The Impact of Concomitant Diagnosis of Viral Infections on in-Hospital Mortality in Patients Hospitalized with a Diagnosis of Heart Failure in the United States: Insights from the National Inpatient Sample

The impact of viral infections on patients admitted with a diagnosis of heart failure is not well understood. We conducted a retrospective cohort study using data from the National Inpatient Sample in the United States to evaluate the proportion of admissions with a diagnosis of heart failure and viral infections, and we explored how viral infections had impact on in-hospital mortality and length of stay. There were a total of 20,713,539 admission records with a diagnosis of heart failure included in the analysis and 3.8% had a concomitant diagnosis of viral infection. The mean length of stay was 20.1 ± 26.9 days, 12.9 ± 13.6 days, 12.1 ± 13.8 days, and 5.1 ± 6.5 days for records with a diagnosis of cytomegalovirus, viral meningitis/encephalitis, herpes simplex infection, and no viral infection, respectively. The most common diagnoses of viral infections were influenza (n = 240,260) and chronic viral hepatitis (n = 194,400), and the highest rates of mortality were observed for records with a diagnosis of cytomegalovirus (13.2%), acute viral hepatitis (12.5%), and viral meningitis/encephalitis (11.1%). The viral infections significantly associated with increased odds of mortality were cytomegalovirus infection (OR 1.84 95% CI 1.57-2.16), acute hepatitis (OR 1.29 95% CI 1.15-1.45), and HIV (OR 1.22 95% CI 1.11-1.34). In conclusion, viral infections are co-diagnosis in 3.8% of patient records with heart failure and detection of some viruses may be important as they increase mortality and may prolong length of stay in hospital.

CMV Infection Is Directly Related to the Inflammatory Status in Chronic Heart Failure Patients

High levels of inflammation play an important role in chronic heart failure (CHF). Patients with CHF have elevated levels of pro-inflammatory cytokines circulating systemically, mainly TNF and IL-6. However, there are almost no studies that relate these levels to the functional status of patients in CHF, much less to their CMV serostatus. In this study, patients with CHF (n=40; age=54.9 ± 6.3; New York Heart Association functional classification (NYHA, I-III) and healthy controls (n=40; age=53.5 ± 7.1) were analyzed. The serum concentrations of nine pro- and anti-inflammatory cytokines were measured by Luminex^® xMap Technology and the basal level of mRNA expression of some immune molecules was quantified by TaqMan™ Array in CD4+ T-lymphocytes. The concentration of these cytokines in culture supernatants in response to anti-CD3 and LPS was also measured. The percentage of CD28null T-cells was determined, as well as the antibody titer against CMV. We found a higher concentration of all cytokines studied in CHF serum compared to healthy controls, as well as a direct correlation between functional status in CHF patients and levels of inflammatory cytokines. Moreover, the highest cytokine concentrations were found in patients with higher concentrations of lymphocytes lacking CD28 molecule. The cytokine production was much higher in CMV+ patients, and the production of these cytokines was found mainly in the T-lymphocytes of CMV+ patients in response to anti-CD3. Anti-CMV antibody levels were positively correlated with cytokine levels. The baseline expression of specific mRNA of the main molecules involved in the Th1 response, as well as molecules related to the CD4+CD28 null subset was higher in CMV+ patients. The cytokine concentrations are higher in CHF CMV+ patients and these concentrations are related to the production of antibodies against CMV. These high levels of cytokines are also associated with the more differentiated CD28null lymphocyte populations. All this, together with the dynamics of the pathology itself, makes CMV+ patients present a worse functional status and possibly a worse evolution of the pathology.

Cytomegalovirus Infection in Cardiovascular Diseases

Atherosclerosis underlies the development of many cardiovascular diseases that continue to hold a leading place among the causes of death in developed countries. The role of activated immune cells in atherosclerosis progression has been convincingly demonstrated, but the mechanism of their action remains poorly investigated. Since atherosclerosis is associated with chronic inflammatory response, involvement of viral and bacterial infections in atherogenesis has been examined. A special place among the infectious agents is held by human herpesviruses as the most common persistent viruses in human population coupled to chronic inflammation during atherosclerosis. We found that activation of cytomegalovirus (CMV, human herpesvirus 5) infection is associated with the emergence of acute coronary syndrome, which is in a good agreement with the data on productive CMV infection published elsewhere. In this review, we discuss the data obtained by us and other researchers regarding the role of cytomegalovirus infection and related potential mechanisms resulting in the expansion of atherosclerotic plaques during ischemic heart disease and stroke, including virus transfer to immune and endothelial cells via extracellular vesicles. In particular, the data presented in the review demonstrate that virus spreading in the vascular wall triggers immune system activation in atherosclerotic plaques and causes endothelial dysfunction. Moreover, productive CMV infection in patients with acute myocardial infarction correlates with the extent of endothelial dysfunction. The mechanisms described by us and other researchers may explain the role of CMV infection in atherosclerosis and development of ischemic heart disease.

Arterial Stiffness Is Associated With Cytomegalovirus-Specific Senescent CD8+ T Cells

Background

Arterial stiffness is a well‐known predictor of future cardiovascular events. Search for the underlying mechanism of arterial stiffening is still under way. We investigated the relationship between arterial stiffness and cytomegalovirus infection in terms of T‐cell senescence.

Methods and Results

Arterial stiffness was evaluated using pulse wave velocity measurements in 415 Koreans (age 59±12 years). We also investigated the frequency of CD57⁺ or CD28^null senescent T cells in peripheral blood lymphocytes and analyzed which immune parameters were correlated with pulse wave velocity. Furthermore, cytomegalovirus‐specific T cells were stimulated with overlapping peptides covering pp65 protein, and T‐cell function was evaluated by intracellular cytokine staining of interferon‐γ, tumor necrosis factor‐α, and CD107a. In a multivariate analysis, it was found that the frequency of CD57⁺ cells in the CD8⁺ T‐cell subset was independently correlated with pulse wave velocity after adjusting for traditional cardiovascular risk factors such as age, sex, diabetes mellitus history, smoking history, body mass index, blood pressure, serum creatinine, high‐density lipoprotein cholesterol, and high‐sensitivity C‐reactive protein. Cytomegalovirus pp65‐specific T cells were more frequently observed in the CD8⁺CD57⁺ population than in the CD8⁺CD57⁻ population, and multivariate analysis revealed that the frequency of cytomegalovirus pp65‐specific interferon‐γ⁺, tumor necrosis factor‐α⁺, or CD107a⁺ cells in the CD8⁺ T‐cell subset was independently correlated with pulse wave velocity as well.

Conclusions

We demonstrate that arterial stiffness is associated with senescent CD57⁺ T cells and CMV pp65‐specific T cells in the CD8⁺ T‐cell subset. The precise role of cytomegalovirus‐specific, senescent T cells in vascular aging needs to be further investigated.

T cell senescence and cardiovascular diseases

Age-related changes in the immune system, commonly termed "immunosenescence," contribute to deterioration of the immune response and fundamentally impact the health and survival of elderly individuals. Immunosenescence affects both the innate and adaptive immune systems; however, the most notable changes are in T cell immunity and include thymic involution, the collapse of T cell receptor (TCR) diversity, an imbalance in T cell populations, and the clonal expansion of senescent T cells. Senescent T cells have the ability to produce large quantities of proinflammatory cytokines and cytotoxic mediators; thus, they have been implicated in the pathogenesis of many chronic inflammatory diseases. Recently, an increasing body of evidence has suggested that senescent T cells also have pathogenic potential in cardiovascular diseases, such as hypertension, atherosclerosis, and myocardial infarction, underscoring the detrimental roles of these cells in various chronic inflammatory responses. Given that cardiovascular disease is the number one cause of death worldwide, there is great interest in understanding the contribution of age-related immunological changes to its pathogenesis. In this review, we discuss general features of age-related alterations in T cell immunity and the possible roles of senescent T cells in the pathogenesis of cardiovascular disease.

Presence of human cytomegalovirus DNA in blood of patients with community-acquired pneumonia

After a primary infection, human cytomegalovirus (HCMV) remains latent in certain human cells. Different stimuli, including immune deficiency and severe infection, can trigger the reactivation of latent HCMV infection. In the last decade, the role of the reactivation in immunocompetent patients with serious illness has been intensely studied; however, the knowledge of the potential role of moderately severe infections on HCMV dynamics is limited. In the prospective study, 80 HCMV-seropositive, immunocompetent adult patients with community-acquired pneumonia (CAP), treated outside the intensive care unit (ICU), were monitored with real-time polymerase chain reaction (PCR) for the presence of HCMV DNA. Detection of HCMV DNA in whole blood and/or plasma was interpreted as reactivation of latent HCMV infection. HCMV DNA was detected in 6 of 80 (7.5%) patients. All HCMV DNA-positive patients were classified according to the pneumonia severity index (PSI) as high-risk classes IV or V; thus, HCMV DNAaemia rate within these two PSI classes was 16.7%. All of the patients had positive whole blood samples, whereas plasma samples were positive in a single patient. We did not detect any significant differences comparing six patients with proven HCMV DNAaemia and 74 patients in whom HCMV DNAaemia was not demonstrated regarding the levels of inflammatory parameters on admission, length of treatment with supplemental oxygen, and length of hospital stay. In conclusion, the finding of HCMV DNAaemia in patients with CAP treated outside the ICU is a rare event and occurs only in patients with PSI classes designating more severe pneumonia.

Resistant pathogens, fungi, and viruses

Although originally described in Staphylococcus aureus, resistance among bacteria has now become a race to determine which classes of bacteria will become more resistant. Availability of antibacterial agents has allowed the development of entirely new diseases caused by nonbacterial pathogens, related largely to fungi that are inherently resistant to antibacterials. This article presents the growing body of knowledge of the herpes family of viruses, and their occurrence and consequences in patients with concomitant surgical disease or critical illness. The focus is on previously immunocompetent patients, as the impact of herpes viruses in immunosuppressed patients has received thorough coverage elsewhere.

Frequent detection of cytomegalovirus (CMV) DNA in the lower respiratory tract in CMV-seropositive pediatric patients with underlying chronic bronchopulmonary diseases lacking canonical immunosuppression

Cytomegalovirus (CMV) may be a relevant cause of morbidity in patients displaying various inflammatory diseases. In this study, it was investigated whether CMV DNA is detected in the lower respiratory tract and the systemic compartment in pediatric patients with chronic or recurrent bronchopulmonary diseases. A total of 42 lower respiratory tract specimens and 11 paired plasma samples from 42 patients were analyzed for the presence of CMV DNA by real‐time PCR. The respiratory specimens were also screened for the presence of respiratory viruses and human herpesvirus 6 (HHV‐6) and 7 (HHV‐7) by PCR methods. Quantitative bacterial and fungal cultures were performed. IL‐6 levels in the respiratory specimens were quantified using ELISA. CMV DNA was detected either in the lower respiratory airways, in plasma, or both in 54.5% of CMV‐seropositive patients. The levels of IL‐6 were significantly higher in these patients than in those with no detectable levels of CMV DNA. HHV‐6 and HHV‐7 DNA were detected in three and one patients, respectively. Respiratory viruses were detected in 13 of the 42 patients. Significant growth of one or more bacterial species was observed in 17 patients. No significant association was found between the presence of CMV DNA and the detection of other microorganisms. The data indicated that the presence of CMV DNA in the lower respiratory tract is a frequent finding in children with chronic or recurrent bronchopulmonary diseases. Further, prospective observational studies are needed to assess the impact of this phenomenon, if any, on the clinical course of these patients. J. Med. Virol. 85:888–892, 2013. © 2013 Wiley Periodicals, Inc.