Autoimmune Nature of Influenza Atherogenicity

Virus-Associated CD8+ T-Cells Are Not Activated Through Antigen-Mediated Interaction Inside Atherosclerotic Lesions

INTRODUCTION

Viral infections have been associated with the progression of atherosclerosis and CD8+ T-cells directed against common viruses, such as influenza, Epstein-Barr virus, and cytomegalovirus, have been detected inside human atherosclerotic lesions. These virus-specific CD8+ T-cells have been hypothesized to contribute to the development of atherosclerosis; however, whether they affect disease progression directly remains unclear. In this study, we aimed to characterize the activation status of virus-specific CD8+ T-cells in the atherosclerotic lesion.

METHODS

The presence, clonality, tissue enrichment, and phenotype of virus-associated CD8+ T-cells in atherosclerotic lesions were assessed by exploiting bulk T-cell receptor-β sequencing and single-cell T-cell receptor (α and β) sequencing datasets on human endarterectomy samples and patient-matched blood samples. To investigate if virus-specific CD8+ T-cells can be activated through T-cell receptor stimulation in the atherosclerotic lesion, the immunopeptidome of human plaques was determined.

RESULTS

Virus-associated CD8+ T-cells accumulated more in the atherosclerotic lesion (mean=2.0%), compared with patient-matched blood samples (mean=1.4%; P=0.05), and were more clonally expanded and tissue enriched in the atherosclerotic lesion in comparison with nonassociated CD8+ T-cells from the lesion. Single-cell T-cell receptor sequencing and flow cytometry revealed that these virus-associated CD8+ T-cells were phenotypically highly similar to other CD8+ T-cells in the lesion and that both exhibited a more activated phenotype compared with circulating T-cells. Interestingly, virus-associated CD8+ T-cells are unlikely to be activated through antigen-specific interactions in the atherosclerotic lesion, as no virus-derived peptides were detected on HLA-I in the lesion.

CONCLUSIONS

This study suggests that virus-specific CD8+ T-cells are tissue enriched in atherosclerotic lesions; however, their potential contribution to inflammation may involve antigen-independent mechanisms.

Hepatitis C Infection as a Risk Factor for Hypertension and Cardiovascular Diseases: An EpiTer Multicenter Study

Hepatitis C infection is one of the main reasons for liver cirrhosis and hepatocellular carcinoma. In recent years, more and more is being heard about extrahepatic manifestations of the hepatitis C infection including its possible influence on the development of hypertension and cardiovascular diseases. In the given work, the frequency analysis of the incidence of hypertension and cardiovascular diseases among 2898 HCV-infected patients treated in Poland and the assessment of their relevance to the HCV genotype and the progression of liver fibrosis can be found. The prevalence of hypertension in the group of analyzed patients was 39% and was significantly associated with old age (OR = 1.08 (1.07-1.08)) and female sex, as well as the progression of liver fibrosis (OR = 1.54 (1.29-1.85)). Hypertension was found in 47.6% of patients with F4 fibrosis, 42.1% of patients with F3 fibrosis, and 25% of patients with F1 fibrosis. The incidence of cardiovascular disease in the studied group of patients was as follows: all incidents, 131 (4.52%); including ischemic heart disease 104, (3.95%); stroke, 2 (0.07%); atherosclerosis, 21 (0.72%); and aneurysms, 4 (0.14%). The obtained results prove that the prevalence of cardiovascular diseases is significantly associated with the advanced age of patients and the progression of liver fibrosis. The relevance of sex and the HCV genotype to the prevalence frequency of cardiovascular diseases in the study group has not been proven. This being the case, no differences in the frequency of their incidence depending on the HCV genotype, including genotype 3, was found. Hepatitis C infection as a non-classical risk factor for cardiovascular disease and hypertension does require further studying.

Influenza and sudden unexpected death: the possible role of peptide cross-reactivity

This study investigates the hypothesis that cross-reactions may occur between human cardiac proteins and influenza antigens, thus possibly representing the molecular mechanism underlying influenzaassociated sudden unexpected death (SUD). Using titin protein as a research model, data were obtained on (1) the occurrence of the titin octapeptide AELLVLLE or its mimic AELLVALE in influenza A virus hemagglutinin (HA) sequences; (2) the immunological potential of AELLVLLE and its mimic AELLVALE; (3) the possible role of the flanking amino acid aa) context of the two octapeptide determinants in eliciting cross-reactivity between the human cardiac titin protein and HA antigens.

Influenza-Associated Hospitalizations for Cardiovascular Diseases in the Tropics

Influenza is a major cause of mortality and morbidity. We aimed to examine the influenza-associated hospitalization rates and proportions for cardiovascular disease (CVD) in tropical Singapore. Hospital admissions for ischemic heart disease (IHD), congestive heart failure (CHF), and overall CVD were obtained from the national inpatient database for the period of 2010-2014. We used, as the key indicator of influenza virus activity, the overall proportion of specimens from outpatients with influenza-like illness in the community that tested positive for influenza as part of the national influenza surveillance program. The annual influenza-associated hospitalization rates per 100,000 person-years ranged from 9.5 to 12.2 for IHD, 7.7 to 9.1 for CHF, and 15.8 to 19.2 for overall CVD. The influenza-associated hospitalization rates increased with increasing age. Influenza was significantly associated with excess hospitalizations in elderly persons aged ≥80 years, with an excess hospitalization rate per 100,000 person-years of 242.7 for IHD (P = 0.02), 271.8 for CHF (P = 0.01), and 497.2 for overall CVD (P < 0.001). In the tropics, influenza accounts for excess cardiovascular-related hospitalizations, especially in the elderly.

Influenza vaccination in north Indian patients with heart failure

Background

No data exists regarding the uptake of influenza vaccination in patients with heart failure (HF) in India. The present study was designed to assess the uptake, knowledge, attitude and practices of the Indian HF patients towards influenza vaccination.

Methods and results

Five-hundred patients with acute/chronic HF were approached for a personal interview and responses to an interview recorded in a pre-defined questionnaire depicting their knowledge, attitudes and practice regarding influenza vaccination. Of the 500 approached, 320 (64%, 174 male, age 3–90 years) consented to participate in the survey. Only 7.5% (n = 24) knew of influenza as an illness with adverse potential consequences for themselves or their family. Seventeen (5.3%) were aware of potentially serious nature of influenza and 40 (12.5%) knew of the availability of a vaccine against it and its local availability. However only 14 (4.4%) had actually received the vaccine 1–2 times in the past 5 years. Only 21 (6.56%) had been prescribed influenza vaccine by their respective physicians. Reasons for declining vaccination included misperceptions about safety and efficacy of the vaccine. Most of the participants, however, had not been prescribed vaccination at all.

Conclusions

Poor influenza vaccination rates in HF mandate intense efforts to improve vaccination rates.

Influenza vaccine for cardiovascular risk reduction

Cardiovascular disease is a leading cause of morbidity and mortality. Individuals with underlying cardiovascular disease are at high risk for adverse outcomes from influenza infections. Although additional studies are needed, current evidence suggests the influenza vaccine may reduce the risk of cardiovascular death and coronary events. In addition to their overall efforts to encourage influenza vaccination for all eligible persons, pharmacists should pay special attention to these high-risk individuals.

Endothelial cell death and intimal foam cell accumulation in the coronary artery of infected hypercholesterolemic minipigs

Apoptosis of endothelial cells (ECs) has been suggested to play a role in atherosclerosis. We studied the synergism of hypercholesterolemia with Chlamydia pneumoniae and influenza virus infections on EC morphology and intimal changes in a minipig model. The coronary artery was excised at euthanasia (19 weeks of age) and serial sections were processed for the detection of EC apoptosis, histology, and transmission electron microscopy (TEM) studies. There was a significantly higher number of TUNEL-positive ECs in infected compared to noninfected groups [0.2942 % (interquartile ranges (IR), 0.2941; n = 26) versus 0 % (IR, 0; n = 12), p < 0.01]. Caspase-3 staining was negative. Cholesterol diet together with infections induced widening of the subendothelial space and appearance of increased numbers of foam cells. TEM revealed degenerative changes in cytoplasmic organelles and signs of EC necrosis. In conclusion, infection leads to an increase in coronary EC death and seems to exacerbate cholesterol-induced intimal thickening and foam cell accumulation.

Novel anti-inflammatory strategies in atherosclerosis

PURPOSE OF REVIEW

Inflammation has been widely acknowledged to contribute throughout all stages of atherogenesis. However, these recent advances in our understanding have not been translated into clinical practice in which the mainstay of treatment is still lipid-targeted therapy. This review provides an overview of promising anti-inflammatory therapies in atherosclerosis, and discusses potential drawbacks and clinical benefits.

RECENT FINDINGS

Immunosuppressive drugs are likely to beneficially affect atherogenesis. Several novel anti-inflammatory targets have been scrutinized, of which some have reached clinical development stage, such as cytokine targets interleukin-1 and interleukin-6, CCR2 antagonist, selective phospholipase, and leukotriene inhibitors. Novel imaging modalities such as MRI and PET-computed tomography provide valuable surrogate inflammatory endpoints for risk stratification and testing anti-inflammatory agents in cardiovascular randomized trials.

SUMMARY

Anti-inflammatory therapies hold great promise in cardiovascular prevention regimens; however, atherosclerosis is a chronic disease, and systemic long-term use of anti-inflammatory agents carries the risk of complications arising from immunosuppression. In order to successfully add immunosuppressive drugs to our routine armament, we need to identify high-risk patients who benefit from anti-inflammatory treatment, increase our insight into the inflammatory pathogenesis of atherogenesis, and find safe and effective compounds capable of directly suppressing plaque inflammation.

Influenza vaccination and cardiovascular morbidity and mortality: analysis of 292,383 patients

Studies have documented an association between influenza vaccination and risk reduction in myocardial infarction, all-cause mortality, and major adverse cardiac events. This meta-analysis pooled data from 5 trials with a total of 292 383 patients. Influenza vaccination was found to be associated with significant reductions in myocardial infarction, all-cause mortality, and major adverse cardiac events. The risk reduction afforded by vaccination and the lack of major adverse events related to the influenza vaccination makes it particularly important to vaccinate those with a known cardiovascular disease or those at high risk of developing cardiovascular disease.

Influenza and autoimmunity

Influenza infection can cause mild to severe illness and can even lead to death. The best way to prevent infection is vaccination against influenza. Complications of influenza infection are not only a consequence of acute infection but can also present as late autoimmune response. Influenza is not frequently implicated as a trigger for autoimmune diseases, but case reports of autoimmune adverse events have been published even following influenza vaccination. In this article we review published data on autoimmune diseases following influenza infection and vaccination. We also discuss immunity of influenza infection in connection to pathogenesis of autoimmune response and autoimmune disease.

Effectiveness of MF59-adjuvanted subunit influenza vaccine in preventing hospitalisations for cardiovascular disease, cerebrovascular disease and pneumonia in the elderly

Annual circulation of influenza virus coincides with a peak in cardiovascular and pneumonia mortality/morbidity. This study aimed to determine the effectiveness of MF59-adjuvanted subunit influenza vaccine in preventing hospitalisation due to acute coronary syndrome (ACS), cerebrovascular accident (CVA) and pneumonia in the elderly. Three case-control studies were performed during the 2004-2005 influenza season in three health districts in Valencia, Spain (total elderly [>64 years of age] population: n=105,454). Controls were patients admitted for an acute surgical process or trauma within 10 days of case admission. In total, 159 patients were hospitalised for ACS, 148 for CVA and 242 for pneumonia. The risk of hospitalisation after the start of the influenza season was significantly lower in vaccinated patients compared with non-vaccinated patients (adjusted odds ratios: 0.13 [P=0.013] for ACS; 0.07 [P=0.007] for CVA; 0.31 [P=0.005] for pneumonia). During peak virus circulation, vaccination with MF59-adjuvanted subunit influenza vaccine was associated with an 87% relative risk reduction in hospitalisation for ACS, 93% for CVA, and 69% for pneumonia.

Influenza Vaccination as Secondary Prevention for Cardiovascular Disease

Evidence from cohort studies and a randomized clinical trial indicates that annual vaccination against seasonal influenza prevents cardiovascular morbidity and all-cause mortality in patients with cardiovascular conditions. The American Heart Association and American College of Cardiology recommend influenza immunization with inactivated vaccine (administered intramuscularly) as part of comprehensive secondary prevention in persons with coronary and other atherosclerotic vascular disease (Class I, Level B). Immunization with live, attenuated vaccine (administered intranasally) is not currently recommended for persons with cardiovascular conditions. It is important to note that influenza vaccination coverage levels overall and in this population remain well below national goals and are marked by disparities across different age and ethnic groups. One of the barriers to vaccination for patients with cardiovascular disease is that cardiology practices frequently do not stock and administer influenza vaccine. Healthcare providers who treat individuals with cardiovascular disease can help improve influenza vaccination coverage rates by providing and strongly recommending vaccination to their patients before and throughout the influenza season.

Influenza vaccination as secondary prevention for cardiovascular disease: a science advisory from the American Heart Association/American College of Cardiology

Evidence from cohort studies and a randomized clinical trial indicates that annual vaccination against seasonal influenza prevents cardiovascular morbidity and all-cause mortality in patients with cardiovascular conditions. The American Heart Association and American College of Cardiology recommend influenza immunization with inactivated vaccine (administered intramuscularly) as part of comprehensive secondary prevention in persons with coronary and other atherosclerotic vascular disease (Class I, Level B). Immunization with live, attenuated vaccine (administered intranasally) is not currently recommended [corrected] for persons with cardiovascular conditions. It is important to note that influenza vaccination coverage levels overall and in this population remain well below national goals and are marked by disparities across different age and ethnic groups. One of the barriers to vaccination for patients with cardiovascular disease is that cardiology practices frequently do not stock and administer influenza vaccine. Healthcare providers who treat individuals with cardiovascular disease can help improve influenza vaccination coverage rates by providing and strongly recommending vaccination to their patients before and throughout the influenza season.

Influenza vaccination among cardiovascular disease sufferers in Spain: related factors and trend, 1993-2003

Based on data drawn from the 1993 and 2003 National Health Surveys (NHS), we sought to: estimate influenza vaccination coverages among Spanish cardiovascular disease (CVD) sufferers; study which variables were associated with the likelihood of being vaccinated; analyze the time-trend in coverage for the period 1993-2003. For study purposes, a CVD sufferer was defined as any adult who reported suffering from high blood pressure and/or heart disease. The proportion of vaccinated adult CVD sufferers in 1993 and 2003 totalled 39.96% and 51.73%, respectively. The following variables increased the likelihood of being vaccinated: higher age; male gender; presence of respiratory chronic diseases; non-smoker status. Coverages for CVD sufferers had improved significantly from 1993 to 2003 but still remain below desirable levels. The improvement over time is mainly due to the subgroup aged >64 years. Strategies must be implemented to improve the use of influenza vaccine among CVD sufferers in Spain in general, and among the younger age-groups in particular.