Cytomegalovirus and human immunosenescence

Anti-cytomegalovirus antibody levels stratify human immune profiles across the lifespan

Human cytomegalovirus (hCMV) is a ubiquitous latent persistent herpesvirus infecting 60-90% of the population worldwide. hCMV carriage in immunocompetent people is asymptomatic; thus, hCMV can be considered a component of normative aging. However, hCMV powerfully modulates many features of the immune, and likely other, systems and organs. Questions remain as to how hCMV carriage affects the human host. We used anti-CMV antibody titers as a stratifying criterion to examine the impact of "intensity" of hCMV infection as a potential biomarker of aging, inflammation, and immune homeostasis in a cohort of 247 participants stratified into younger (21-40 years) and older (> 65 years of age) groups. We showed that anti-CMV antibody titers increased with age and directly correlated to increased levels of soluble tumor necrosis factor (sTNFR) I in younger but not older participants. CD8 + cell numbers were reduced in the older group due to the loss in CD8 + T naïve (Tn) cells. In CMV carriers and, in particular, in anti-CMV Ab-high participants, this loss was mitigated or reversed by an increase in the numbers of CD8 + T effector memory (Tem) and T effector memory reexpressing CD45RA (Temra) cells. Analysis of CD38, HLA-DR, and CD57 expression revealed subset (CD4 or CD8)-specific changes that correlated with anti-CMV Ab levels. In addition, anti-CMV Ab levels predicted anti-CMV CD8 T cell responsiveness to different CMV open reading frames (ORFs) selectively in older participants, which correlated to the transcriptional order of expression of specific CMV ORFs. Implications of these results for the potential predictive value of anti-CMV Ab titers during aging are discussed.

Viral infections in etiology of mental disorders: a broad analysis of cytokine profile similarities - a narrative review

The recent pandemic caused by the SARS-CoV-2 virus and the associated mental health complications have renewed scholarly interest in the relationship between viral infections and the development of mental illnesses, a topic that was extensively discussed in the previous century in the context of other viruses, such as influenza. The most probable and analyzable mechanism through which viruses influence the onset of mental illnesses is the inflammation they provoke. Both infections and mental illnesses share a common characteristic: an imbalance in inflammatory factors. In this study, we sought to analyze and compare cytokine profiles in individuals infected with viruses and those suffering from mental illnesses. The objective was to determine whether specific viral diseases can increase the risk of specific mental disorders and whether this risk can be predicted based on the cytokine profile of the viral disease. To this end, we reviewed existing literature, constructed cytokine profiles for various mental and viral diseases, and conducted comparative analyses. The collected data indicate that the risk of developing a specific mental illness cannot be determined solely based on cytokine profiles. However, it was observed that the combination of IL-8 and IL-10 is frequently associated with psychotic symptoms. Therefore, to assess the risk of mental disorders in infected patients, it is imperative to consider the type of virus, the mental complications commonly associated with it, the predominant cytokines to evaluate the risk of psychotic symptoms, and additional patient-specific risk factors.

sCD163, sCD28, sCD80, and sCTLA-4 as soluble marker candidates for detecting immunosenescence

BACKGROUND

Inflammaging, the characteristics of immunosenescence, characterized by continuous chronic inflammation that could not be resolved. It is not only affect older people but can also occur in young individuals, especially those suffering from chronic inflammatory conditions such as autoimmune disease, malignancy, or chronic infection. This condition led to altered immune function and as consequent immune function is reduced. Detection of immunosenescence has been done by examining the immune risk profile (IRP), which uses flow cytometry. These tests are not always available in health facilities, especially in developing countries and require fresh whole blood samples. Therefore, it is necessary to find biomarkers that can be tested using stored serum to make it easier to refer to the examination. Here we proposed an insight for soluble biomarkers which represented immune cells activities and exhaustion, namely sCD163, sCD28, sCD80, and sCTLA-4. Those markers were reported to be elevated in chronic diseases that caused early aging and easily detected from serum samples using ELISA method, unlike IRP. Therefore, we conclude these soluble markers are beneficial to predict pathological condition of immunosenescence.

AIM

To identify soluble biomarkers that could replace IRP for detecting immunosenescence.

CONCLUSION

Soluble costimulatory molecule suchsCD163, sCD28, sCD80, and sCTLA-4 are potential biomarkers for detecting immunosenescence.

Understanding the health effects of caregiving stress: New directions in molecular aging

Dementia caregiving has been linked to multiple health risks, including infectious illness, depression, anxiety, immune dysregulation, weakened vaccine responses, slow wound healing, hypertension, cardiovascular disease, metabolic syndrome, diabetes, frailty, cognitive decline, and reduced structural and functional integrity of the brain. The sustained overproduction of proinflammatory cytokines is a key pathway behind many of these risks. However, contrasting findings suggest that some forms of caregiving may have beneficial effects, such as maintaining caregivers' health and providing a sense of meaning and purpose which, in turn, may contribute to lower rates of functional decline and mortality. The current review synthesizes these disparate literatures, identifies methodological sources of discrepancy, and integrates caregiver research with work on aging biomarkers to propose a research agenda that traces the mechanistic pathways of caregivers' health trajectories with a focus on the unique stressors facing spousal caregivers as compared to other informal caregivers. Combined with a focus on psychosocial moderators and mechanisms, studies using state-of-the-art molecular aging biomarkers such as telomere length, p16INK4a, and epigenetic age could help to reconcile mixed literature on caregiving's sequelae by determining whether and under what conditions caregiving-related experiences contribute to faster aging, in part through inflammatory biology. The biomarkers predict morbidity and mortality, and each contributes non-redundant information about age-related molecular changes -together painting a more complete picture of biological aging. Indeed, assessing changes in these biopsychosocial mechanisms over time would help to clarify the dynamic relationships between caregiving experiences, psychological states, immune function, and aging.

Cytomegalovirus durably primes neutrophil oxidative burst

Cytomegalovirus (CMV) is a ubiquitous herpes virus that infects most humans, thereafter persisting lifelong in tissues of the host. It is a known pathogen in immunosuppressed patients, but its impact on immunocompetent hosts remains less understood. Recent data have shown that CMV leaves a significant and long-lasting imprint in host immunity that may confer some protection against subsequent bacterial infection. Such innate immune activation may come at a cost, however, with potential to cause immunopathology. Neutrophils are central to many models of immunopathology, and while acute CMV infection is known to influence neutrophil biology, the impact of chronic CMV infection on neutrophil function remains unreported. Using our murine model of CMV infection and latency, we show that chronic CMV causes persistent enhancement of neutrophil oxidative burst well after resolution of acute infection. Moreover, this in vivo priming of marrow neutrophils is associated with enhanced formyl peptide receptor expression, and ultimately constitutive c-Jun N-terminal kinase phosphorylation and enhanced CD14 expression in/on circulating neutrophils. Finally, we show that neutrophil priming is dependent on viral load, suggesting that naturally infected human hosts will show variability in CMV-related neutrophil priming. Altogether, these findings represent a previously unrecognized and potentially important impact of chronic CMV infection on neutrophil responsiveness in immunocompetent hosts.

Cytomegalovirus and Cardiovascular Disease: A Hypothetical Role for Viral G-Protein-Coupled Receptors in Hypertension

Cytomegalovirus (CMV) is a member of the β-herpesviruses and is ubiquitous, infecting 50%-99% of the human population depending on ethnic and socioeconomic conditions. CMV establishes lifelong, latent infections in their host. Spontaneous reactivation of CMV is usually asymptomatic, but reactivation events in immunocompromised or immunosuppressed individuals can lead to severe morbidity and mortality. Moreover, herpesvirus infections have been associated with several cardiovascular and post-transplant diseases (stroke, atherosclerosis, post-transplant vasculopathy, and hypertension). Herpesviruses, including CMV, encode viral G-protein-coupled receptors (vGPCRs) that alter the host cell by hijacking signaling pathways that play important roles in the viral life cycle and these cardiovascular diseases. In this brief review, we discuss the pharmacology and signaling properties of these vGPCRs, and their contribution to hypertension. Overall, these vGPCRs can be considered attractive targets moving forward in the development of novel hypertensive therapies.

Senescent T cells: Beneficial and detrimental roles

As the thymus involutes during aging, the T-cell pool has to be maintained by the periodic expansion of preexisting T cells during adulthood. A conundrum is that repeated episodes of activation and proliferation drive the differentiation of T cells toward replicative senescence, due to telomere erosion. This review discusses mechanisms that regulate the end-stage differentiation (senescence) of T cells. Although these cells, within both CD4 and CD8 compartments, lose proliferative activity after antigen-specific challenge, they acquire innate-like immune function. While this may confer broad immune protection during aging, these senescent T cells may also cause immunopathology, especially in the context of excessive inflammation in tissue microenvironments.

Aging and chronic inflammation: highlights from a multidisciplinary workshop

Aging is a gradual, continuous series of natural changes in biological, physiological, immunological, environmental, psychological, behavioral, and social processes. Aging entails changes in the immune system characterized by a decrease in thymic output of naïve lymphocytes, an accumulated chronic antigenic stress notably caused by chronic infections such as cytomegalovirus (CMV), and immune cell senescence with acquisition of an inflammatory senescence-associated secretory phenotype (SASP). For this reason, and due to the SASP originating from other tissues, aging is commonly accompanied by low-grade chronic inflammation, termed "inflammaging". After decades of accumulating evidence regarding age-related processes and chronic inflammation, the domain now appears mature enough to allow an integrative reinterpretation of old data. Here, we provide an overview of the topics discussed in a recent workshop "Aging and Chronic Inflammation" to which many of the major players in the field contributed. We highlight advances in systematic measurement and interpretation of biological markers of aging, as well as their implications for human health and longevity and the interventions that can be envisaged to maintain or improve immune function in older people.

Premature T cell aging in major depression: A double hit by the state of disease and cytomegalovirus infection

Introduction

Previous research indicates that premature T cell senescence is a characteristic of major depressive disorder (MDD). However, known senescence inducing factors like cytomegalovirus (CMV) infection or, probably, childhood adversity (CA) have not been taken into consideration so far.

Objective

Differentiation and senescent characteristics of T cells of MDD patients were investigated in relation to healthy controls (HC), taking the CMV seropositivity and CA into account.

Methods

127 MDD and 113 HC of the EU-MOODSTRATIFICATION cohort were analyzed. Fluorescence activated cell sorting (FACS) analysis was performed to determine B, NK, and T cell frequencies. In a second FACS analysis, naïve, effector memory (Tem), central memory (Tcm), effector memory cells re-expressing RA (TEMRA), as well as CD28⁺ and CD27⁺ memory populations, were determined of the CD4⁺ and CD8⁺ T cell populations in a subsample (N = 35 MDD and N = 36 HC). CMV-antibody state was measured by IgG ELISA and CA by the Childhood Trauma Questionnaire.

Results

We detected a CMV-antibody positivity in 40% of MDD patients (35% HC, n. s.) with seropositive MDD cases showing a higher total childhood trauma score. Second, a higher inflation of memory CD4⁺ T helper cells in CMV seronegative patients as compared to seronegative HC and reduced numbers of naïve CD4⁺ T helper cells in CMV seropositive patients (not in CMV seropositive HC) were found. Third, a higher inflation of memory CD8⁺ T cytotoxic cells in CMV seropositive cases as compared to CMV seropositive HC, particularly of the TEMRA cells, became apparent. Higher percentages of CD4⁺ TEMRA and late stage CD27^-CD28^- TEMRA cells were similar in both HC and MDD with CMV seropositivity. Overall, apportioning of T cell subpopulations did not differ between CA positive vs negative cases.

Conclusions

MDD patients show several signs of a CMV independent "MDD specific" premature T cell aging, such as a CMV independent increase in CD4⁺ T memory cells and a latent naïve CD4 T-cell reduction and a latent CD8⁺ T-cell increase. However, these two latent T cell senescence abnormalities only become evident with CMV infection (double hit).

Circulating immune cell phenotypes are associated with age, sex, CMV, and smoking status in the Framingham Heart Study offspring participants

Understanding the composition of circulating immune cells with aging and the underlying biologic mechanisms driving aging may provide molecular targets to slow the aging process and reduce age-related disease. Utilizing cryopreserved cells from 996 Framingham Heart Study (FHS) Offspring Cohort participants aged 40 and older (mean 62 years, 48% female), we report on 116 immune cell phenotypes including monocytes, T-, B-, and NK cells and their subtypes, across age groups, sex, cytomegalovirus (CMV) exposure groups, smoking and other cardiovascular risk factors. The major cellular differences with CMV exposure were higher Granzyme B+ cells, effector cells, and effector-memory re-expressing CD45RA (TEMRA) cells for both CD4+ and CD8+. Older age was associated with lower CD3+ T cells, lower naïve cells and naïve/memory ratios for CD4+ and CD8+. We identified many immune cell differences by sex, with males showing lower naïve cells and higher effector and effector memory cells. Current smokers showed lower pro-inflammatory CD8 cells, higher CD8 regulatory type cells and altered B cell subsets. No significant associations were seen with BMI and other cardiovascular risk factors. Our cross-sectional observations of immune cell phenotypes provide a reference to further the understanding of the complexity of immune cells in blood, an easily accessible tissue.

Assessment of the Interferon-Lambda-3 Polymorphism in the Antibody Response to COVID-19 in Older Adults Seropositive for CMV

BACKGROUND

Here, we investigated the impact of IFN-lambda-3 polymorphism on specific IgG responses for COVID-19 in older adults seropositive for CMV.

METHODS

Blood samples of 25 older adults of both sexes were obtained at three different times: during a micro-outbreak (MO) of SARS-CoV-2 in 2020; eight months after (CURE); and 30 days after the administration of the second dose of ChadOx-1 vaccine (VAC). The specific IgG for both SARS-CoV-2 and CMV antigens, neutralizing antibodies against SARS-CoV-2, and also the polymorphism profile for IFN-lambda-3 (rs12979860 C > T) were assessed.

RESULTS

Higher levels of specific IgG for SARS-CoV-2 antigens were found in the MO and VAC than in the CURE time-point. Volunteers with specific neutralizing antibodies against SARS-CoV-2 showed better specific IgG responses for SARS-CoV-2 and lower specific IgG levels for CMV than volunteers without specific neutralizing antibodies. Significant negative correlations between the specific IgG levels for SARS-CoV-2 and CMV were found at the MO time-point, as well as in the group of individuals homozygous for allele 1 (C/C) in the MO time-point and heterozygotes (C/T) in the CURE time-point.

CONCLUSION

Our results suggested that both CMV seropositivity and the homozygosis for allele 1 (C/C) in IFN-lambda-3 gene can negatively impact the antibody response to COVID-19 infection and vaccination in older adults.

Prospective Evaluation of CD45RA+/CCR7- Effector Memory T (TEMRA) Cell Subsets in Patients with Primary and Secondary Brain Tumors during Radiotherapy of the Brain within the Scope of the Prospective Glio-CMV-01 Clinical Trial

Radiotherapy (RT) of the brain is a common treatment for patients with high-grade gliomas and brain metastases. It has previously been shown that reactivation of cytomegalovirus (CMV) frequently occurs during RT of the brain. This causes neurological decline, demands antiviral treatment, and is associated with a worse prognosis. CMV-specific T cells are characterized by a differentiated effector memory phenotype and CD45RA+ CCR7- effector memory T (T_EMRA) cells were shown to be enriched in CMV seropositive individuals. In this study, we investigated the distribution of T_EMRA cells and their subsets in the peripheral blood of healthy donors and, for the first time, prospectively within the scope of the prospective Glio-CMV-01 clinical trial of patients with high-grade glioma and brain metastases during radiation therapy as a potential predictive marker. First, we developed a multicolor flow cytometry-based assay to monitor the frequency and distribution of T_EMRA cells in a longitudinal manner. The CMV serostatus and age were considered as influencing factors. We revealed that patients who had a reactivation of CMV have significantly higher amounts of CD8+ T_EMRA cells. Further, the distribution of the subsets of T_EMRA cells based on the expression of CD27, CD28, and CD57 is highly dependent on the CMV serostatus. We conclude that the percentage of CD8+ T_EMRA cells out of all CD8+ T cells has the potential to serve as a biomarker for predicting the risk of CMV reactivation during RT of the brain. Furthermore, this study highlights the importance of taking the CMV serostatus into account when analyzing T_EMRA cells and their subsets.

Immune aging in multiple sclerosis is characterized by abnormal CD4 T cell activation and increased frequencies of cytotoxic CD4 T cells with advancing age

BACKGROUND

Immunosenescence (ISC) describes age-related changes in immune-system composition and function. Multiple sclerosis (MS) is a lifelong inflammatory condition involving effector and regulatory T-cell imbalance, yet little is known about T-cell ISC in MS. We examined age-associated changes in circulating T cells in MS compared to normal controls (NC).

METHODS

Forty untreated MS (Mean Age 43·3, Range 18-72) and 49 NC (Mean Age 48·6, Range 20-84) without inflammatory conditions were included in cross-sectional design. T-cell subsets were phenotypically and functionally characterized using validated multiparametric flow cytometry. Their aging trajectories, and differences between MS and NC, were determined using linear mixed-effects models.

FINDINGS

MS patients demonstrated early and persistent redistribution of naïve and memory CD4 T-cell compartments. While most CD4 and CD8 T-cell aging trajectories were similar between groups, MS patients exhibited abnormal age-associated increases of activated (HLA-DR+CD38+; (P = 0·013) and cytotoxic CD4 T cells, particularly in patients >60 (EOMES: P < 0·001). Aging MS patients also failed to upregulate CTLA-4 expression on both CD4 (P = 0·014) and CD8 (P = 0·009) T cells, coupled with abnormal age-associated increases in frequencies of B cells expressing costimulatory molecules.

INTERPRETATION

While many aspects of T-cell aging in MS are conserved, the older MS patients harbour abnormally increased frequencies of CD4 T cells with activated and cytotoxic effector profiles. Age-related decreased expression of T-cell co-inhibitory receptor CTLA-4, and increased B-cell costimulatory molecule expression, may provide a mechanism that drives aberrant activation of effector CD4 T cells that have been implicated in progressive disease.

FUNDING

Stated in Acknowledgements section of manuscript.

Effect of Cytomegalovirus on the Immune System: Implications for Aging and Mental Health

Human cytomegalovirus (HCMV) is a major modulator of the immune system leading to long-term changes in T-lymphocytes, macrophages, and natural killer (NK) cells among others. Perhaps because of this immunomodulatory capacity, HCMV infection has been linked with a host of deleterious effects including accelerated immune aging (premature mortality, increased expression of immunosenescence-linked markers, telomere shortening, speeding-up of epigenetic "clocks"), decreased vaccine immunogenicity, and greater vulnerability to infectious diseases (e.g., tuberculosis) or infectious disease-associated pathology (e.g., HIV). Perhaps not surprisingly given the long co-evolution between HCMV and humans, the virus has also been associated with beneficial effects, such as increased vaccine responsiveness, heterologous protection against infections, and protection against relapse in the context of leukemia. Here, we provide an overview of this literature. Ultimately, we focus on one other deleterious effect of HCMV, namely the emerging literature suggesting that HCMV plays a pathophysiological role in psychiatric illness, particularly depression and schizophrenia. We discuss this literature through the lens of psychological stress and inflammation, two well-established risk factors for psychiatric illness that are also known to predispose to reactivation of HCMV.

Immunosenescence, inflammaging, and cancer immunotherapy efficacy

INTRODUCTION

Immunosenescence is a progressive remodeling of immune functions associated with a decreased ability of the immune system to set up an efficient immune response, both innate and adaptive, with an increase of highly differentiated T cells at the expense of naive T cells. The incidence and prevalence of most cancers increase with age, which can partly be explained by tumor escape mechanisms and decreased immunosurveillance. Aging is also associated with inflammaging, a low-grade proinflammatory state characterized by an increase in inflammatory mediators. Anti-cancer immunotherapy has profoundly changed the landscape of oncology therapy in the last 10 years. Modern T-cell targeted therapies such as bispecific T cell engagers, CAR-T cells, or immune checkpoint blockers may be theoretically affected by immunosenescence or inflammaging.

AREAS COVERED

A bibliographic review through PubMed and Embase was carried out using the following search terms: 'immunosenescence,' 'immunotherapy,' 'inflammaging,' 'bispecific antibodies,' 'CAR-T cells,' 'immune checkpoint blockers,' and 'older patients.'

EXPERT OPINION

This review explores the potential impact of immunosenescence and inflammaging on anti-cancer immunotherapy and therapeutic strategies that could counter immune senescence. A more dedicated research on immunosenescence biomarkers in future clinical trials is warranted for the development of new, more effective and safer therapies.

CMV seropositivity is a potential novel risk factor for severe COVID-19 in non-geriatric patients

BACKGROUND

COVID-19 has so far affected more than 250 million individuals worldwide, causing more than 5 million deaths. Several risk factors for severe disease have been identified, most of which coincide with advanced age. In younger individuals, severe COVID-19 often occurs in the absence of obvious comorbidities. Guided by the finding of cytomegalovirus (CMV)-specific T cells with some cross-reactivity to SARS-CoV-2 in a COVID-19 intensive care unit (ICU) patient, we decided to investigate whether CMV seropositivity is associated with severe or critical COVID-19. Herpes simplex virus (HSV) serostatus was investigated as control.

METHODS

National German COVID-19 bio-sample and data banks were used to retrospectively analyze the CMV and HSV serostatus of patients who experienced mild (n = 101), moderate (n = 130) or severe to critical (n = 80) disease by IgG serology. We then investigated the relationship between disease severity and herpesvirus serostatus via statistical models.

RESULTS

Non-geriatric patients (< 60 years) with severe COVID-19 were found to have a very high prevalence of CMV-seropositivity, while CMV status distribution in individuals with mild disease was similar to the prevalence in the German population; interestingly, this was not detectable in older patients. Prediction models support the hypothesis that the CMV serostatus, unlike HSV, might be a strong biomarker in identifying younger individuals with a higher risk of developing severe COVID-19, in particular in absence of other co-morbidities.

CONCLUSIONS

We identified 'CMV-seropositivity' as a potential novel risk factor for severe COVID-19 in non-geriatric individuals in the studied cohorts. More mechanistic analyses as well as confirmation of similar findings in cohorts representing the currently most relevant SARS-CoV-2 variants should be performed shortly.

Age-associated phenotypic imbalance in TCD4 and TCD8 cell subsets: comparison between healthy aged, smokers, COPD patients and young adults

Background

COPD is associated with an abnormal lung immune response that leads to tissue damage and remodeling of the lung, but also to systemic effects that compromise immune responses. Cigarette smoking also impacts on innate and adaptative immune responses, exerting dual, pro- and anti-inflammatory effects. Previously, we showed that COPD patients presented accelerated telomere shortening and decreased telomerase activity, while, paradoxically, cigarette-smokers exhibited preserved telomerase activity and slower rate of telomere shortening.

Results

Here, we evaluated the naive, CM, EM and TEMRA subsets of TCD4 and TCD8 cells according to the expression of CCR7/CD45RA. We compared age-matched COPD patients, cigarette-smokers without clinical-laboratory evidence of pulmonary compromise, and healthy individuals. They were additionally compared with a group of young adults. For each subset we analysed the expression of markers associated with late differentiation, senescence and exhaustion (CD27/CD28/CD57/KLRG1/PD1). We show that COPD patients presented a drastically reduced naive cells pool, and, paradoxically, increased fractions of naive cells expressing late differentiation, senescence or exhaustion markers, likely impacting on their immunocompetence. Pronounced phenotypic alterations were also evidenced in their three memory T-cell subsets compared with the other aged and young groups, suggesting an also dysfunctional memory pool. Surprisingly, our smokers showed a profile closer to the Healthy aged than COPD patients. They exhibited the usual age-associated shift of naive to EM TCD4 and TCD8 cells, but not to CM or TEMRA T-cells. Nonetheless, their naive T-cells phenotypes were in general similar to those of the Youngs and Healthy aged, suggesting a rather phenotypically preserved subset, while the memory T-cells exhibited increased proportions of cells with the late-differentiation or senescence/exhaustion markers as in the Healthy aged.

Conclusion

Our study extends previous findings by showing that COPD patients have cells expressing a full range of late differentiated, senescent or exhausted phenotypes encompassing all TCD4 and TCD8 subsets, consistent with a premature immunosenescence phenotype. Surprisingly, the smokers group’s results suggest that moderate to heavy chronic cigarette smoking did not accelerate the pace of immunosenescence as compared with the Healthy aged.

How Immunosenescence and Inflammaging May Contribute to Hyperinflammatory Syndrome in COVID-19

Aging is characterized by the dynamic remodeling of the immune system designated “immunosenescence,” and is associated with altered hematopoiesis, thymic involution, and lifelong immune stimulation by multitudinous chronic stressors, including the cytomegalovirus (CMV). Such alterations may contribute to a lowered proportion of naïve T-cells and to reduced diversity of the T-cell repertoire. In the peripheral circulation, a shift occurs towards accumulations of T and B-cell populations with memory phenotypes, and to accumulation of putatively senescent and exhausted immune cells. The aging-related accumulations of functionally exhausted memory T lymphocytes, commonly secreting pro-inflammatory cytokines, together with mediators and factors of the innate immune system, are considered to contribute to the low-grade inflammation (inflammaging) often observed in elderly people. These senescent immune cells not only secrete inflammatory mediators, but are also able to negatively modulate their environments. In this review, we give a short summary of the ways that immunosenescence, inflammaging, and CMV infection may cause insufficient immune responses, contribute to the establishment of the hyperinflammatory syndrome and impact the severity of the coronavirus disease 2019 (COVID-19) in elderly people.

Better Response to Influenza Virus Vaccination in Physically Trained Older Adults Is Associated With Reductions of Cytomegalovirus-Specific Immunoglobulins as Well as Improvements in the Inflammatory and CD8+ T-Cell Profiles

Chronic cytomegalovirus (CMV) infection is a trigger factor for the development of immunosenescence and negatively impacts the immune response to influenza virus vaccination (IVV) in older adults. However, the role of physical exercise training in this context is unknown. Thus, the aim of this study was to investigate whether the regular practice of combined exercise training can improve the specific antibody response to IVV in CMV-seropositive older adults. Eighty older adults were distributed into two groups—non-practitioners (NP, n = 31, age = 74.06 ± 6.4 years) and practitioners of combined exercise training (CET, n = 49, age = 71.7 ± 5.8 years)—for at least 12 months. Both volunteer groups were submitted to IVV and blood samples were collected before (pre) and 30 days after (post) the vaccination. Concerning the specific antibody response to IVV, higher serum levels of specific immunoglobulin A (IgA) were found in the CET group post- than pre-vaccination (p < 0.01), whereas higher levels of specific immunoglobulin M (IgM) were observed both in the NP (p < 0.05) and CET (p < 0.001) groups post-vaccination as compared to the pre-vaccination values. Serum levels of specific immunoglobulin G (IgG) for IVV and CMV, as well as interleukin 6 (IL-6) and IL-10, were similar between the time points evaluated. However, the IL-10/IL-6 ratio post-vaccination was higher (p < 0.05) in the CET group than that before vaccination. Negative correlations were observed between the specific IgG levels for IVV and CMV only in the CET group, both pre- and post-vaccination. In addition, negative correlations were found between IL-10 and specific IgG for CMV in all volunteer groups pre- and post-vaccination, whereas a positive correlation between IL-10 and specific-IgG for IVV pre- and post-vaccination was observed in the CET group. In addition, with the hemagglutination inhibition (HAI) assay, it was found that 32.2% of the NP group and 32.6% of the CET group were responders to IVV and displayed reductions in the CMV serostatus (p < 0.05 and p < 0.001, respectively) and increases in naive and effector CD8⁺ T cells post-vaccination (p < 0.01). However, only the responders from the CET group showed significant reductions in the ratio of effector to naive CD8⁺ T cells (p < 0.05) and increased IL-10 levels post-vaccination (p < 0.001). In summary, this study demonstrates that the improvement in the response to IVV in CMV-seropositive older adults was related to an anti-inflammatory status and enhancement of naive CD8⁺ T cells, particularly associated with regular practice of CET.

Functional Changes of T-Cell Subsets with Age and CMV Infection

Cytomegalovirus (CMV) latent infection and aging contribute to alterations in the function and phenotype of the T-cell pool. We have demonstrated that CMV-seropositivity is associated with the expansion of polyfunctional CD57+ T-cells in young and middle-aged individuals in response to different stimuli. Here, we expand our results on the effects of age and CMV infection on T-cell functionality in a cohort of healthy middle-aged and older individuals stratified by CMV serostatus. Specifically, we studied the polyfunctional responses (degranulation, IFN-γ and TNF-α production) of CD4+, CD8+, CD8+CD56+ (NKT-like), and CD4−CD8− (DN) T-cells according to CD57 expression in response to Staphylococcal Enterotoxin B (SEB). Our results show that CD57 expression by T-cells is not only a hallmark of CMV infection in young individuals but also at older ages. CD57+ T-cells are more polyfunctional than CD57− T-cells regardless of age. CMV-seronegative individuals have no or a very low percentages of cytotoxic CD4+ T-cells (CD1017a+) and CD4+CD57+ T-cells, supporting the notion that the expansion of these T-cells only occurs in the context of CMV infection. There was a functional shift in T-cells associated with CMV seropositivity, except in the NKT-like subset. Here, we show that the effect of CMV infection and age differ among T-cell subsets and that CMV is the major driving force for the expansion of highly polyfunctional CD57+ T-cells, emphasizing the necessity of considering CMV serology in any study of immunosenescence.

Activation of Endogenous Retrovirus, Brain Infections and Environmental Insults in Neurodegeneration and Alzheimer's Disease

Chronic neurodegenerative diseases are complex, and their pathogenesis is uncertain. Alzheimer’s disease (AD) is a neurodegenerative brain alteration that is responsible for most dementia cases in the elderly. AD etiology is still uncertain; however, chronic neuroinflammation is a constant component of brain pathology. Infections have been associated with several neurological diseases and viruses of the Herpes family appear to be a probable cause of AD neurodegenerative alterations. Several different factors may contribute to the AD clinical progression. Exogeneous viruses or other microbes and environmental pollutants may directly induce neurodegeneration by activating brain inflammation. In this paper, we suggest that exogeneous brain insults may also activate retrotransposons and silent human endogenous retroviruses (HERVs). The initial inflammation of small brain areas induced by virus infections or other brain insults may activate HERV dis-regulation that contributes to neurodegenerative mechanisms. Chronic HERV activation in turn may cause progressive neurodegeneration that thereafter merges in cognitive impairment and dementia in genetically susceptible people. Specific treatment for exogenous end endogenous pathogens and decreasing pollutant exposure may show beneficial effect in early intervention protocol to prevent the progression of cognitive deterioration in the elderly.

Cytomegalovirus seropositivity is associated with reduced risk of multiple sclerosis-a presymptomatic case-control study

BACKGROUND AND PURPOSE

Epstein-Barr virus (EBV) and human herpesvirus 6A (HHV-6A) are associated with increased risk of multiple sclerosis (MS). Conversely, infection with cytomegalovirus (CMV) has been suggested to reduce the risk of MS but supporting data from presymptomatic studies are lacking. Here, it was sought to increase the understanding of CMV in MS aetiology.

METHODS

A nested case-control study was performed with presymptomatically collected blood samples identified through crosslinkage of MS registries and Swedish biobanks. Serological antibody response against CMV, EBV and HHV-6A was determined using a bead-based multiplex assay. Odds ratio (OR) with 95% confidence interval (CI) for CMV seropositivity as a risk factor for MS was calculated by conditional logistic regression and adjusted for EBV and HHV-6A seropositivity. Potential interactions on the additive scale were analysed by calculating the attributable proportion due to interaction (AP).

RESULTS

Serum samples from 670 pairs of matched cases and controls were included. CMV seropositivity was associated with a reduced risk for MS (OR = 0.70, 95% CI 0.56-0.88, p = 0.003). Statistical interactions on the additive scale were observed between seronegativity for CMV and seropositivity against HHV-6A (AP 0.34, 95% CI 0.06-0.61) and EBV antigen EBNA-1 (amino acid 385-420) at age 20-39 years (AP 0.37, 95% CI 0.09-0.65).

CONCLUSIONS

Cytomegalovirus seropositivity is associated with a decreased risk for MS. The protective role for CMV infection in MS aetiology is further supported by the interactions between CMV seronegativity and EBV and HHV-6A seropositivity.

The Effects of Physical Activity on the Aging of Circulating Immune Cells in Humans: A Systematic Review

Age-induced cellular senescence leads to a decline in efficacy of immune response and an increase in morbidity and mortality. Physical activity may be an intervention to slow down or reverse this process for elderly individuals or even delay it via enhanced activity over their lifespan. The aim of this systematic review was to analyze and discuss the current evidence of the effects of physical activity on senescence in leukocyte subpopulations. Two electronic databases (PubMed, Web of Science) were scanned in July 2020. Studies performing endurance or resistance exercise programs and investigating leukocytes of healthy, particularly elderly subjects were included. Nine human studies were identified, including a total of 440 participants, of which two studies examined different types of exercise training retrospectively, three conducted resistance exercise, three endurance exercise, and one endurance vs. resistance training. Results revealed that exercise training increased the naïve subsets of peripheral T-helper cells and cytotoxic T-cells, whereas the senescent and effector memory T-cells re-expresses CD45RA (TEMRA) subsets decreased. Moreover, the percentage of T-helper- compared to cytotoxic T-cells increased. The results suggest that physical activity reduces or slows down cellular immunosenescence. Endurance exercise seems to affect cellular senescence in a more positive way than resistance training. However, training contents and sex also influence senescent cells. Explicit mechanisms need to be clarified.

Cytomegalovirus and herpes simplex type 1 infections and immunological profile of community-dwelling older adults

Chronic infections, such as cytomegalovirus (CMV) and herpes simplex virus type 1 (HSV-1), contribute to the inflammation process among older adults and are associated with the immunosenescence process. The aim was to identify the immunological profile associated with CMV and HSV-1 infections among older adults. This is a cross-sectional study, carried out with 1492 participants from the Bambuí Cohort Study of Aging - Minas Gerais, Brazil. For analysis purposes, we considered the presence of immunoglobulin G (IgG) for CMV and HSV-1 in the participants' serum, assessed by the enzyme-linked immunosorbent assay (ELISA); outcomes were defined by titration above the median (>160 UR/mL for HSV-1 and >399.5 U/mL for CMV). In order to assess the immunological profile, the following biomarkers were considered: IL-1beta, IL-10, IL-12, TNF, CXCL8, CXCL9, CXCL10, CCL2, CCL5, IL-6 and CRP; the first four being categorized as detectable levels or not, and the others using the Classification and Regression Tree (CART) method. The analysis was adjusted for sociodemographic variables, health behaviors and health conditions. The seroprevalence of anti CMV and anti HSV-1 antibodies was 99.4% and 97.0%, respectively. Higher concentrations of CXCL8 and CCL5 chemokines were associated with lower antibody titers for CMV, and higher concentrations of CXCL9, IL-6 and CRP were associated with higher levels of antibodies to CMV. Moreover, intermediate levels of CXCL10 were also associated with higher levels of antibodies to CMV. In HSV-1 infection, intermediate levels of CXCL9, CCL5 and IL-6 were less likely to have higher antibody titers for this infection. On the other hand, higher levels of CXCL10 and CRP were positively associated with higher antibody titers for HSV-1. The results describe important immunological changes and reinforce the potential effect of CMV and HSV-1 on the immunosenescence process.

Markers of T Cell Exhaustion and Senescence and Their Relationship to Plasma TGF-β Levels in Treated HIV+ Immune Non-responders

Background: Immune non-responders (INR) are HIV+, ART-controlled (>2 yrs) people who fail to reconstitute their CD4 T cell numbers. Systemic inflammation and markers of T cell senescence and exhaustion are observed in INR. This study aims to investigate T cell senescence and exhaustion and their possible association with soluble immune mediators and to understand the immune profile of HIV-infected INR. Selected participants were <50 years old to control for the confounder of older age. Methods: Plasma levels of IL-6, IP10, sCD14, sCD163, and TGF-β and markers of T cell exhaustion (PD-1, TIGIT) and senescence (CD57, KLRG-1) were measured in ART-treated, HIV+ participants grouped by CD4 T cell counts (n = 63). Immune parameters were also measured in HIV-uninfected, age distribution-matched controls (HC; n = 30). Associations between T cell markers of exhaustion and senescence and plasma levels of immune mediators were examined by Spearman rank order statistics. Results: Proportions of CD4 T cell subsets expressing markers of exhaustion (PD-1, TIGIT) and senescence (CD57, KLRG-1) were elevated in HIV+ participants. When comparing proportions between INR and IR, INR had higher proportions of CD4 memory PD-1+, EM CD57+, TEM TIGIT+ and CD8 EM and TEM TIGIT+ cells. Plasma levels of IL-6, IP10, and sCD14 were elevated during HIV infection. IP10 was higher in INR. Plasma TGF-β levels and CD4 cycling proportions of T regulatory cells were lower in INR. Proportions of CD4 T cells expressing TIGIT, PD-1, and CD57 positively correlated with plasma levels of IL-6. Plasma levels of TGF-β negatively correlated with proportions of TIGIT+ and PD-1+ T cell subsets. Conclusions: INR have lower levels of TGF-β and decreased proportions of cycling CD4 T regulatory cells and may have difficulty controlling inflammation. IP10 is elevated in INR and is linked to higher proportions of T cell exhaustion and senescence seen in INR.

Cytomegalovirus retinitis following dexamethasone intravitreal implant

Purpose

To describe a case of Cytomegalovirus (CMV) Retinitis in an immunocompetent patient following Dexamethasone Intravitreal Implant (DII).

Observations

Retrospective chart review of a single patient. An 80-year-old immunocompetent male presented with floaters in his left eye 10 weeks after his DII. He was noted to have a visual acuity of 20/1200 in his left eye and a panuveitis with CMV retinitis. The patient underwent a vitreous biopsy and given immediate intravitreal foscarnet and an ongoing management regimen of oral valganciclovir for two months. His vision improved to 20/200 and his CMV retinitis resolved.

Conclusion and Importance

DII can trigger CMV retinitis in immunocompetent patients.

Efficacy of immune-checkpoint inhibitors (ICI) in the treatment of older adults with metastatic renal cell carcinoma (mRCC) - an International mRCC Database Consortium (IMDC) analysis

OBJECTIVE

Older adults with metastatic renal cell carcinoma(mRCC) are underrepresented in immune-checkpoint inhibitor(ICI) registration trials. Here we compare the efficacy of ICI treatments in older vs. younger adults with mRCC.

METHODS

Using the International mRCC Database Consortium(IMDC), patients treated with a PD(L)-1 based ICI were identified. Older adult was defined as ≥70-years at the time of treatment. Descriptive statistics were summarized in means, medians, and proportions. Effectiveness endpoints included overall survival (OS), time-to-treatment failure(TTF), time-to-next treatment(TNT), and overall response rate(ORR). Hazards ratios were adjusted(aHR) for IMDC risk factors, histology, line of treatment and older age.

RESULTS

Of 1427 included patients, 397(28%) were older adults. ICI was used as 1st line(1 L) in 40%, 2nd line(2 L) in 49% and 3rd line(3 L) in 11% of patients. In univariable analysis, older adults had inferior OS compared to younger adults(25.1 m vs. 30.8 m, p < 0.01). There were no significant differences in TTF (6.9 m vs. 6.9 m, p = 0.4) or TNT(9.1 m vs 10 m, p = 0.3) between groups. In multivariable analyses, older age was not independently associated with worse OS(aHR = 1.02, p = 0.8), TTF(aHR = 0.95, p = 0.6) or TNT(aHR = 0.93, p = 0.5). Older adults had a lower ORR compared to younger adults(24% vs. 31%, p = 0.01), which was mainly driven by responses in 1 L(31% vs. 44%, p = 0.02) and not observed in 2 L/3 L.

CONCLUSIONS

After multivariable analyses, older adults with mRCC treated with ICI had no difference in OS, TTF or TNT when compared to younger adults. Our data support that chronological older age should not preclude patients from receiving ICI based therapies.

Pathogen Burden, Blood Biomarkers and Functional Ageing in Community-Dwelling Older Adults

BACKGROUND

Lifelong accumulation of latent or persistent or repeated infections may be a contributing factor to the deterioration of physical and cognitive function associated with functional ageing, but the evidence is limited and the biological underpinnings are unclear.

METHODS

We profiled the seropositivity for common viral, bacterial and plasmodial pathogens of local importance in community-living older adults in two studies involving 745 older adults (mean age 67.0, SD: 7.7 years), and 142 older adults (mean age 72.7, SD: 8.3 years). Pathogen load was related to different sets of age-related physical and cognitive measures of functional ageing and the frailty index, and plasma levels of biomarkers of inflammation, innate and adaptive immunity, and other physiological functions.

RESULTS

High pathogen load was associated with impaired gait speed (GS), (p<0.015), functional mobility (POMA) (p<0.029), cognitive function (MMSE) (p<<0.05), and increased frailty index (FI) (p<<0.05). High pathogen load was significantly associated with C3a complement activity (p<0.001), matrix metalloproteinase-7, macrophage inflammatory protein-1α (p<0.05), and monocyte chemoattractant protein 2 (p=0.028). Blood biomarkers did not fully explain the observed association between pathogen load and functional ageing measures.

CONCLUSIONS

The present study provides novel evidence linking lifelong cumulated numbers of latent, persistent or repeated infection to functional ageing, plausibly via inflammatory and immune and other biological factors.

Effects of Chronic Viral Infection on Lymphocyte Populations in Middle-aged Baboons (Papio anubis)

Aging of the immune system is characterized by the loss of naïve T-cells, increased inflammation, and immune function impairment. Chronic infection with cytomegalovirus is thought to play a role in age-related changes in immunity. Therefore, to assess the effect of pathogens such as cytomegalovirus on the immune system, we determined lymphocyte populations and inflammatory markers over a 3-y period in captive, middle-age baboons, with various exposure to pathogens and shedding pressure. Groups included SPF (i.e., pathogen-negative; n = 14); large-group, conventionally housed (CONV LG; pathogen- positive; n = 14), and small-group, conventionally housed (CONV SM; pathogen-positive; n = 7). All baboon groups showed a decrease in CD45RA+ CD28+ (i.e., naive) cells over time during middle age, but the rate of decline appeared faster in CONV LG baboons than in the other groups. In addition, the reduction in CD45RA+ CD28+ cells in the CONV LG baboons coincided with higher IgG levels against baboon cytomegalovirus, increased serum cortisol concentration, and a greater inflammatory phenotype. The results of this project support a role for cytomegalovirus infection in immune system alterations in middle-aged baboons.

Cytomegalovirus antibody levels and mortality among hospitalised elderly patients

BACKGROUND

The impact of cytomegalovirus infection in elderly subjects remains unclear. This study examined the relationship between humoral immune response to cytomegalovirus (CMV) and all-cause mortality in a cohort of elderly hospitalised patients.

METHODS

Data were obtained from a random sample of 715 patients (≥65 years old) admitted for any cause in a third level hospital. Serum IgG antibody against CMV was determined by enzyme-linked immunosorbent (ELISA) assay.

RESULTS

A total of 480 deaths occurred in seropositive patients (n = 671) during a follow-up of 7.6 years (mean, 4.6); of which 112 patients died in-hospital or within 30 days after discharge (short-term mortality). For patients with CMV IgG antibody levels in the highest quartile compared with lower quartile, fully adjusted models showed that mortality was 1.40 times (95% CI 1.05-1.86) and 2.20 times (95% CI 1.15-4.21) higher, respectively. The exclusion of patients with cardiovascular disease (angina, myocardial infarction, heart failure, peripheral artery disease, or stroke) increases the risk of long-term (HR 2.22, 95% CI 1.36-3.62) and short-term mortality (OR 3.18, 95% CI 1.40-7.24).

CONCLUSIONS

Increased IgG antibody levels against CMV are associated with increased short and long-term mortality in elderly hospitalised patients, especially in patients without cardiovascular disease. Key Messages The outcome of elderly hospitalised patients in relation to CMV is unknown. We demonstrate an association between increased anti-CMV IgG levels and mortality. This association is greater in elderly patients without cardiovascular disease.

The relationship between Chlamydia pneumoniae infection and CD4/CD8 ratio, lymphocyte subsets in middle-aged and elderly individuals

Chlamydia pneumoniae (C. pneumoniae) is a common respiratory pathogen associated with many inflammatory diseases. There are few data concerning the lymphocyte subsets in middle-aged and elderly individuals with C. pneumoniae infection. A total of 191 patients were included in this study. The study population was categorized into the middle-aged group (40-64 years old) and the elderly group (65-89 years old). Lymphocyte subsets in peripheral blood were examined with multi-colored flow cytometry. Immunological monitoring included lymphocyte subsets, C. pneumoniae IgG and IgM serology. In the middle-aged group, 69.83% individuals presented IgG positivity, which was associated with the inverted CD4/CD8 ratio. Individuals with C. pneumoniae IgG positivity also presented an increased percentage of CD8⁺CD28^- cells and a decreased CD4/CD8 ratio when compared to weakly-positive individuals. In the elderly group, C. pneumoniae IgG positivity was associated with a significant increase in the percentage of CD3⁺CD56⁺CD45⁺ (NKT) cells. In conclusion, altered lymphocyte homeostasis was shown in middle-aged individuals with C. pneumoniae IgG positivity. The senescent phenotypes of T cells might be associated with C. pneumoniae infection in middle-aged individuals.

Exploratory study on immune phenotypes in Alzheimer's disease and vascular dementia

BACKGROUND AND PURPOSE

The differentiation of Alzheimer's disease (AD) dementia from vascular dementia (VaD) and mixed-type dementia (mixed dementia) requires stepwise analysis and usually occurs late in the disease process. Early diagnosis and therapy monitoring would benefit greatly from the identification of biomarkers of neurodegeneration, especially blood biomarkers. To this end, the aim of the present pilot study was to investigate differences in the distribution of peripheral T-cell populations in patients with AD compared to VaD and mixed dementia.

METHODS

Flow cytometry was performed on blood samples from 11 patients with AD, six with VaD and six with mixed dementia, as well as 17 healthy control subjects (HCs). CD4+ and CD8+ T cells were typed for expression of CD45, CD27, CD28, CD25, FoxP3, CCR4 and CCR6; the other leukocytes were also assessed. Functionally, immune cell uptake of the β-amyloid (Aβ) toxic fragment (Aβ_1-42 ) was also evaluated.

RESULTS

A higher proportion of CD4+CD28- memory T cells and a reciprocal reduction of CD4+CD28+CD27+ naïve T lymphocytes was detected in all patient groups relative to controls. Significantly fewer CD4+CD25+FoxP3 regulatory T cells were present in patients with VaD, and significantly more CCR6+ and CCR4+ CD4+ T cells in those with AD. Higher CCR6+ T-cell frequencies were also present in patients with mixed dementia, potentially due to the inflammation and immune cell chemoattraction triggered by Aβ.

CONCLUSIONS

The present study was a comprehensive investigation comparing different kinds of dementia, revealing differentially expressed peripheral markers that are potentially useful for early AD, VaD and mixed dementia diagnoses, and that would assist in proper treatments for these disparate diseases. Validation is now required.

Diagnosis-independent loss of T-cell costimulatory molecules in individuals with cytomegalovirus infection

Major depressive disorder (MDD) is associated with physiological changes commonly observed with increasing age, such as inflammation and impaired immune function. Age-related impaired adaptive immunity is characterized by the loss of naive T-cells and the reciprocal accumulation of memory T-cells together with the loss of T-cell co-stimulatory molecules. Additionally, the presence and activity of cytomegalovirus (CMV) alters the architecture of the T-cell compartment in a manner consistent with premature aging. Because CMV is also thought to reactivate with psychological stress, this study tested whether MDD influences age-related phenotypes of T-cell populations in the context of CMV infection in young and middle-aged adults. Morning blood samples from volunteers with a DSM-IV diagnosis of MDD (n = 98, mean age(SD) = 36(10) years, 74.5% female, 57.1% CMV⁺) and comparison controls (n = 98, mean age(SD) = 34(10) years, 68.4% female, 51.0% CMV⁺) were evaluated for CMV IgG antibody status and the distribution of late differentiated (CD27^-CD28^-) cells within CD4⁺ and CD8⁺ T-cell subsets, i.e. naive (CCR7⁺CD45RA⁺), effector memory (EM, CCR7^-CD45RA^-), central memory (CM, CCR7⁺CD45RA^-) and effector memory cells re-expressing CD45RA (EMRA, CCR7^-CD45RA⁺). Mixed linear regression models controlling for age, sex, ethnicity and flow cytometry batch showed that CMV seropositivity was associated with a reduction in naive T-cells, expansion of EMRA T-cells, and a greater percent distribution of CD27^-CD28^- cells within CD4⁺ and CD8⁺ memory T-cell subsets (p's < 0.004), but there was no significant effect of MDD, nor any significant interaction between CMV and diagnosis. Unexpectedly, depressed men were less likely to be CMV⁺ and depressed women were more likely to be CMV⁺ than sex-matched controls suggesting a possible interaction between sex and MDD on CMV susceptibility, but this three-way interaction did not significantly affect the T-cell subtypes. Our findings suggest that depression in young and middle-aged adults does not prematurely advance aging of the T-cell compartment independently of CMV, but there may be significant sex-specific effects on adaptive immunity that warrant further investigation.

Targeting Infectious Agents as a Therapeutic Strategy in Alzheimer's Disease

Alzheimer's disease (AD) is the most prevalent dementia in the world. Its cause(s) are presently largely unknown. The most common explanation for AD, now, is the amyloid cascade hypothesis, which states that the cause of AD is senile plaque formation by the amyloid β peptide, and the formation of neurofibrillary tangles by hyperphosphorylated tau. A second, burgeoning theory by which to explain AD is based on the infection hypothesis. Much experimental and epidemiological data support the involvement of infections in the development of dementia. According to this mechanism, the infection either directly or via microbial virulence factors precedes the formation of amyloid β plaques. The amyloid β peptide, possessing antimicrobial properties, may be beneficial at an early stage of AD, but becomes detrimental with the progression of the disease, concomitantly with alterations to the innate immune system at both the peripheral and central levels. Infection results in neuroinflammation, leading to, and sustained by, systemic inflammation, causing eventual neurodegeneration, and the senescence of the immune cells. The sources of AD-involved microbes are various body microbiome communities from the gut, mouth, nose, and skin. The infection hypothesis of AD opens a vista to new therapeutic approaches, either by treating the infection itself or modulating the immune system, its senescence, or the body's metabolism, either separately, in parallel, or in a multi-step way.

Age-related factors that affect B cell responses to vaccination in mice and humans

Aging significantly changes the ability to respond to vaccinations and infections. In this review, we summarize published results on age-related changes in response to infection with the influenza virus and on the factors known to increase influenza risk infection leading to organ failure and death. We also summarize how aging affects the response to the influenza vaccine with a special focus on B cells, which have been shown to be less responsive in the elderly. We show the cellular and molecular mechanisms contributing to the dysfunctional immune response of the elderly to the vaccine against influenza. These include a defective interaction of helper T cells (CD4+) with B cells in germinal centers, changes in the microenvironment, and the generation of immune cells with a senescence-associated phenotype. Finally, we discuss the effects of aging on metabolic pathways and we show how metabolic complications associated with aging lead to immune dysfunction.

The direct and indirect consequences of cytomegalovirus infection and potential benefits of vaccination

Active infection with cytomegalovirus (CMV) occurs in patients who are immunocompromised and may produce the high viral loads required to cause end-organ disease. Such patients have complex medical histories and many experienced physicians have speculated that CMV may, additionally, contribute to adverse clinical outcomes. In 1989, Dr Bob Rubin coined the term "indirect effects" to describe this potential relationship between virus and patient. Examples include accelerated atherosclerosis in patients after heart transplant or with underlying HIV infection, the number of days patients require ventilation after admission to intensive care units, the development of immunosenescence in the elderly and mortality in many groups of patients, including the general population. It is difficult to distinguish between CMV acting as causal contributor to such diverse pathology or simply having a benign bystander effect. However, recruitment of patients into placebo-controlled randomised trials of antiviral drugs with activity against CMV offers such a potential. This article describes the studies that have been conducted to date and emphasises that mortality after stem cell transplant (not attributed to CMV end-organ disease) has recently become the first proven indirect effect of CMV now that letermovir has significantly reduced non-relapse deaths. The implications for CMV vaccines are then discussed. Vaccines are already predicted to be highly cost-effective if they can reduce CMV end-organ disease. Health planners should now consider that cost effectiveness is likely to be enhanced further through reduction of the indirect effects of CMV. A prototype scheme for assessing this possibility is provided in order to stimulate discussion within the field. This article forms part of an online symposium on the prevention and therapy of DNA virus infections, dedicated to the memory of Mark Prichard.

Hemostasis in elderly patients with human immunodeficiency virus (HIV) infection-Cross-sectional study

Introduction: Aging and chronic HIV infection are clinical conditions that share the states of inflammation and hypercoagulability. The life expectancy of the world population has increased in the last decades, bringing as complications the occurrence of diseases that undergoing metabolic, bone, cardiological, vascular and neurological alterations. HIV-infected patients experience these changes early and are living longer due to the success of antiretroviral therapy. The objectives of this study was to evaluate some changes in the plasma hemostatic profile of 115 HIV-reactive elderly individuals over 60 years old in the chronic phase of infection, and compare with 88 healthy uninfected elderly individuals. Plasma determinations of D-dimers, Fibrinogen, von Willebrand Factor, Antithrombin, Prothrombin Time, Activated Partial Thromboplastin Time, and platelet count were performed. In the HIV-reactive group, these variables were analyzed according to viral load, protease inhibitor use and CD4⁺ T lymphocyte values. After adjusted values for age and sex, the results showed higher levels of Antithrombin (103%; 88%, p = 0.0001) and Prothrombin Time activities (92.4%; 88.2%, p = 0.019) in the HIV group compared to the control group. We observed higher values of Fibrinogen in protease inhibitor users in both the male (p = 0.043) and female (p = 0.004) groups, and in the female HIV group with detected viral load (p = 0.015). The male HIV group with a CD4⁺ count> 400 cells / mm³ presented higher von Willebrand Factor values (p = 0.036). D-Dimers had higher values in the older age groups (p = 0.003; p = 0.042, respectively). Conclusion: Our results suggest that the elderly with chronic HIV infection with few comorbidities had a better hemostatic profile than negative control group, reflecting the success of treatment. Protease inhibitor use and age punctually altered this profile.

Cardiac allograft vasculopathy: Insights on pathogenesis and therapy

Cardiac allograft vasculopathy (CAV) is a unique accelerated form of coronary vascular disease affecting heart transplant recipients. This complication is a significant contributor to medium- to long-term post-transplant morbidity and mortality. There is a high prevalence of CAV with approximately one in three patients developing CAV by 5 years post-transplant. Morphologically, CAV is characterized by concentric coronary intimal hyperplasia in both the epicardial arteries and intramural microvasculature. Although several immune and non-immune factors have been identified, their precise pathogenic mechanisms, interactions, and relative importance in the development of CAV are not well defined. The advent of improved imaging surveillance modalities has resulted in earlier detection during the disease process. However, overall management of CAV remains challenging due to paucity of treatment. This review aims to discuss key concepts on the pathogenesis of CAV and current management strategies, focusing on the use of mammalian target of rapamycin inhibitors.

Impaired Innate Immunity Mechanisms in the Brain of Alzheimer's Disease

Among environmental factors likely associated with Alzheimer's disease (AD), persistent virus infections, and age-related progressive decline of immune competence might play a pivotal role. However, AD antimicrobial brain immune responses are poorly investigated. The present study focused on genes involved in antimicrobial defenses, especially against virus infections, in the AD brain. In particular, mRNA levels of IRF7, MED23, IL28B, and IFN-α genes were analyzed in hippocampus and temporal cortex brain samples from AD and non-demented controls. All subjects were also genotyped for APOE ε, IRF7, MED23, and IL28B gene polymorphisms. Most AD patients showed decreased mRNA levels of all investigated genes in the hippocampus and temporal cortex. However, a small group of AD patients showed increased hippocampal mRNA expression of MED23, IL28B, and IFN-α. mRNA levels of MED23, IL28B, IFN-α from the hippocampus and those of MED23 from the temporal cortex were further decreased in APOE ε4 allele AD carriers. Moreover, rs6598008 polymorphism of IRF7 was significantly associated with decreased hippocampal expression of IRF7, MED23, IL28B, and IFN-α. These findings suggest that AD brains show impaired innate antimicrobial gene expression profiles, and individual genetic makeup, such as positivity for the APOE ε4 and IRF7 A alleles, might affect brain immune efficiency.

Clinical Course of Opportunistic Infections-Toxoplasmosis and Cytomegalovirus Infection in HIV-Infected Patients in Slovakia

: The HIV/acquired immunodeficiency syndrome (AIDS) pandemic has affected the health status of the population in many countries. Early symptomatic HIV infection includes persistent generalized lymphadenopathy (PGL), which can be associated with opportunistic infections, e.g., toxoplasmosis and Cytomegalovirus (CMV) infection. This study followed the occurrence of PGL, toxoplasmosis, and Cytomegalovirus infection in 32 HIV-positive patients and analyzed the clinical signs of disease in relation to the number of CD4 T lymphocytes. In monitored patients, the average number of CD4 T lymphocytes was 940.8 ± 396.7/µL of blood. Severe immunodeficiency was recorded in four persons, who also suffered from colitis and/or retinitis and pneumonitis. The number of CD4 T cells in patients with PGL was significantly lower than that in patients without lymphadenopathy. In 6 (18.8%) IgM and 11 (34.4%) IgG Toxoplasma gondii seropositive patients, the number of CD4 T lymphocytes was significantly lower than that in seronegative patients. The presence of IgM and IgG antibodies to Cytomegalovirus was recorded in all examined patients, and CMV infection clinically manifested in five persons. The occurrence of PGL, the higher viral load, and seropositivity to T. gondii were significantly related to decline in the CD4 T lymphocyte number. The clinical course of the diseases was influenced by the status of the patient's immunodeficiency and suggests ongoing immunosuppression and possible reactivation of both infections in all patients.

Peripheral Immunity, Immunoaging and Neuroinflammation in Parkinson's Disease

Parkinson's disease (PD) is the second most common neurodegenerative disorder among elderly population, characterized by the progressive degeneration of dopaminergic neurons in the midbrain. To date, exact cause remains unknown and the mechanism of neurons death uncertain. It is typically considered as a disease of central nervous system (CNS). Nevertheless, numerous evidence has been accumulated in several past years testifying undoubtedly about the principal role of neuroinflammation in progression of PD. Neuroinflammation is mainly associated with presence of activated microglia in brain and elevated levels of cytokine levels in CNS. Nevertheless, active participation of immune system as well has been noted, such as, elevated levels of cytokine levels in blood, the presence of auto antibodies, and the infiltration of T cell in CNS. Moreover, infiltration and reactivation of those T cells could exacerbate neuroinflammation to greater neurotoxic levels. Hence, peripheral inflammation is able to prime microglia into pro-inflammatory phenotype, which can trigger stronger response in CNS further perpetuating the on-going neurodegenerative process. In the present review, the interplay between neuroinflammation and the peripheral immune response in the pathobiology of PD will be discussed. First of all, an overview of regulation of microglial activation and neuroinflammation is summarized and discussed. Afterwards, we try to collectively analyze changes that occurs in peripheral immune system of PD patients, suggesting that these peripheral immune challenges can exacerbate the process of neuroinflammation and hence the symptoms of the disease. In the end, we summarize some of proposed immunotherapies for treatment of PD.

Increased frequency of CD4+CD57+ senescent T cells in patients with newly diagnosed acute heart failure: exploring new pathogenic mechanisms with clinical relevance

Recent animal studies showed T cells have a direct pathogenic role in the development of heart failure (HF). However, which subsets of T cells contribute to human HF pathogenesis and progression remains unclear. We characterized immunologic properties of various subsets of T cells and their clinical implications in human HF. Thirty-eight consecutive patients with newly diagnosed acute HF (21 males, mean age 66 ± 16 years) and 38 healthy control subjects (21 males, mean age 62 ± 12 years) were enrolled. We found that pro-inflammatory mediators, including CRP, IL-6 and IP-10 and the frequencies of CD57⁺ T cells in the CD4⁺ T cell population were significantly elevated in patients with acute HF compared to control subjects. A functional analysis of T cells from patients with acute HF revealed that the CD4⁺CD57⁺ T cell population exhibited a higher frequency of IFN-γ- and TNF-α- producing cells compared to the CD4⁺CD57⁻ T cell population. Furthermore, the frequency of CD4⁺CD57⁺ T cells at baseline and its elevation at the six-month follow-up were significantly related with the development of cardiovascular (CV) events, which were defined as CV mortality, cardiac transplantation, or rehospitalization due to HF exacerbation. In conclusion, CD4⁺CD57⁺ senescent T cells showed more inflammatory features and polyfunctionality and were associated with clinical outcome in patients with acute HF. More detailed study for senescent T cells might offer new opportunities for the prevention and treatment of human HF.

Inflammation as a mediator of arterial ageing

NEW FINDINGS

What is the topic of this review? This review summarizes and synthesizes what is known about the contribution of inflammation to age-related arterial dysfunction. What advances does it highlight? This review details observational evidence for the relationship of age-related inflammation and arterial dysfunction, insight from autoimmune inflammatory diseases and their effects on arterial function, interventional evidence linking inflammation and age-related arterial dysfunction, insight into age-related arterial inflammation from preclinical models and interventions to ameliorate age-related inflammation and arterial dysfunction.

ABSTRACT

Advanced age is a primary risk factor for cardiovascular disease, the leading cause of death in the industrialized world. Two major components of arterial ageing are stiffening of the large arteries and impaired endothelium-dependent dilatation in multiple vascular beds. These two alterations are major contributors to the development of overt cardiovascular disease. Increasing inflammation with advanced age is likely to play a role in this arterial dysfunction. The purpose of this review is to synthesize what is known about inflammation and its relationship to age-related arterial dysfunction. This review discusses both the initial observational evidence for the relationship of age-related inflammation and arterial dysfunction and the evidence that inflammatory autoimmune diseases are associated with a premature arterial ageing phenotype. We next discuss interventional and mechanistic evidence linking inflammation and age-related arterial dysfunction in older adults. We also attempt to summarize the relevant evidence from preclinical models. Lastly, we discuss interventions in both humans and animals that have been shown to ameliorate age-related arterial inflammation and dysfunction. The available evidence provides a strong basis for the role of inflammation in both large artery stiffening and impairment of endothelium-dependent dilatation; however, the specific inflammatory mediators, the initiating factors and the relative importance of the endothelium, smooth muscle cells, perivascular adipose tissue and immune cells in arterial inflammation are not well understood. With the expansion of the ageing population, ameliorating age-related arterial inflammation represents an important potential strategy for preserving vascular health in the elderly.

Church Attendance and CMV Herpes Virus Latency Among Bereaved and Non-Bereaved Adults

OBJECTIVE

There is widespread literature linking church attendance to physical health. However, little is known about the association of church attendance and the immune system, particularly during difficult life transitions. This study investigated the association between church attendance and CMV herpes-virus latency by assessing Cytomegalovirus (CMV) IgG antibody titers among bereaved and non-bereaved individuals.

METHODS

Participants included 44 bereaved individuals and 44 controls with a mean age of 68 (SD=12.84). CMV herpes-virus latency was measured using CMV IgG antibody titers. Church attendance was measured using three items from the Community Healthy Activities Model Program for Seniors (CHAMPS) Questionnaire.

RESULTS

After adjusting for participant's age, gender, education, minority status, weekly alcohol consumption, smoking, depression, body mass index (BMI) and comorbidities, church attendance was associated with lower CMV IgG antibody titers among bereaved and control participants. Further, there was a significant moderating effect of church attendance in the association between bereavement status and CMV IgG antibody titers, so that bereaved individuals attending church were found to have less herpes-virus reactivation (lower CMV IgG antibody titers) when compared to their bereaved counterparts that do not attend church.

CONCLUSION

This study demonstrated that church attendance is associated with less herpes-virus reactivation as indexed by lower levels of CMV IgG antibody titers, particularly among the bereaved. Future studies should focus on further understanding the pathways by which church attendance impacts CMV herpes-virus latency during stressful life events, such as bereavement.

Self-reported diabetes and herpes zoster are associated with a weak humoral response to the seasonal influenza A H1N1 vaccine antigen among the elderly

Background

The immune response to seasonal influenza vaccines decreases with advancing age. Therefore, an adjuvanted inactivated trivalent influenza vaccine (Fluad®) exists for elderly individuals. Fluad® is more immunogenic and efficacious than conventional influenza vaccines. However, the immune response varies and may still result in high frequencies of poor responders. Therefore, we aimed to a) examine the prevalence of a weak response to Fluad® and b) identify potential risk factors.

Methods

A prospective population-based study among individuals 65–80 years old was conducted in 2015/2016 in Hannover, Germany (n = 200). Hemagglutination-inhibition titers 21 days after vaccination with Fluad® served as indicator of vaccine responsiveness.

Results

The percentage of vaccinees with an inadequate vaccine response varied depending on the influenza strain: it was lowest for H3N2 (13.5%; 95% CI, 9.4–18.9%), intermediate for B strain (37.0%; 30.6–43.9%), and highest for H1N1 (49.0%; 42.2–55.9%). The risk of a weak response to the influenza A H1N1 strain was independently associated with self-reported diabetes (AOR, 4.64; 95% CI, 1.16–18.54), a history of herpes zoster (2.27; 1.01–5.10) and, to a much lesser extent, increasing age (change per year, 1.08; 0.99–1.16). In addition, herpes zoster was the only risk factor for a weak response to the H3N2 antigen (AOR, 3.12; 1.18–8.23). We found no significant association between sex, Body Mass Index, cancer, hypertension, heart attack and CMV seropositivity and a weak response to these two influenza A antigens. Despite its occurence in over one third of vaccinees, none of the variables examined proved to be risk factors for a weak response to the B antigen.

Conclusions

A considerable proportion of elderly individuals displayed a weak vaccine response to this adjuvanted seasonal influenza vaccine and further efforts are thus needed to improve immune responses to influenza vaccination among the elderly. Diabetes and herpes zoster were identified as potentially modifiable risk factors for a poor vaccine response against influenza A antigens, but the results also reveal the need for broader investigations to identify risk factors for inadequate responses to influenza B antigens.

Trial registration

No. NCT02362919 (ClinicalTrials.gov, date of registration: 09.02.2015).

Electronic supplementary material

The online version of this article (10.1186/s12879-019-4214-x) contains supplementary material, which is available to authorized users.

Host Genetics of Cytomegalovirus Pathogenesis

Human cytomegalovirus (HCMV) is a ubiquitous herpes virus (human herpes virus 5) with the highest morbidity and mortality rates compared to other herpes viruses. Risk groups include very young, elderly, transplant recipient, and immunocompromised individuals. HCMV may cause retinitis, encephalitis, hepatitis, esophagitis, colitis, pneumonia, neonatal infection sequelae, inflammatory, and age-related diseases. With an arsenal of genes in its large genome dedicated to host immune evasion, HCMV can block intrinsic cellular defenses and interfere with cellular immune responses. HCMV also encodes chemokines, chemokine receptors, and cytokines. Therefore, genes involved in human viral defense mechanisms and those encoding proteins targeted by the CMV proteins are candidates for host control of CMV infection and reactivation. Although still few in number, host genetic studies are producing valuable insights into biological processes involved in HCMV pathogenesis and HCMV-related diseases. For example, genetic variants in the immunoglobulin GM light chain can influence the antibody responsiveness to CMV glycoprotein B and modify risk of HCMV-related diseases. Moreover, CMV infection following organ transplantation has been associated with variants in genes encoding toll-like receptors (TLRs), programmed death-1 (PD-1), and interleukin-12p40 (IL-12B). A KIR haplotype (2DS4+) is proposed to be protective for CMV activation among hematopoietic stem cell transplant patients. Polymorphisms in the interferon lambda 3/4 (IFNL3/4) region are shown to influence susceptibility to CMV replication among solid organ transplant patients. Interestingly, the IFNL3/4 region is also associated with AIDS-related CMV retinitis susceptibility in HIV-infected patients. Likewise, interleukin-10 receptor 1 (IL-10R1) variants are shown to influence CMV retinitis development in patients with AIDS. Results from genome-wide association studies suggest a possible role for microtubule network and retinol metabolism in anti-CMV antibody response. Nevertheless, further genetic epidemiological studies with large cohorts, functional studies on the numerous HCMV genes, and immune response to chronic and latent states of infection that contribute to HCMV persistence are clearly necessary to elucidate the genetic mechanisms of CMV infection, reactivation, and pathogenesis.

The Immune System and Its Dysregulation with Aging

Aging leads to numerous changes that affect all physiological systems of the body including the immune system, causing greater susceptibility to infectious disease and contributing to the cardiovascular, metabolic, autoimmune, and neurodegenerative diseases of aging. The immune system is itself also influenced by age-associated changes occurring in such physiological systems as the endocrine, nervous, digestive, cardio-vascular and muscle-skeletal systems. This chapter describes the multidimensional effects of aging on the most important components of the immune system. It considers the age-related changes in immune cells and molecules of innate and adaptive immunity and consequent impairments in their ability to communicate with each other and with their aged environment. The contribution of age-related dysregulation of hematopoiesis, required for continuous replenishment of immune cells throughout life, is discussed in this context, as is the developmentally-programmed phenomenon of thymic involution that limits the output of naïve T cells and markedly contributes to differences between younger and older people in the distribution of peripheral blood T-cell types. How all these changes may contribute to low-grade inflammation, sometimes dubbed "inflammaging", is considered. Due to findings implicating elevated inflammatory immuno-mediators in age-associated chronic autoimmune and neurodegenerative processes, evidence for their possible contribution to neuroinflammation is reviewed.

Immunosenescence and Respiratory Infections Among Nursing Home Residents

Residents of nursing homes are at high risk of infectious complications due to respiratory infection. The nursing home setting places residents at high risk given the frequent contact among residents and by staff along with the possibility for continuous introduction of respiratory viruses from the community. Nursing home residents are among the most frail members of society. They have multiple comorbidities that can increase their risk of infection. Immunosenescence plays an important role in not only rendering these seniors susceptible in infection, particularly viral respiratory infection, but also interferes with protection. That is, the ability to mount a robust immune response to influenza and pneumococcal vaccine increase the risk. There have been a number of T cell deficits described in this population. CD4+ T cells, in particular T-regs and CMV-reactive CD4+ T cells, have been shown to be predictive of respiratory viral infection in this population. Although evidence exists that T cell subsets may correlate better with response to vaccine and protection, antibody responses to influenza vaccine remains an important correlate in this population. Large-scale epidemiologic studies are needed to establish better correlation between biomarkers for protection and respiratory and other pathogens that circulate in nursing homes.

Association between human herpes virus seropositivity and frailty in the elderly: A systematic review and meta-analysis

Frailty is an emerging geriatric syndrome characterized by decreased physiologic reserve and increased vulnerability to environmental factors. Several studies have examined the association between persistent cytomegalovirus (CMV) infection and poor clinical outcomes in the elderly, but the results are often contradictory. Here, we performed a systematic review and meta-analysis to analyze the association between human herpesvirus seropositivity [CMV, Epstein-Barr virus (EBV), Varicella zoster virus (VZV), and Herpes simplex virus (HSV)] and frailty in elderly people. Searches were performed in PubMed, SCOPUS, Lilacs, IBECS, and Web of Science databases. We used the odds ratio (OR) as a measure of the association between herpesvirus infections and frailty. Summary estimates were calculated using random-effects models. Six studies were included in the present systematic review. The data from 2559 elderly subjects were analyzed; 1571 of the subjects had ages between 60 and 79 years, and 988 of the subjects were older than 80. We found an association between CMV seropositivity and frailty in the elderly aged 60-79 years (OR 2.33, CI 95% 1.48-3.67) but not in the oldest-old subjects (OR 0.67, CI 95% 0.42-1.05). Moreover, no association was found between EBV, VZV, and HSV infections and frailty. Current evidence suggests an association between CMV seropositivity and frailty in individuals aged 60-79 years old.