analysed in parallel.

RESULTS

Norovirus infection was self-limited and resolved within 24 hours, with the subsequent development of anti-norovirus antibodies. Serum pro- and anti-inflammatory cytokine levels, including IL-10, peaked during the symptomatic period of infection, coincident with increased frequencies of monocytes and neutrophils. At the same time, the frequency of regulatory CD4 ⁺ T cell (Treg), effector T cell (Teff) CD4 ⁺ and CD8 ⁺ subsets were dynamically reduced, rebounding to baseline levels or above at the next sampling point 24 hours later.  NK cells and NKT cells transiently increased CD69 expression and classical monocytes expressed increased levels of CD40, HLA-DR and SIGLEC-1, biomarkers of an interferon response. We also observed activation and mobilisation of Teffs, where increased frequencies of CD69 ⁺ and Ki-67 ⁺ effector memory Teffs were followed by the emergence of memory CD8 ⁺ Teff expressing the mucosal tissue homing markers CD103 and β7 integrin. Treg responses were coincident with the innate cell, Teff and cytokine response. Key Treg molecules FOXP3, CTLA-4, and CD25 were upregulated following infection, alongside an increase in frequency of Tregs with the capacity to home to tissues.

CONCLUSIONS

The results illustrate the innate, adaptive and counter-regulatory immune responses to norovirus infection. Low-dose IL-2 administration induces many of the Treg responses observed during infection.

Neonatal and adult recent thymic emigrants produce IL-8 and express complement receptors CR1 and CR2

The maintenance of peripheral naive T lymphocytes in humans is dependent on their homeostatic division, not continuing emigration from the thymus, which undergoes involution with age. However, postthymic maintenance of naive T cells is still poorly understood. Previously we reported that recent thymic emigrants (RTEs) are contained in CD31⁺CD25⁻ naive T cells as defined by their levels of signal joint T cell receptor rearrangement excision circles (sjTRECs). Here, by differential gene expression analysis followed by protein expression and functional studies, we define that the naive T cells having divided the least since thymic emigration express complement receptors (CR1 and CR2) known to bind complement C3b- and C3d-decorated microbial products and, following activation, produce IL-8 (CXCL8), a major chemoattractant for neutrophils in bacterial defense. We also observed an IL-8–producing memory T cell subpopulation coexpressing CR1 and CR2 and with a gene expression signature resembling that of RTEs. The functions of CR1 and CR2 on T cells remain to be determined, but we note that CR2 is the receptor for Epstein-Barr virus, which is a cause of T cell lymphomas and a candidate environmental factor in autoimmune disease.

Complement receptors (CR1 and CR2) and IL-8 production identify T cells that have recently left the thymus.

Cells with Treg-specific FOXP3 demethylation but low CD25 are prevalent in autoimmunity

Identification of alterations in the cellular composition of the human immune system is key to understanding the autoimmune process. Recently, a subset of FOXP3⁺ cells with low CD25 expression was found to be increased in peripheral blood from systemic lupus erythematosus (SLE) patients, although its functional significance remains controversial. Here we find in comparisons with healthy donors that the frequency of FOXP3⁺ cells within CD127^lowCD25^low CD4⁺ T cells (here defined as CD25^lowFOXP3⁺ T cells) is increased in patients affected by autoimmune disease of varying severity, from combined immunodeficiency with active autoimmunity, SLE to type 1 diabetes. We show that CD25^lowFOXP3⁺ T cells share phenotypic features resembling conventional CD127^lowCD25^highFOXP3⁺ Tregs, including demethylation of the Treg-specific epigenetic control region in FOXP3, HELIOS expression, and lack of IL-2 production. As compared to conventional Tregs, more CD25^lowFOXP3⁺HELIOS⁺ T cells are in cell cycle (33.0% vs 20.7% Ki-67⁺; P = 1.3 × 10⁻⁹) and express the late-stage inhibitory receptor PD-1 (67.2% vs 35.5%; P = 4.0 × 10⁻¹⁸), while having reduced expression of the early-stage inhibitory receptor CTLA-4, as well as other Treg markers, such as FOXP3 and CD15s. The number of CD25^lowFOXP3⁺ T cells is correlated (P = 3.1 × 10⁻⁷) with the proportion of CD25^highFOXP3⁺ T cells in cell cycle (Ki-67⁺). These findings suggest that CD25^lowFOXP3⁺ T cells represent a subset of Tregs that are derived from CD25^highFOXP3⁺ T cells, and are a peripheral marker of recent Treg expansion in response to an autoimmune reaction in tissues.

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FOXP3⁺ compartment within CD127^lowCD25^low T cells is expanded in autoimmune patients.

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Increased numbers of CD25^lowFOXP3⁺ T cells are a circulating marker of autoimmunity.

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CD25^lowFOXP3⁺ HELIOS⁺ T cells are fully demethylated at the FOXP3 TSDR.

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CD25^lowFOXP3⁺ T cells could represent a terminal differentiation stage of regulatory T cells.

Capturing the systemic immune signature of a norovirus infection: an n-of-1 case study within a clinical trial

Background: The infection of a participant with norovirus during the adaptive study of interleukin-2 dose on regulatory T cells in type 1 diabetes (DILT1D) allowed a detailed insight into the cellular and cytokine immune responses to this prevalent gastrointestinal pathogen. Methods: Serial blood, serum and peripheral blood mononuclear cell (PBMC) samples were collected pre-, and post-development of the infection. To differentiate between the immune response to norovirus and to control for the administration of a single dose of aldesleukin (recombinant interleukin-2, rIL-2) alone, samples from five non-infected participants administered similar doses were analysed in parallel. Results: Norovirus infection was self-limited and resolved within 24 hours, with the subsequent development of anti-norovirus antibodies. Serum pro- and anti-inflammatory cytokine levels, including IL-10, peaked during the symptomatic period of infection, coincident with increased frequencies of monocytes and neutrophils. At the same time, the frequency of regulatory CD4+ T cell (Treg), effector T cell (Teff) CD4+ and CD8+ subsets were dynamically reduced, rebounding to baseline levels or above at the next sampling point 24 hours later.  NK cells and NKT cells transiently increased CD69 expression and classical monocytes expressed increased levels of CD40, HLA-DR and SIGLEC-1, biomarkers of an interferon response. We also observed activation and mobilisation of Teffs, where increased frequencies of CD69+ and Ki-67+ effector memory Teffs were followed by the emergence of memory CD8+ Teff expressing the mucosal tissue homing markers CD103 and β7 integrin. Treg responses were coincident with the innate cell, Teff and cytokine response. Key Treg molecules FOXP3, CTLA-4, and CD25 were upregulated following infection, alongside an increase in frequency of Tregs with the capacity to home to tissues. Conclusions: The results illustrate the innate, adaptive and counter-regulatory immune responses to norovirus infection. Low-dose IL-2 administration induces many of the Treg responses observed during infection.

In-depth immunophenotyping data of IL-6R on the human peripheral regulatory T cell (Treg) compartment

We provide in this paper a detailed characterization of the human peripheral CD4⁺ CD127^lowCD25⁺ regulatory T cell (Treg) compartment, with a particular emphasis in defining the population expressing higher levels of the IL-6 receptor (IL-6R). We provide a description of the phenotype of this population by assessing both the surface expression by flow cytometry as well as their transcriptional profile and functional features. In addition, we also present functional data describing the responsiveness of these subsets to IL-6 signalling in vitro and to IL-2 in vivo. The data presented in this paper support the research article “Human IL-6R^hiTIGIT⁻ CD4⁺CD127^lowCD25⁺ T cells display potent in vitro suppressive capacity and a distinct Th17 profile” (Ferreira RC et al., 2017; doi: 10.1016/j.clim.2017.03.002) [1].

Neutrophil-mediated IL-6 receptor trans-signaling and the risk of chronic obstructive pulmonary disease and asthma

The Asp358Ala variant in the interleukin-6 receptor (IL-6R) gene has been implicated in asthma, autoimmune and cardiovascular disorders, but its role in other respiratory conditions such as chronic obstructive pulmonary disease (COPD) has not been investigated. The aims of this study were to evaluate whether there is an association between Asp358Ala and COPD or asthma risk, and to explore the role of the Asp358Ala variant in sIL-6R shedding from neutrophils and its pro-inflammatory effects in the lung. We undertook logistic regression using data from the UK Biobank and the ECLIPSE COPD cohort. Results were meta-analyzed with summary data from a further three COPD cohorts (7,519 total cases and 35,653 total controls), showing no association between Asp358Ala and COPD (OR = 1.02 [95% CI: 0.96, 1.07]). Data from the UK Biobank showed a positive association between the Asp358Ala variant and atopic asthma (OR = 1.07 [1.01, 1.13]). In a series of in vitro studies using blood samples from 37 participants, we found that shedding of sIL-6R from neutrophils was greater in carriers of the Asp358Ala minor allele than in non-carriers. Human pulmonary artery endothelial cells cultured with serum from homozygous carriers showed an increase in MCP-1 release in carriers of the minor allele, with the difference eliminated upon addition of tocilizumab. In conclusion, there is evidence that neutrophils may be an important source of sIL-6R in the lungs, and the Asp358Ala variant may have pro-inflammatory effects in lung cells. However, we were unable to identify evidence for an association between Asp358Ala and COPD.

Human IL-6RhiTIGIT- CD4+CD127lowCD25+ T cells display potent in vitro suppressive capacity and a distinct Th17 profile

To date many clinical studies aim to increase the number and/or fitness of CD4⁺ CD127^lowCD25⁺ regulatory T cells (Tregs) in vivo to harness their regulatory potential in the context of treating autoimmune disease. Here, we sought to define the phenotype and function of Tregs expressing the highest levels of IL-6 receptor (IL-6R). We have identified a population of CD4⁺ CD127^lowCD25⁺ TIGIT⁻ T cells distinguished by their elevated IL-6R expression that lacked expression of HELIOS, showed higher CTLA-4 expression, and displayed increased suppressive capacity compared to IL-6R^hiTIGIT⁺ Tregs. IL-6R^hiTIGIT⁻ CD127^lowCD25⁺ T cells contained a majority of cells demethylated at FOXP3 and displayed a Th17 transcriptional signature, including RORC (RORγt) and the capacity of producing both pro- and anti-inflammatory cytokines, such as IL-17, IL-22 and IL-10. We propose that in vivo, in the presence of IL-6-associated inflammation, the suppressive function of CD4⁺ CD127^lowCD25⁺ FOXP3⁺ IL-6R^hiTIGIT⁻ T cells is temporarily disarmed allowing further activation of the effector functions and potential pathogenic tissue damage.

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IL-6R is highly expressed in certain Treg subsets.

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IL-6R^hiTIGIT⁻ CD127^lowCD25⁺ T cells contain a subset of antigen-experienced Tregs with potent suppression capacity.

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IL-6R^hiTIGIT⁻ Tregs display a Th17 transcriptional profile ex vivo, and the capacity to migrate to the gut.

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IL-2 treatment in humans elicits the trafficking and expansion of Tregs in circulation.

Regulatory T Cell Responses in Participants with Type 1 Diabetes after a Single Dose of Interleukin-2: A Non-Randomised, Open Label, Adaptive Dose-Finding Trial

BACKGROUND

Interleukin-2 (IL-2) has an essential role in the expansion and function of CD4+ regulatory T cells (Tregs). Tregs reduce tissue damage by limiting the immune response following infection and regulate autoreactive CD4+ effector T cells (Teffs) to prevent autoimmune diseases, such as type 1 diabetes (T1D). Genetic susceptibility to T1D causes alterations in the IL-2 pathway, a finding that supports Tregs as a cellular therapeutic target. Aldesleukin (Proleukin; recombinant human IL-2), which is administered at high doses to activate the immune system in cancer immunotherapy, is now being repositioned to treat inflammatory and autoimmune disorders at lower doses by targeting Tregs.

METHODS AND FINDINGS

To define the aldesleukin dose response for Tregs and to find doses that increase Tregs physiologically for treatment of T1D, a statistical and systematic approach was taken by analysing the pharmacokinetics and pharmacodynamics of single doses of subcutaneous aldesleukin in the Adaptive Study of IL-2 Dose on Regulatory T Cells in Type 1 Diabetes (DILT1D), a single centre, non-randomised, open label, adaptive dose-finding trial with 40 adult participants with recently diagnosed T1D. The primary endpoint was the maximum percentage increase in Tregs (defined as CD3+CD4+CD25highCD127low) from the baseline frequency in each participant measured over the 7 d following treatment. There was an initial learning phase with five pairs of participants, each pair receiving one of five pre-assigned single doses from 0.04 × 106 to 1.5 × 106 IU/m2, in order to model the dose-response curve. Results from each participant were then incorporated into interim statistical modelling to target the two doses most likely to induce 10% and 20% increases in Treg frequencies. Primary analysis of the evaluable population (n = 39) found that the optimal doses of aldesleukin to induce 10% and 20% increases in Tregs were 0.101 × 106 IU/m2 (standard error [SE] = 0.078, 95% CI = -0.052, 0.254) and 0.497 × 106 IU/m2 (SE = 0.092, 95% CI = 0.316, 0.678), respectively. On analysis of secondary outcomes, using a highly sensitive IL-2 assay, the observed plasma concentrations of the drug at 90 min exceeded the hypothetical Treg-specific therapeutic window determined in vitro (0.015-0.24 IU/ml), even at the lowest doses (0.040 × 106 and 0.045 × 106 IU/m2) administered. A rapid decrease in Treg frequency in the circulation was observed at 90 min and at day 1, which was dose dependent (mean decrease 11.6%, SE = 2.3%, range 10.0%-48.2%, n = 37), rebounding at day 2 and increasing to frequencies above baseline over 7 d. Teffs, natural killer cells, and eosinophils also responded, with their frequencies rapidly and dose-dependently decreased in the blood, then returning to, or exceeding, pretreatment levels. Furthermore, there was a dose-dependent down modulation of one of the two signalling subunits of the IL-2 receptor, the β chain (CD122) (mean decrease = 58.0%, SE = 2.8%, range 9.8%-85.5%, n = 33), on Tregs and a reduction in their sensitivity to aldesleukin at 90 min and day 1 and 2 post-treatment. Due to blood volume requirements as well as ethical and practical considerations, the study was limited to adults and to analysis of peripheral blood only.

CONCLUSIONS

The DILT1D trial results, most notably the early altered trafficking and desensitisation of Tregs induced by a single ultra-low dose of aldesleukin that resolves within 2-3 d, inform the design of the next trial to determine a repeat dosing regimen aimed at establishing a steady-state Treg frequency increase of 20%-50%, with the eventual goal of preventing T1D.

TRIAL REGISTRATION

ISRCTN Registry ISRCTN27852285; ClinicalTrials.gov NCT01827735.

Natural Variation in Interleukin-2 Sensitivity Influences Regulatory T-Cell Frequency and Function in Individuals With Long-standing Type 1 Diabetes

Defective immune homeostasis in the balance between FOXP3+ regulatory T cells (Tregs) and effector T cells is a likely contributing factor in the loss of self-tolerance observed in type 1 diabetes (T1D). Given the importance of interleukin-2 (IL-2) signaling in the generation and function of Tregs, observations that polymorphisms in genes in the IL-2 pathway associate with T1D and that some individuals with T1D exhibit reduced IL-2 signaling indicate that impairment of this pathway may play a role in Treg dysfunction and the pathogenesis of T1D. Here, we have examined IL-2 sensitivity in CD4+ T-cell subsets in 70 individuals with long-standing T1D, allowing us to investigate the effect of low IL-2 sensitivity on Treg frequency and function. IL-2 responsiveness, measured by STAT5a phosphorylation, was a very stable phenotype within individuals but exhibited considerable interindividual variation and was influenced by T1D-associated PTPN2 gene polymorphisms. Tregs from individuals with lower IL-2 signaling were reduced in frequency, were less able to maintain expression of FOXP3 under limiting concentrations of IL-2, and displayed reduced suppressor function. These results suggest that reduced IL-2 signaling may be used to identify patients with the highest Treg dysfunction and who may benefit most from IL-2 immunotherapy.

Dissection of a Complex Disease Susceptibility Region Using a Bayesian Stochastic Search Approach to Fine Mapping

Identification of candidate causal variants in regions associated with risk of common diseases is complicated by linkage disequilibrium (LD) and multiple association signals. Nonetheless, accurate maps of these variants are needed, both to fully exploit detailed cell specific chromatin annotation data to highlight disease causal mechanisms and cells, and for design of the functional studies that will ultimately be required to confirm causal mechanisms. We adapted a Bayesian evolutionary stochastic search algorithm to the fine mapping problem, and demonstrated its improved performance over conventional stepwise and regularised regression through simulation studies. We then applied it to fine map the established multiple sclerosis (MS) and type 1 diabetes (T1D) associations in the IL-2RA (CD25) gene region. For T1D, both stepwise and stochastic search approaches identified four T1D association signals, with the major effect tagged by the single nucleotide polymorphism, rs12722496. In contrast, for MS, the stochastic search found two distinct competing models: a single candidate causal variant, tagged by rs2104286 and reported previously using stepwise analysis; and a more complex model with two association signals, one of which was tagged by the major T1D associated rs12722496 and the other by rs56382813. There is low to moderate LD between rs2104286 and both rs12722496 and rs56382813 (r² ≃ 0:3) and our two SNP model could not be recovered through a forward stepwise search after conditioning on rs2104286. Both signals in the two variant model for MS affect CD25 expression on distinct subpopulations of CD4⁺ T cells, which are key cells in the autoimmune process. The results support a shared causal variant for T1D and MS. Our study illustrates the benefit of using a purposely designed model search strategy for fine mapping and the advantage of combining disease and protein expression data.

Genetic association studies have identified many DNA sequence variants that associate with disease risk. By exploiting the known correlation that exists between neighbouring variants in the genome, inference can be extended beyond those individual variants tested to identify sets within which a causal variant is likely to reside. However, this correlation, particularly in the presence of multiple disease causing variants in relative proximity, makes disentangling the specific causal variants difficult. Statistical approaches to this fine mapping problem have traditionally taken a stepwise search approach, beginning with the most associated variant in a region, then iteratively attempting to find additional associated variants. We adapted a stochastic search approach that avoids this stepwise process and is explicitly designed for dealing with highly correlated predictors to the fine mapping problem. We showed in simulated data that it outperforms its stepwise counterpart and other variable selection strategies such as the lasso. We applied our approach to understand the association of two immune-mediated diseases to a region on chromosome 10p15. We identified a model for multiple sclerosis containing two variants, neither of which was found through a stepwise search, and functionally linked both of these to the neighbouring candidate gene, IL2RA, in independent data. Our approach can be used to aid fine mapping of other disease-associated regions, which is critical for design of functional follow-up studies required to understand the mechanisms through which genetic variants influence disease.

Widespread seasonal gene expression reveals annual differences in human immunity and physiology

Seasonal variations are rarely considered a contributing component to human tissue function or health, although many diseases and physiological process display annual periodicities. Here we find more than 4,000 protein-coding mRNAs in white blood cells and adipose tissue to have seasonal expression profiles, with inverted patterns observed between Europe and Oceania. We also find the cellular composition of blood to vary by season, and these changes, which differ between the United Kingdom and The Gambia, could explain the gene expression periodicity. With regards to tissue function, the immune system has a profound pro-inflammatory transcriptomic profile during European winter, with increased levels of soluble IL-6 receptor and C-reactive protein, risk biomarkers for cardiovascular, psychiatric and autoimmune diseases that have peak incidences in winter. Circannual rhythms thus require further exploration as contributors to various aspects of human physiology and disease.

IL-21 production by CD4+ effector T cells and frequency of circulating follicular helper T cells are increased in type 1 diabetes patients

AIMS/HYPOTHESIS

Type 1 diabetes results from the autoimmune destruction of insulin-secreting pancreatic beta cells by T cells. Despite the established role of T cells in the pathogenesis of the disease, to date, with the exception of the identification of islet-specific T effector (Teff) cells, studies have mostly failed to identify reproducible alterations in the frequency or function of T cell subsets in peripheral blood from patients with type 1 diabetes.

METHODS

We assessed the production of the proinflammatory cytokines IL-21, IFN-γ and IL-17 in peripheral blood mononuclear cells from 69 patients with type 1 diabetes and 61 healthy donors. In an additional cohort of 30 patients with type 1 diabetes and 32 healthy donors, we assessed the frequency of circulating T follicular helper (Tfh) cells in whole blood. IL-21 and IL-17 production was also measured in peripheral blood mononuclear cells (PBMCs) from a subset of 46 of the 62 donors immunophenotyped for Tfh.

RESULTS

We found a 21.9% (95% CI 5.8, 40.2; p = 3.9 × 10(-3)) higher frequency of IL-21(+) CD45RA(-) memory CD4(+) Teffs in patients with type 1 diabetes (geometric mean 5.92% [95% CI 5.44, 6.44]) compared with healthy donors (geometric mean 4.88% [95% CI 4.33, 5.50]). Consistent with this finding, we found a 14.9% increase in circulating Tfh cells in the patients (95% CI 2.9, 26.9; p = 0.016).

CONCLUSIONS/INTERPRETATION

These results indicate that increased IL-21 production is likely to be an aetiological factor in the pathogenesis of type 1 diabetes that could be considered as a potential therapeutic target.

Responses of estuarine nematodes to an increase in nutrient supply: an in situ continuous addition experiment

An experiment was carried out on an estuarine mudflat to assess impacts of inorganic nutrients used to fertilize sugar-cane fields on the surrounding aquatic ecosystem, through changes in the nematode community structure. During 118 days, nine quadrats each 4m(2) were sampled six times after the beginning of fertilizer addition. The fertilizer was introduced weekly in six areas, at two different concentrations (low and high doses), and three areas were used as control. The introduction of nutrients modified key nematode community descriptors. In general, the nematodes were negatively affected over the study period. However, Comesa, Metachromadora, Metalinhomoeus, Spirinia and Terschellingia were considered tolerant, and other genera showed different degrees of sensitivity. Nutrient input also affect the availability and quality of food, changing the nematode trophic structure. The use of inorganic fertilizer should be evaluated with care because of the potential for damage to biological communities of coastal aquatic systems.

Multi-parametric flow cytometric and genetic investigation of the peripheral B cell compartment in human type 1 diabetes

The appearance of circulating islet-specific autoantibodies before disease diagnosis is a hallmark of human type 1 diabetes (T1D), and suggests a role for B cells in the pathogenesis of the disease. Alterations in the peripheral B cell compartment have been reported in T1D patients; however, to date, such studies have produced conflicting results and have been limited by sample size. In this study, we have performed a detailed characterization of the B cell compartment in T1D patients (n = 45) and healthy controls (n = 46), and assessed the secretion of the anti-inflammatory cytokine interleukin (IL)-10 in purified B cells from the same donors. Overall, we found no evidence for a profound alteration of the B cell compartment or in the production of IL-10 in peripheral blood of T1D patients. We also investigated age-related changes in peripheral B cell subsets and confirmed the sharp decrease with age of transitional CD19(+) CD27(-) CD24(hi) CD38(hi) B cells, a subset that has recently been ascribed a putative regulatory function. Genetic analysis of the B cell compartment revealed evidence for association of the IL2-IL21 T1D locus with IL-10 production by both memory B cells (P = 6·4 × 10(-4) ) and islet-specific CD4(+) T cells (P = 2·9 × 10(-3) ). In contrast to previous reports, we found no evidence for an alteration of the B cell compartment in healthy individuals homozygous for the non-synonymous PTPN22 Trp(620) T1D risk allele (rs2476601; Arg(620) Trp). The IL2-IL21 association we have identified, if confirmed, suggests a novel role for B cells in T1D pathogenesis through the production of IL-10, and reinforces the importance of IL-10 production by autoreactive CD4(+) T cells.