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In 208 children seeking medical care, the seropositivity rate of anti–SARS-CoV-2 IgG antibodies was 8.7%, suggesting an infection rate similar to that observed in adults but >100-fold the incidence of RT-PCR–confirmed pediatric cases. Compared with the gold-standard combined ELISA + immunofluorescence, the MEDsan IgG rapid diagnostic test performed accurately.

Aims Autoantibodies against apolipoprotein A-1 (anti-apoA-1 IgGs) have emerged as an independent biomarker for cardiovascular disease and mortality in humans, promote death in ApoE−/− mice, and seem to be preferentially oriented against the c-terminal part of apoA-1 (cterA1). Corresponding specific mimetic peptides were shown to reverse anti-apoA-1 IgG pro-inflammatory effects in vitro. We evaluated the association of IgG against c-terminus apoA-1 (anti-cterA1 IgGs) with all-cause mortality in the community and tested the ability of two cterA1 mimetic peptides to reverse the anti-apoA-1 IgG-induced inflammation in vitro and mortality in ApoE−/− mice. Methods Anti-cterA1 IgGs were measured on serum samples of 5220 consecutive participants included in the CoLaus study with median follow-up duration of 5.6 years. The primary study outcome was all-cause mortality. Two chemically engineered optimized cterA1 mimetic peptides were tested i) on HEK cells to modulate interleukin-8 (IL-8) and tumor necrosis-alpha (TNF-α) production, and ii) in apoE−/− mice exposed to 16 weeks of anti-apoA-1 IgG passive immunisation. Results Anti-cterA1 IgG independently predicted all-cause mortality, each standard deviation of anti-cterA1 IgG being associated with a 18% increase in mortality risk (Hazard Ratio:1.18, 95%confidence intervals:1.04–1.33; p=0.009). Both cterA1 mimetic peptides reduced the anti-apoA-1 IgG-induced inflammation in a dose-dependent manner in vitro, but did not rescue the anti-apoA-1 IgG-associated mortality in mice. Conclusions Anti-cterA1 IgG independently predict all-cause mortality in the general population. By failing to reverse the anti-apoA-1 IgG-induced mortality in mice, our data do not support the hypothesis that these autoantibodies could be actionable through cognate peptides immunomodulation. Funding Acknowledgement Type of funding source: Private grant(s) and/or Sponsorship. Main funding source(s): This work was supported by a grant from the Leenaards Foundation (grant number 3698 to N.V.) by the Swiss National Science Foundation (grant number 310030-163335 to N.V.) and by the De Reuter Foundation (grant number 315112 to N.V.).

Objective— We aimed to determine whether autoantibodies against apoA-1 (apolipoprotein A-1; anti-apoA-1 IgG) predict incident coronary artery disease (CAD), defined as adjudicated incident myocardial infarction, angina, percutaneous coronary revascularization, or bypass grafting, in the general population. We further investigated whether this association is modulated by a functional CD14 receptor single nucleotide polymorphism. Approach and Results— In a prospectively studied, population-based cohort of 5220 subjects (mean age 52.6±10.7 years, 47.4% males), followed over a median period of 5.6 years, subjects positive versus negative for anti-apoA-1 IgG presented a total CAD rate of 3.9% versus 2.8% ( P =0.077) and a nonfatal CAD rate of 3.6% versus 2.3% ( P =0.018), respectively. After multivariate adjustment for established cardiovascular risk factors, the hazard ratios of anti-apoA-1 IgG for total and nonfatal CAD were: hazard ratio=1.36 (95% confidence interval, 0.94–1.97; P =0.105) and hazard ratio=1.53 (95% confidence interval, 1.03–2.26; P =0.034), respectively. In subjects with available genetic data for the C260T rs2569190 single nucleotide polymorphism in the CD14 receptor gene (n=4247), we observed a significant interaction between anti-apoA-1 IgG and rs2569190 allele status with regards to CAD risk, with anti-apoA-1 IgG conferring the highest risk for total and nonfatal CAD in non-TT carriers, whereas being associated with the lowest risk for total and nonfatal CAD in TT homozygotes ( P for interaction =0.011 and P for interaction =0.033, respectively). Conclusions— Anti-apoA-1 IgG are independent predictors of nonfatal incident CAD in the general population. The strength of this association is dependent on a functional polymorphism of the CD14 receptor gene, a finding suggesting a gene–autoantibody interaction for the development of CAD.

Objectives Autoantibodies against apolipoprotein A1 (anti‐apoA1 IgGs) and its C‐terminal region (cter apoA1) have emerged as an independent biomarker for cardiovascular disease. Cter apoA1 mimetic peptides were shown to reverse the deleterious anti‐apoA1 IgG effects in vitro. We evaluated the association of anti‐cter apoA1 IgGs with overall mortality in the general population and tested the ability of a cter apoA1 mimetic peptide to reverse the anti‐apoA1 IgG‐induced inflammatory response and mortality in vitro and in vivo, respectively. Methods Anti‐cter apoA1 IgGs were measured in serum samples of 6386 participants of the CoLaus study of which 5220 were followed for a median duration of 5.6 years. The primary outcome was overall mortality. The peptide inhibitory concentration 50% (IC50) was determined in vitro on HEK‐Blue‐4 and RAW cells. ApoE−/− mice were exposed to 16 weeks of anti‐apoA1IgG passive immunisation with and without peptide co‐incubation. Results Anti‐cter apoA1 IgGs were associated with higher interleukin 6 levels and independently predicted overall mortality; an increase of one standard deviation of anti‐cter apoA1 IgG level was associated with an 18% increase in mortality risk (hazard ratio: 1.18, 95% confidence interval: 1.04–1.33; P = 0.009). The cterApoA1 analogue reversed the antibody‐mediated inflammatory response with an IC50 of 1 µm in vitro but did not rescue the significant anti‐apoA1 IgG‐induced mortality rate in vivo (69% vs. 23%, LogRank P = 0.02). Conclusion Anti‐cter apoA1 IgG independently predicts overall mortality in the general population. Despite being effective in vitro, our cter apoA1 analogue did not reverse the anti‐apoA1 IgG‐induced mortality in mice. Our data suggest that these autoantibodies are not readily treatable through cognate peptide immunomodulation., Autoantibodies against apolipoprotein A1 (anti‐apoA1 IgGs) have emerged as an independent cardiovascular risk factor in different settings including in the general population and seem to be preferentially oriented against the its C‐terminal region (cterA1) in humans. In this translational work, we extend previous knowledge in the field by demonstrating for the first time that anti‐cterA1 IgGs are independently predictive of premature mortality in a large general population sample of 5220 individuals. Furthermore, we also report that, despite being effective in vitro, our cterA1 analogue did not reverse the significant anti‐apoA1 IgG‐induced mortality in mice.

Autoantibodies against apolipoprotein A-I (anti-apoA-I IgGs) are prevalent in atherosclerosis-related conditions. It remains elusive whether they improve the prognostic accuracy of the Global Registry of Acute Coronary Events (GRACE) score 2.0 (GS) in acute coronary syndromes (ACS). In this prospective multicenter registry, 1713 ACS patients were included and followed for 1 year. The primary endpoint (major adverse cardiovascular events (MACE)) was defined as the composite of myocardial infarction, stroke (including transient ischemic attack), or cardiovascular (CV) death with individual events independently adjudicated. Plasma levels of anti-apoA-I IgGs upon study inclusion were assessed using ELISA. The association between anti-apoA-I IgGs and incident MACE was assessed using Cox models with splines and C-statistics. One-year MACE incidence was 8.4% (144/1713). Anti-apoA-I IgG levels were associated with MACE with a non-linear relationship (p = 0.01), which remained unchanged after adjusting for the GS (p = 0.04). The hazard increased progressively across the two first anti-apoA-I IgG quartiles before decreasing thereafter. Anti-apoA-I IgGs marginally improved the prognostic accuracy of the GS (c-statistics increased from 0.68 to 0.70). In this multicenter study, anti-apoA-I IgGs were predictive of incident MACE in ACS independently of the GS but in a nonlinear manner. The practical implications of these findings remain to be defined.

IntroductionIn this study, we investigate whether the addition of biomarkers to a model based on traditional risk factors improves risk prediction and patient selection for revascularization in atherosclerotic renovascular disease.MethodsPatients in the Salford Renovascular Study who had the following biomarkers analysed on a baseline sample were included in this study: FGF-23, Cystatin C, kidney injury molecule-1, myeloperoxidase, neutrophil gelatinase-associated lipocalin, N-terminal prohormone of brain natriuretic peptide (NT-proBNP), high-sensitivity Troponin T and anti-apolipoprotein A1 IgG. Cox proportional hazards models and net reclassification index were used to study the effects of either individual or a panel of biomarkers on predicting death, end-stage kidney disease and cardiovascular events.ResultsA total of 112 patients were followed up for a median 59.9 months (IQR 33.6–86.9). In total, 75 patients died, 21 reached end-stage kidney disease and 36 suffered a cardiovascular event. Only NT-proBNP maintained a statistically significant association with all end-points (death: HR 1.62 [95% CI 1.26–2.10], P ConclusionsNT-proBNP is independently associated with increased risk for all adverse events in atherosclerotic renovascular disease. Novel biomarkers may have an incremental risk predictive value when used in combination with traditional risk factors, and NT-proBNP may have value in patient selection for revascularization. Given the small size of this study, larger multicentre studies are required to validate these findings.

Background Autoantibodies against apolipoprotein A1 (anti-apoA1 IgG) have emerged as an independent biomarker for cardiovascular disease and mortality. Across studies, different ELISA methods have been used to measure the level of circulating anti-apoA1 IgG which could lead to substantial result differences between assays. Objectives To make a comparative study of available anti-apoA1 IgG detection methods and to determine whether the choice of matrix sample (serum vs plasma) could influence the results. Methods Blood samples were obtained from 160 healthy blood donors and collected on 4 different matrixes (serum, plasma-EDTA, -citrate, -lithium-heparinate). Anti-apoA1 IgG was measured using two homemade (Geneva's and Lisbon's) and one commercial ELISA kits. Passing-Bablok and Bland-Altman were used to compare the results. Anti-apoA1 IgG seropositivity cut-offs were defined according to the user's/manufacturer's criterion. Results The current results showed substantial differences between those 3 assays. The dynamic ranges were significantly different, the commercial kit displaying the narrowest one. Passing-Bablok analysis demonstrated important proportional and constant biases between assays. The anti-apoA1 IgG seropositivity rate in Geneva, Lisbon and commercial assays varied between 24.5% and 1.9%. Matrix comparisons demonstrated that the matrix choice (plasma versus serum) influenced anti-apoA1 IgG results as well as the seropositivity rate in an assay-dependent manner. The coating antigen source was identified as important factor underlying results heterogeneity across assays. Conclusions These results highlight the impact of the method and the cut-off used on anti-apoA1 IgG results and emphasize the need of standardizing existing assays. Given the important matrix influence, we suggest to use serum as matrix of choice.

SummaryWe aimed to determine the association between autoantibodies against apolipoprotein A-1 (anti-apoA-1 IgG) and prevalent cardiovascular (CV) disease (CVD) as well as markers of CV risk in the general population. Cross-sectional data were obtained from 6649 subjects (age 52.6 ± 10.7 years, 47.4 % male) of the population-based CoLaus study. CVD was defined as myocardial infarction, angina pectoris, percutaneous revascularisation or bypass grafting for ischaemic heart disease stroke or transient ischaemic attack, and was assessed according to standardised medical records. Anti-apoA-1 IgG and biological markers were measured by ELISA and conventional automated techniques, respectively. Prevalence of high anti-apoA-1 IgG levels in the general population was 19.9 %. Presence of anti-apoA-1 IgG was significantly associated with CVD [odds ratio 1.34, 95 % confidence interval (1.05–1.70), p=0.018], independently of established CV risk factors (CVRFs) including age, sex, hypertension, smoking, diabetes, low and high-density lipoprotein cholesterol levels. The n=455 (6.8 %) study participants with a history of CVD (secondary prevention subgroup) presented higher median anti-ApoA-1 IgG values compared with subjects without CVD (p=0.029). Among patients in the secondary prevention subgroup, those with positive anti-apoA-1 IgG levels had lower HDL (p=0.002) and magnesium (p=0.001) levels, but increased uric acid and high-sensitivity C-reactive protein levels (p=0.022, and p

Autoantibodies have been shown to play a critical role in predicting major adverse cardiovascular events in atherosclerotic patients. We aimed to assess the diagnostic accuracy of autoantibodies to apolipoprotein A-1 (anti-apoA-1 IgG) and to phosphorylcholine (anti-PC IgM) for non-ST segment elevation acute myocardial infarction (NSTEMI) and to explore their potential prognostic value. This prospective multicentre study included 1072 patients presenting to the emergency department for suspected NSTEMI. The final diagnosis was adjudicated by two independent cardiologists. For both antibodies alone or expressed as a ratio (anti-apoA-1 IgG/anti-PC IgM), we determined their (i) diagnostic accuracy for NSTEMI and (ii) prognostic accuracy for major adverse cardiovascular events (MACE) during 1-year follow-up. A total of 154 patients (14%) had a final diagnosis of NSTEMI. Diagnostic accuracy for the diagnosis of NSTEMI as quantified by the area under the receiver operating characteristics curve (AUC) was very low for both autoantibodies separately as well as combined as a ratio: AUC anti-apoA-1 IgG 0.50 (95%CI, 0.47-0.53, P = 0.99), AUC anti-PC IgM 0.53 (95%CI, 0.50-0.56, P = 0.30) and AUC of the ratio 0.52 (95%CI, 0.49-0.55, P = 0.47). Adding the anti-apoA-1 IgG/Anti-PC IgM ratio to hs-cTnT did not provide incremental diagnostic value over hs-cTnT alone. MACE occurred in 221 patients (21%) during follow-up. The autoantibodies, separately or expressed as ratio, also had very low accuracy to predict MACE (p=ns). Anti-apoA-1 IgG and anti-PC IgM autoantibodies did not have diagnostic or prognostic value in patients with NSTEMI.

Objectives To determine the impact of long distance rowing (160 km, nonstop) on standard biological parameters and to study the relation between inflammation, myocardial necrosis , lipid profile , heart rate and energy expenditure. Methods Electrolytes, lipid profile, C-reactive protein (CRP), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), procalcitonin (PCT), high-sensitive troponin T (hs-cTnT), and N-terminal pro-brain natriuretic peptide (NT-proBNP), were measured on non-fasting venous blood samples collected 8 h before and after the rowing race on five healthy competitors. Heart rate and energy expenditure were measured using sporting self-measurement devices. Results After 16.5 h of race, significant increases in median CRP (+ 25.2 mg/l; p = 0.04), IL-6 (+ 1.85 pg/ml; p = 0.04), TNF-α (+ 1.2 pg/ml; p = 0.04) and NT-proBNP levels (+ 88.8 pg/ml; p = 0.04) were observed, and a close to significant elevation for hs-cTnT(+ 6 ng/l; p = 0.06) and PCT (+ 0.14 μg/l; p = 0.07). On the other hand, significant decrease in median total cholesterol (− 0.5 mmol/l; p = 0.04), triglycerides (− 0.7 mmol/l; p = 0.04) were observed. Furthermore, significant correlations between the maximal heart rate reached during the race and CRP (r = 0.90; p = 0.03), IL-6 (r = 0.90; p = 0.03), and NT-proBNP (r = 0.90; p = 0.03) were observed, whereas no such associations were retrieved with median heart rate, the percentage of time passed over 70% of maximal heart rate or energy expenditure during the race. There was no association between PCT, NT-proBNP, hs-cTnT, inflammatory biomarkers, lipid profile or heart rate parameters. Conclusions Long distance rowing induces inflammation and myocardial strain related to the maximal effort generated during the race, but has a favourable effect on lipid profile.

Background Autoantibodies against apolipoprotein A-1 (anti-apoA-1 IgG) have emerged as an independent biomarker for cardiovascular disease and mortality. However, their association with all-cause mortality in the community, as well as their genetic determinants, have not been studied. Objective To determine whether anti-apoA-1 IgG: (a) predict all-cause mortality in the general population and (b) are associated with single-nucleotide polymorphisms (SNPs) in a genome-wide association study (GWAS). Methods Clinical, biological, and genetic data were obtained from the population-based, prospective CoLaus study, including 5,220 participants (mean age 52.6 years, 47.3% men) followed over a median duration of 5.6 years. The primary study outcome was all-cause mortality. Results After multivariate adjustment, anti-apoA-1 IgG positivity independently predicted all-cause mortality: hazard ratio (HR) = 1.54, 95% confidence interval (95% CI): 1.11–2.13, P = 0.01. A dose–effect relationship was also observed, each SD of logarithmically transformed anti-apoA-1 IgG being associated with a 15% increase in mortality risk: HR = 1.15, 95% CI: 1.02–1.28, P = 0.028. The GWAS yielded nine SNPs belonging to the Fc receptor-like 3 (FCRL3) gene, which were significantly associated with anti-apoA-1 IgG levels, with the lead SNP (rs6427397, P = 1.54 × 10−9) explaining 0.67% of anti-apoA-1 IgG level variation. Conclusion Anti-apoA-1 IgG levels (a) independently predict all-cause mortality in the general population and (b) are linked to FCRL3, a susceptibility gene for numerous autoimmune diseases. Our findings indicate that preclinical autoimmunity to anti-apoA-1 IgG may represent a novel mortality risk factor.

Autoantibodies to apolipoprotein A-1 (anti-ApoA-1 IgG) were shown to predict major adverse cardiovascular events and promote atherogenesis. However, their potential relationship with clinical disability and ischaemic lesion volume after acute ischaemic stroke (AIS) remains unexplored.We included n = 76 patients admitted for AIS and we investigated whether baseline serum anti-ApoA-1 IgG levels could predict (i) AIS-induced clinical disability [assessed by the modified Rankin Scale (mRS)], and (ii) AIS-related ischaemic lesion volume [assessed by Computed Tomography (CT)]. We also evaluated the possible pro-apoptotic and pro-necrotic effects of anti-ApoA-1 IgG on human astrocytoma cell line (U251) using flow cytometry.High levels of anti-ApoA-1 IgG were retrieved in 15·8% (12/76) of patients. Increased baseline levels of anti-ApoA-1 IgG were independently correlated with worse mRS [β = 0·364; P = 0·002; adjusted odds ratio (OR): 1·05 (95% CI 1·01-1·09); P = 0·017] and CT-assessed ischaemic lesion volume [β = 0·333; P0·001; adjusted OR: 1·06 (95% CI 1·01-1·12); P = 0·048] at 3 months. No difference in baseline clinical, biochemical and radiological characteristics was observed between patients with high vs. low levels of anti-ApoA-1 IgG. Incubating human astrocytoma cells with anti-ApoA-1 IgG dose dependently induced necrosis and apoptosis of U251 cells in vitro.Anti-ApoA-1 IgG serum levels at AIS onset are associated with poorer clinical recovery and worse brain lesion volume 3 months after AIS. These observations could be partly explained by the deleterious effect of anti-ApoA-1 IgG on human brain cell survival in vitro and may have clinical implication in the prediction of poor outcome in AIS.

SummaryHumoral autoimmune-mediated inflammation plays a role in atherogenesis, and potentially in arterial thrombosis. Anti-apolipoprotein A-1 (apoA-1) IgG have been reported to represent emergent mediators of atherogenesis through Toll-like receptors (TLR) 2, 4 and CD14 signalling. We investigated the role of anti-apoA-1 IgG on tissue factor (TF) expression and activation, a key coagulation regulator underlying atherothrombosis. Atherothrombosis features were determined by immunohistochemical TF staining of human carotid biopsies derived from patients with severe carotid stenosis undergoing elective surgery (n=176), and on aortic roots of different genetic backgrounds mice (ApoE-/-; TLR2-/-ApoE-/- and TLR4-/-ApoE-/-) exposed to passive immunisation with anti-apoA-1 IgG. Human serum levels of anti-apoA-1 IgG were measured by ELISA. In vitro, on human-monocyte-derived-macrophages (HMDM) the anti-apoA-1 IgG increased TF expression and activity were analysed by FACS and chromogenic assays in presence of different pharmacological inhibitors. Human serum anti-apoA-1 IgG levels significantly correlated to intraplaque TF expression in carotid biopsies (r=0.31, p

In vitro and animal studies point to autoantibodies against apolipoprotein A-1 (anti-apoA-1 IgG) as possible mediators of cardiovascular (CV) disease involving several mechanisms such as basal heart rate interference mediated by a mineralocorticoid receptor–dependent L-type calcium channel activation, and a direct pro-inflammatory effect through the engagement of the toll-like receptor (TLR) 2/CD14 complex. Nevertheless, the possible implication of these receptors in the pro-arrhythmogenic effect of anti-apoA-1 antibodies remains elusive. We aimed at determining whether CD14 and TLRs could mediate the anti-apoA-1 IgG chronotropic response in neonatal rat ventricular cardiomyocytes (NRVC). Blocking CD14 suppressed anti-apoA-1 IgG binding to NRVC and the related positive chronotropic response. Anti-apoA-1 IgG alone induced the formation of a TLR2/TLR4/CD14 complex, followed by the phosphorylation of Src, whereas aldosterone alone promoted the phosphorylation of Akt by phosphatidylinositol 3-kinase (PI3K), without affecting the chronotropic response. In the presence of both aldosterone and anti-apoA-1 IgG, the localization of TLR2/TLR4/CD14 was increased in membrane lipid rafts, followed by PI3K and Src activation, leading to an L-type calcium channel–dependent positive chronotropic response. Pharmacological inhibition of the Src pathway led to the decrease of L-type calcium channel activity and abrogated the NRVC chronotropic response. Activation of CD14 seems to be a key regulator of the mineralocorticoid receptor–dependent anti-apoA-1 IgG positive chronotropic effect on NRVCs, involving relocation of the CD14/TLR2/TLR4 complex into lipid rafts followed by PI3K and Src-dependent L-type calcium channel activation.

INTRODUCTION Autoimmune mediated inflammation may play a role in atherosclerosis and atherothrombosis essential features for cardiovascular disease (CVD) manifestations. Anti Apolipoprotein A 1 (ApoA 1) IgG autoantibodies are an independent predictor of poor cardiovascular outcome in different clinical settings promote inflammation and atherogenesis and are associated with increased atherosclerotic plaque vulnerability in humans and mice. AIM To determine whether anti ApoA 1 IgG are associated with Tissue Factor (TF) expression a key regulator of the extrinsic coagulation pathway involved in atherothrombosis responsible for the majority of acute CVD manifestations. METHODS Atherothrombosis features were explored in vivo by immunohistochemical TF staining on human carotid atherosclerotic plaques from (n = 102) patients with severe carotid stenosis and in vitro on human monocyte derived macrophages (HMDM) TF expression and pro coagulant activity detected by cytofluorimetry and chromogenic assay respectively. RESULTS In vivo atherosclerotic biopsies derived from patients with high circulating levels of anti apoA 1 IgG (n = 20) displayed a higher TF expression when compared to biopsies from patients with low anti apoA 1 IgG levels (9.3 vs 3.3 p