Immunosenescence

Compositional analysis of lymphocytes and their relationship with health outcomes: findings from the health and retirement study

BACKGROUND

Immunosenescence, the gradual deterioration of the immune system, is critical for aging-related diseases. However, the lack of detailed population-level immune data has limited our understanding, underscoring the need for innovative analytical approaches. The Health and Retirement Study (HRS) in the United States provides a unique opportunity to examine T and B lymphocyte subsets using compositional data analysis and dimension reduction techniques.

METHODS

We constructed a hierarchical tree structure to map relationships among T and B subset cells in HRS. Network analysis examined conditional dependence across 16 immune subset cells, while stepwise redundancy analysis (SRDA) identified a subset of pairwise logratio measures that capture main variance in immune composition. We conducted two sets of supervised learning analyses: first, linear penalized log-contrast models to examine the associations between subset cells and three health outcomes (chronic disease index, self-reported health, and frailty level); second, linear regressions to examine the associations between the top selected logratios and health outcomes.

FINDINGS

Our study included 6,250 participants from the HRS with a median age of 68. Network analysis showed some dependence among 16 immune subset cells, including associations between central memory CD4 + T cells and both other CD4 + T cells and other lymphocytes, as well as between central memory CD8 + T cells and other CD8 + T cells. SRDA identified nine key log-ratio measures, explaining over 90% of the variance in immune composition. Linear penalized log-contrast models showed that a lower proportion of naïve CD4 + T cells and higher proportions of other CD4 + and central memory CD8 + T cells were significantly associated with greater chronic disease burden, poorer self-reported health, and higher frailty levels. Linear regression models using log-ratios reinforced these patterns, showing that a higher ratio of other lymphocytes over naïve CD4 + T cells and terminally differentiated effector memory CD4 + T cells over other CD8 + T cells were associated with greater chronic disease burden, poorer self-reported health, and higher frailty levels. In contrast, a higher ratio of other lymphocytes over central memory CD4 + T cells was associated with better health outcomes.

INTERPRETATION

Our findings highlight the value of a systems-based approach and compositional analysis in understanding immunosenescence and its impact on health. The identified subset cells and logratio measures provide meaningful insights into immune aging and warrant further investigation to explore their long-term relationships with health outcomes.

Herpesvirus Antibodies Are Correlated With Greater Expression of p16 in the T Cells of Humans

Background

There is an increasing awareness that aging of the immune system, or immunosenescence, is a key biological process underlying many of the hallmark diseases of aging and age-related decline broadly. While immunosenescence can be in part due to normal age-related changes in the immune system, emerging evidence posits that viral infections may be biological stressors of the immune system that accelerate the pace of immunosenescence.

Methods

We used a convenience sample of 42 individuals aged 65 years and older to examine correlations between antiviral immunoglobulin G (IgG) levels for 4 human herpesviruses (cytomegalovirus [CMV], herpes simplex virus [types 1 and 2], and Epstein-Barr virus) and multiple indicators of T-cell immunosenescence.

Results

We found that most of the sample (n = 33) was antiviral IgG positive for 2 or more of the 4 herpesvirus infections. We also examined correlations between both the total number of viruses for which an individual had antiviral IgG and each individual virus and multiple indicators of T-cell immunosenescence, particularly p16 expression. The strongest correlations were observed between the total number of viruses for which an individual had detectable antiviral IgG and p16 mean fluorescent intensity (MFI) among CD27-CD28-CD57+ CD4+ cells (r = 0.60; P < .001) and between anti-CMV IgG and p16 MFI of CD27-CD57+ CD4+ cells (r = 0.59; P < .001).

Conclusions

Broadly, our findings offer compelling preliminary evidence for future investigations to incorporate multiple indicators of persistent viral infections and a more comprehensive set of markers of T-cell immunosenescence in population-based studies of aging.

Multiple vaccine comparison in the same adults reveals vaccine-specific and age-related humoral response patterns: an open phase IV trial

Vaccine responsiveness is often reduced in older adults. Yet, our lack of understanding of low vaccine responsiveness hampers the development of effective vaccination strategies to reduce the impact of infectious diseases in the ageing population. Young-adult (25-49 y), middle-aged (50-64 y) and older-adult ( ≥ 65 y) participants of the VITAL clinical trials (n = 315, age-range: 28-98 y), were vaccinated with an annual (2019-2020) quadrivalent influenza (QIV) booster vaccine, followed by a primary 13-valent pneumococcal-conjugate (PCV13) vaccine (summer/autumn 2020) and a primary series of two SARS-CoV-2 mRNA-1273 vaccines (spring 2021). This unique setup allowed investigation of humoral responsiveness towards multiple vaccines within the same individuals over the adult age-range. Booster QIV vaccination induced comparable H3N2 hemagglutination inhibition (HI) titers in all age groups, whereas primary PCV13 and mRNA-1273 vaccination induced lower antibody concentrations in older as compared to younger adults (primary endpoint). The persistence of humoral responses, towards the 6 months timepoint, was shorter in older adults for all vaccines (secondary endpoint). Interestingly, highly variable vaccine responder profiles overarching multiple vaccines were observed. Yet, approximately 10% of participants, mainly comprising of older male adults, were classified as low responders to multiple vaccines. This study aids the identification of risk groups for low vaccine responsiveness and hence supports targeted vaccination strategies. Trial number: NL69701.041.19, EudraCT: 2019-000836-24.

Age-Related Clusters and Favorable Immune Phenotypes in Young Breast Cancer Patients

Breast cancer (BC) patients aged <40 years at diagnosis experience aggressive disease and poorer survival compared with women diagnosed with BC at 40 to 49 years, but the age-related biology is described to little extent. Here, we explored transcriptional alterations in BC to gain better understanding of age-related tumor biology. We studied a subset of the Bergen in-house cohort (n = 127; age range, 26-49 years) and used the NanoString Breast Cancer 360 expression panel on formalin-fixed paraffin-embedded BC tissue, and publicly available global BC messenger RNA expression data (n = 204; age range, 22-49 years), to explore differentially expressed genes between the young (age <40 years) and older (age 40-49 years) patients. Unsupervised hierarchical clustering was applied to identify gene expression-based patient clusters. We applied established computational approaches to define the PAM50 subtypes, risk of recurrence scores (ROR), and risk groups and to infer the proportions of 22 immune cell types from bulk gene expression profiles of patients aged <50 years at BC diagnosis. Differentially expressed genes and gene sets were investigated using OncoEnrichR and g:Profiler to describe functional profiles and pathway enrichment. We identified 4 age-related patient clusters presenting distinct characteristics of PAM50 subtypes and ROR profiles, which demonstrated independent prognostic value when adjusted for traditional clinicopathologic variables and the known molecular subtypes. Our findings showed better survival than expected in the basal-enriched cluster 2 and in triple-negative and basal-like BC. Deconvolution analyses of immunophenotypes indicated higher levels of M0 and M1 macrophages than M2 macrophages in subsets of young BC. Our approach identifies age-based patient clusters with distinct clinicopathologic profiles, to a large extent overlapping with the PAM50 subtypes, although with independent prognostic values in multivariate survival analyses. The patient clusters provided new insight in the immune cell distribution across tumor subtypes, potentially contributing to survival differences between the clusters and the molecular subtypes and indicating age-related mechanisms improving outcome. Our study confirms the applicability of ROR as a valid prognosticator also in a young BC cohort.

The embodiment of the neighborhood socioeconomic environment in the architecture of the immune system

There is growing recognition of the importance of immune health for understanding the origins of ageing-related disease and decline. Numerous studies have demonstrated consistent associations between the social determinants of health and immunosenescence (i.e. ageing of the immune system). Yet few studies have interrogated the relationship between neighborhood socioeconomic status (nSES) and biologically specific measures of immunosenescence. We used data from the US Health and Retirement Study to measure immunosenescence linked with neighborhood socioeconomic data from the National Neighborhood Data Archive to examine associations between indicators of nSES and immunosenescence. We found associations between both the ratio of terminally differentiated effector memory to naïve (EMRA:Naïve) CD4+ T cells and cytomegalovirus (CMV) immunoglobulin G (IgG) levels and nSES. For the CD4+ EMRA:Naïve ratio, each 1% increase in the neighborhood disadvantage index was associated with a 0.005 standard deviation higher value of the EMRA:Naïve ratio (95% CI: 0.0003, 0.01) indicating that living in a neighborhood that is 10% higher in disadvantage is associated with a 0.05 higher standardized value of the CD4+ EMRA:Naïve ratio. The results were fully attenuated when adjusting for both individual-level SES and race/ethnicity. For CMV IgG antibodies, a 1% increase in neighborhood disadvantage was associated a 0.03 standard deviation higher value of CMV IgG antibodies (β = 0.03; 95% CI: 0.002, 0.03) indicating that living in a neighborhood that is 10% higher in disadvantage is associated with a 0.3 higher standardized value of CMV. This association was attenuated though still statistically significant when controlling for individual-level SES and race/ethnicity. The findings from this study provide compelling initial evidence that large, nonspecific social exposures, such as neighborhood socioeconomic conditions, can become embodied in cellular processes of immune ageing.

Peripheral immune function and Alzheimer's disease: a living systematic review and critical appraisal

BACKGROUND

A growing body of literature examines the relationship between peripheral immune function and Alzheimer's Disease (AD) in human populations. Our living systematic review summarizes the characteristics and findings of these studies, appraises their quality, and formulates recommendations for future research.

METHODS

We searched the electronic databases PubMed, PsycINFO, and Web of Science, and reviewed references of previous reviews and meta-analyses to identify human studies examining the relationship between any peripheral immune biomarkers and AD up to September 7th, 2023. We examined patterns of reported statistical associations (positive, negative, and null) between each biomarker and AD across studies. Evidence for each biomarker was categorized into four groups based on the proportion of studies reporting different associations: corroborating a positive association with AD, a negative association, a null association, and presenting contradictory findings. A modified Newcastle-Ottawa scale (NOS) was employed to assess the quality of the included studies.

FINDINGS

In total, 286 studies were included in this review. The majority were cross-sectional (n = 245, 85.7%) and hospital-based (n = 248, 86.7%), examining relationships between 187 different peripheral immune biomarkers and AD. Cytokines were the most frequently studied group of peripheral immune biomarkers. Evidence supported a positive association with AD for six biomarkers, including IL-6, IL-1β, IFN-γ, ACT, IL-18, and IL-12, and a negative association for two biomarkers, including lymphocytes and IL-6R. Only a small proportion of included studies (n = 22, 7.7%) were deemed to be of high quality based on quality assessment.

INTERPRETATION

Existing research on peripheral immune function and AD exhibits substantial methodological variations and limitations, with a notable lack of longitudinal, population-based studies investigating a broad range of biomarkers with prospective AD outcomes. The extent and manner in which peripheral immune function can contribute to AD pathophysiology remain open questions. Given the biomarkers that we identified to be associated with AD, we posit that targeting peripheral immune dysregulation may present a promising intervention point to reduce the burden of AD.

The Interplay Between the Immune System, Tumor Suppressor Genes, and Immune Senescence in Mesothelioma Development and Response to Immunotherapy

Despite efforts to ban asbestos mining and manufacturing, mesothelioma deaths in the United States have remained stable at approximately 2500 cases annually. This trend is not unique to the United States but is also a global phenomenon, associated with increased aging of populations worldwide. Although geoeconomic factors such as lack of regulations and continued asbestos manufacturing in resource-poor countries play a role, it is essential to consider biological factors such as immune senescence and increased genetic instability associated with aging. Recognizing that mesothelioma shares genetic instability and immune system effects with other age-related cancers is crucial because the impact of aging on mesothelioma is frequently assessed in the context of disease latency after asbestos exposure. Nevertheless, the long latency period, often cited as a reason for mesothelioma's elderly predominance, should not overshadow the shared mechanisms. This communication focuses on the role of immune surveillance in mesothelioma, particularly exploring the impact of immune escape resulting from altered TSG function during aging, contributing to the phylogenetic development of gene mutations and mesothelioma oncogenesis. The interplay between the immune system, TSGs, and aging not only shapes the immune landscape in mesothelioma but also contributes to the development of heterogeneous tumor microenvironments, significantly influencing responses to immunotherapy approaches and survival rates. By understanding the complex interplay between aging, TSG decline, and immune senescence, health care professionals can pave the way for more effective and personalized immunotherapies, ultimately offering hope for better outcomes in the fight against mesothelioma.

The interplay between obesity, immunosenescence, and insulin resistance

Obesity, which is the accumulation of fat in adipose tissue, has adverse impacts on human health. Obesity-related metabolic dysregulation has similarities to the metabolic alterations observed in aging. It has been shown that the adipocytes of obese individuals undergo cellular aging, known as senescence. Senescence can be transmitted to other normal cells through a series of chemical factors referred to as the senescence-associated secretory phenotype (SASP). Most of these factors are pro-inflammatory compounds. The immune system removes these senescent T-cells, but immunosenescence, which is the senescence of immune cells, disrupts the clearance of senescent T-cells. Immunosenescence occurs as a result of aging or indirectly through transmission from senescent tissues. The significant occurrence of senescence in obesity is expected to cause immunosenescence and impairs the immune response to resolve inflammation. The sustained and chronic inflammation disrupts insulin's metabolic actions in metabolic tissues. Therefore, this review focuses on the role of senescent adipocyte cells in obesity-associated immunosenescence and subsequent metabolic dysregulation. Moreover, the article suggests novel therapeutic approaches to improve metabolic syndrome by targeting senescent T-cells or using senotherapeutics.

Tuberculosis and COVID-19 in the elderly: factors driving a higher burden of disease

Mycobacterium tuberculosis (M.tb) and SARS-CoV-2 are both infections that can lead to severe disease in the lower lung. However, these two infections are caused by very different pathogens (Mycobacterium vs. virus), they have different mechanisms of pathogenesis and immune response, and differ in how long the infection lasts. Despite the differences, SARS-CoV-2 and M.tb share a common feature, which is also frequently observed in other respiratory infections: the burden of disease in the elderly is greater. Here, we discuss possible reasons for the higher burden in older adults, including the effect of co-morbidities, deterioration of the lung environment, auto-immunity, and a reduced antibody response. While the answer is likely to be multifactorial, understanding the main drivers across different infections may allow us to design broader interventions that increase the health-span of older people.

When GETomics meets aging and exercise in COPD

The term GETomics has been recently proposed to illustrate that human health and disease are actually the final outcome of many dynamic, interacting and cumulative gene (G) - environment (E) interactions that occur through the lifetime (T) of the individual. According to this new paradigm, the final outcome of any GxE interactions depends on both the age of the individual at which such GxE interaction occurs as well as on the previous, cumulative history of previous GxE interactions through the induction of epigenetic changes and immune memory (both lasting overtime). Following this conceptual approach, our understanding of the pathogenesis of chronic obstructive pulmonary disease (COPD) has changed dramatically. Traditionally believed to be a self-inflicted disease induced by tobacco smoking occurring in older men and characterized by an accelerated decline of lung function with age, now we understand that there are many other risk factors associated with COPD, that it occurs also in females and young individuals, that there are different lung function trajectories through life, and that COPD is not always characterized by accelerated lung function decline. In this paper we discuss how a GETomics approach to COPD may open new perspectives to better understand its relationship with exercise limitation and the ageing process.

Ageing and the Autonomic Nervous System

The vertebrate nervous system is divided into central (CNS) and peripheral (PNS) components. In turn, the PNS is divided into the autonomic (ANS) and enteric (ENS) nervous systems. Ageing implicates time-related changes to anatomy and physiology in reducing organismal fitness. In the case of the CNS, there exists substantial experimental evidence of the effects of age on individual neuronal and glial function. Although many such changes have yet to be experimentally observed in the PNS, there is considerable evidence of the role of ageing in the decline of ANS function over time. As such, this chapter will argue that the ANS constitutes a paradigm for the physiological consequences of ageing, as well as for their clinical implications.

Socioeconomic and race/ethnic differences in immunosenescence: Evidence from the Health and Retirement Study

BACKGROUND

The COVID-19 pandemic has highlighted the urgent need to understand variation in immunosenescence at the population-level. Thus far, population patterns of immunosenescence have not well described.

METHODS

We characterized measures of immunosenescence from the 2016 Venous Blood Study from the nationally representative U.S Health and Retirement Study (HRS) of individuals ages 50 years and older.

RESULTS

Median values of the CD8+:CD4+, EMRA:Naïve CD4+ and EMRA:Naïve CD8+ ratios were higher among older participants and were lower in those with additional educational attainment. Generally, minoritized race and ethnic groups had immune markers suggestive of a more aged immune profile: Hispanics had a CD8+:CD4+ median value of 0.37 (95 % CI: 0.35, 0.39) compared to 0.30 in non-Hispanic Whites (95 % CI: 0.29, 0.31). Non-Hispanic Blacks had the highest median value of the EMRA:Naïve CD4+ ratio (0.08; 95 % CI: 0.07, 0.09) compared to non-Hispanic Whites (0.03; 95 % CI: 0.028, 0.033). In regression analyses, race/ethnicity and education were associated with large differences in the immune ratio measures after adjustment for age and sex.

CONCLUSIONS

Lower educational attainment and minoritized racial ethnic status were associated with higher levels of immunosenescence. This population variation may have important implications for both risk of age-related disease and vulnerability to emerging pathogens (e.g., SARS-CoV-2).

Comparisons of Metastatic Patterns, Survival Outcomes and Tumor Immune Microenvironment Between Young and Non-Young Breast Cancer Patients

Background: Metastases are the main cause of breast cancer-related deaths. Breast cancer has a more aggressive phenotype and less favorable prognosis in young females than in older females. In this study, we aimed to compare the metastatic patterns, survival outcomes and tumor immune microenvironment of young and non-young breast cancer patients.

Methods: Patients with a diagnosis of breast cancer were identified from the Surveillance, Epidemiology, and End Results (SEER) database between 2010 and 2015. The significance of young age (≤40 years) in the metastatic profile and prognosis of breast cancer was investigated. The transciptome expression data were acquired from The Cancer Genome Atlas (TCGA) database. And the differentially expressed genes (DEGs) and primarily enriched function pathways were identified by comparing between young and non-young breast cancer samples, and tumor immune infiltrating cell types in the tumor microenvironment were compared.

Results: A total of 281,829 female breast cancer patients were included in SEER: 18,331 young (6.5%) and 263,498 non-young (93.5%) women. The metastatic rates of bone, liver and distant lymph nodes (DLNs) in the young cohort were significantly higher than those in the non-young cohort. The most frequent two-site metastatic combination was bone and liver (0.61%) in the young cohort, whereas it was bone and lung (0.32%) in the non-young cohort. Breast cancer-specific survival (BCSS) was significantly shortened among those in the young cohort compared with those in the non-young cohort (p &lt; 0.001). Young age was associated with significantly shorter BCSS only among patients with HR+/HER2- tumors (p &lt; 0.001). The enriched biological pathways based on DEGs between two cohorts were related to the regulation of immune response and several metabolic processes. M2 macrophages were significantly abundant in non-young breast cancer than young breast cancer.

Conclusion: Young and non-young breast cancer patients present with different metastatic patterns. Young age is a negative prognostic factor, particularly for HR+/HER2- breast cancer. The differences in metastatic patterns between young and non-young cohorts should be taken into account in the clinical management of metastatic breast cancer. The young breast cancer patients may gain better response to immunotherapy due to immune activated TME than non-young breast cancer.

Aging Leads to Increased Monocytes and Macrophages With Altered CSF-1 Receptor Expression and Earlier Tumor-Associated Macrophage Expansion in Murine Mesothelioma

Increased cancer incidence occurs with the emergence of immunosenescence, highlighting the indispensability of the immune system in preventing cancer and its dysregulation with aging. Tumor-associated macrophages (TAMs) are often present in high numbers and are associated with poor clinical outcomes in solid cancers, including mesothelioma. Monocytes and macrophages from the bone marrow and spleen can respond to tumor-derived factors, such as CSF-1, and initiation of the CSF-1R signaling cascade results in their proliferation, differentiation, and migration to the tumor. Age-related changes occur in monocytes and macrophages in terms of numbers and function, which in turn can impact tumor initiation and progression. Whether this is due to changes in CSF-1R expression with aging is currently unknown and was investigated in this study. We examined monocytes and macrophages in the bone marrow and spleen during healthy aging in young (3–4 months) and elderly (20–24 months) female C57BL/6J mice. Additionally, changes to these tissues and in TAMs were examined during AE17 mesothelioma tumor growth. Healthy aging resulted in an expansion of Ly6C^high monocytes and macrophages in the bone marrow and spleen. CSF-1R expression levels were reduced in elderly splenic macrophages only, suggesting differences in CSF-1R signaling between both cell type and tissue site. In tumor-bearing mice, Ly6C^high monocytes increased with tumor growth in the spleen in the elderly and increased intracellular CSF-1R expression occurred in bone marrow Ly6C^high monocytes in elderly mice bearing large tumors. Age-related changes to bone marrow and splenic Ly6C^high monocytes were reflected in the tumor, where we observed increased Ly6C^high TAMs earlier and expansion of Ly6C^low TAMs later during AE17 tumor growth in the elderly compared to young mice. F4/80^high TAMs increased with tumor growth in both young and elderly mice and were the largest subset of TAMs in the tumor. Together, this suggests there may be a faster transition of Ly6C^high towards F4/80^high TAMs with aging. Amongst TAM subsets, expression of CSF-1R was lowest in F4/80^high TAMs, however Ly6C^low TAMs had higher intracellular CSF-1R expression. This suggests downstream CSF-1R signaling may vary between macrophage subsets, which can have implications towards CSF-1R blockade therapies targeting macrophages in cancer.

Efficacy of Disease Modifying Therapies in Progressive MS and How Immune Senescence May Explain Their Failure

The advent of disease modifying therapies (DMT) in the past two decades has been the cornerstone of successful clinical management of multiple sclerosis (MS). Despite the great strides made in reducing the relapse frequency and occurrence of new signal changes on neuroimaging in patients with relapsing remitting MS (RRMS) by approved DMT, it has been challenging to demonstrate their effectiveness in non-active secondary progressive MS (SPMS) and primary progressive MS (PPMS) disease phenotypes. The dichotomy of DMT effectiveness between RRMS and progressive MS informs on distinct pathogeneses of the different MS phenotypes. Conversely, factors that render patients with progressive MS resistant to therapy are not understood. Thus far, age has emerged as the main correlate of the transition from RRMS to SPMS. Whether it is aging and age-related factors or the underlying immune senescence that qualitatively alter immune responses as the disease transitions to SPMS, that diminish DMT effectiveness, or both, is currently not known. Here, we will discuss the role of immune senescence on different arms of the immune system, and how it may explain relative DMT resistance.

Sociodemographic Differences in Population-Level Immunosenescence in Older Age

Background

The COVID-19 pandemic has highlighted the urgent need to understand variation in immunosenescence at the population-level. Thus far, population patterns of immunosenescence are not well described.

Methods

We characterized measures of immunosenescence from newly released venous blood data from the nationally representative U.S Health and Retirement Study (HRS) of individuals ages 56 years and older.

Findings

Median values of the CD8+:CD4+, EMRA:Nave CD4+ and EMRA:Nave CD8+ ratios were higher among older participants and were lower in those with additional educational attainment. Generally, minoritized race and ethnic groups had immune markers suggestive of a more aged immune profile: Hispanics had a CD8+:CD4+ median value of 0.37 (95% CI: 0.35, 0.39) compared to 0.30 in Whites (95% CI: 0.29, 0.31). Blacks had the highest median value of the EMRA:Nave CD4+ ratio (0.08; 95% CI: 0.07, 0.09) compared to Whites (0.03; 95% CI: 0.028, 0.033). In regression analyses, race/ethnicity and education were associated with large differences in the immune ratio measures after adjustment for age and sex. For example, each additional level of education was associated with roughly an additional decade of immunological age, and the racial/ethnic differences were associated with two to four decades of additional immunological age.

Interpretation

Our study provides novel insights into population variation in immunosenescence. This has implications for both risk of age-related disease and vulnerability to novel pathogens (e.g., SARS-CoV-2).

Funding

This study was partially funded by the U.S. National Institutes of Health, National Institute on Aging R00AG062749. AEA and GAN acknowledge support from the National Institutes of Health, National Institute on Aging R01AG075719. JBD acknowledges support from the Leverhulme Trust (Centre Grant) and the European Research Council grant ERC-2021-CoG-101002587.

Research in context

Evidence before this study: Alterations in immunity with chronological aging have been consistently demonstrated across human populations. Some of the hallmark changes in adaptive immunity associated with aging, termed immunosenescence, include a decrease in nave T-cells, an increase in terminal effector memory cells, and an inverted CD8:CD4 T cell ratio. Several studies have shown that social and psychosocial exposures can alter aspects of immunity and lead to increased susceptibility to infectious diseases.Add value of this study: While chronological age is known to impact immunosenescence, there are no studies examining whether social and demographic factors independently impact immunosenescence. This is important because immunosenescence has been associated with greater susceptibility to disease and lower immune response to vaccination. Identifying social and demographic variability in immunosenescence could help inform risk and surveillance efforts for preventing disease in older age. To our knowledge, we present one of the first large-scale population-based investigations of the social and demographic patterns of immunosenescence among individuals ages 50 and older living in the US. We found differences in the measures of immunosenescence by age, sex, race/ethnicity, and education, though the magnitude of these differences varied across immune measures and sociodemographic subgroup. Those occupying more disadvantaged societal positions (i.e., minoritized race and ethnic groups and individuals with lower educational attainment) experience greater levels of immunosenescence compared to those in less disadvantaged positions. Of note, the magnitude of effect of sociodemographic factors was larger than chronological age for many of the associations.Implications for practice or policy and future research: The COVID-19 pandemic has highlighted the need to better understand variation in adaptive and innate immunity at the population-level. While chronological age has traditionally been thought of as the primary driver of immunological aging, the magnitude of differences we observed by sociodemographic factors suggests an important role for the social environment in the aging human immune system.

Single-cell profiling of immune system alterations in lymphoid, barrier and solid tissues in aged mice

Aging exerts profound and paradoxical effects on the immune system, at once impairing proliferation, cytotoxicity and phagocytosis, and inducing chronic inflammation. Previous studies have focused on individual tissues or cell types, while a comprehensive multisystem study of tissue-resident and circulating immune populations during aging is lacking. Here we reveal an atlas of age-related changes in the abundance and phenotype of immune cell populations across 12 mouse tissues. Using cytometry-based high parametric analysis of 37 mass-cytometry and 55 spectral flow-cytometry parameters, mapping samples from young and aged animals revealed conserved and tissue-type-specific patterns of both immune atrophy and expansion. We uncovered clear phenotypic changes in both lymphoid and myeloid lineages in aged mice, and in particular a contraction in natural killer cells and plasmacytoid dendritic cells. These changes correlated with a skewing towards myelopoiesis at the expense of early lymphocyte genesis in aged mice. Taken together, this atlas represents a comprehensive, systematic and thorough resource of the age-dependent alterations of the mammalian immune system in lymphoid, barrier and solid tissues.

Molecular and cellular pathways contributing to brain aging

Aging is the leading risk factor for several age-associated diseases such as neurodegenerative diseases. Understanding the biology of aging mechanisms is essential to the pursuit of brain health. In this regard, brain aging is defined by a gradual decrease in neurophysiological functions, impaired adaptive neuroplasticity, dysregulation of neuronal Ca2+ homeostasis, neuroinflammation, and oxidatively modified molecules and organelles. Numerous pathways lead to brain aging, including increased oxidative stress, inflammation, disturbances in energy metabolism such as deregulated autophagy, mitochondrial dysfunction, and IGF-1, mTOR, ROS, AMPK, SIRTs, and p53 as central modulators of the metabolic control, connecting aging to the pathways, which lead to neurodegenerative disorders. Also, calorie restriction (CR), physical exercise, and mental activities can extend lifespan and increase nervous system resistance to age-associated neurodegenerative diseases. The neuroprotective effect of CR involves increased protection against ROS generation, maintenance of cellular Ca2+ homeostasis, and inhibition of apoptosis. The recent evidence about the modem molecular and cellular methods in neurobiology to brain aging is exhibiting a significant potential in brain cells for adaptation to aging and resistance to neurodegenerative disorders.

Immunosurveillance of Cancer and Viral Infections with Regard to Alterations of Human NK Cells Originating from Lifestyle and Aging

Natural killer (NK) cells are cytotoxic immune cells with an innate capacity for eliminating cancer cells and virus- infected cells. NK cells are critical effector cells in the immunosurveillance of cancer and viral infections. Patients with low NK cell activity or NK cell deficiencies are predisposed to increased risks of cancer and severe viral infections. However, functional alterations of human NK cells are associated with lifestyles and aging. Personal lifestyles, such as cigarette smoking, alcohol consumption, stress, obesity, and aging are correlated with NK cell dysfunction, whereas adequate sleep, moderate exercise, forest bathing, and listening to music are associated with functional healthy NK cells. Therefore, adherence to a healthy lifestyle is essential and will be favorable for immunosurveillance of cancer and viral infections with healthy NK cells.

Age-Specific Imbalance of Circulating Tfh Cell Subsets and Its Association With Gout-Targeted Kidney Impairment

Objective

Gout is a chronic disease characterized by the deposition of monosodium urate (MSU) crystals in tissue. Study with a focus on adaptive immune response remains to be understood although innate immune response has been reported extensively in gout etiology. Our study attempted to investigate the association of gout-related immune cell imbalance with clinical features and comorbidity with renal impairment and the implicated pathogenesis via the assessment of T and B cell subsets in different activity phases or with immune effects combined with the analyses of clinical parameters.

Methods

Fifty-eight gout patients and 56 age- and sex-matched healthy individuals were enrolled. To learn the roles of circulating T cells, a lymphocyte profile incorporating 32 T cell subsets was tested from isolated freshly peripheral blood monocyte cells (PBMCs) with multiple-color flow cytometry. Furthermore, the collected clinical features of participants were used to analyze the characteristics of these differential cell subsets. Stratified on the basis of the level of creatinine (Cr, enzymatic method), all patients were categorized into Cr^low (Cr ≤ 116 μmol/L) and Cr^hi (Cr > 116 μmol/L) groups to exploit whether these gout-associated T cell subsets were functional in gout-targeted kidney dysfunction. The differentiation of B cells was investigated in gout patients.

Results

Our results show that CD 4⁺ T cells, Th2 cells, and Tc2 cells were upregulated, whereas Tc17 cells were downregulated. Tfh cells skewed toward the polarization of Tfh2 cells. Specifically, Tfh2 cells increased, but Tfh1 cells decreased, accompanied with aging for gout patients, suggesting that age might trigger the skewing of Tfh1/Tfh2 cell subsets to influence gout development. Moreover, Tfh2 cells were connected to renal dysfunction as well. No alterations of B cell subsets were observed in patients when compared to controls.

Conclusions

Our data demonstrate age-specific dysfunctions of Tfh1/2 cells in gout occurrence, and Tfh2 cell upregulation is associated with gout-targeted renal dysfunction. However, Tfh2 cells may function in auto-inflammatory gout independent of helping B differentiation, and an in-depth study remains to be conducted.

[Specificity of the management of metastatic renal cancer in the older patient]

AIM

To define the necessary arrangements of medical treatment with anti-angiogenics, mTOR inhibitor or systemic immunotherapies in the management of metastatic renal cell carcinoma in elderly patients.

METHOD

Bibliographical search was performed from the Medline bibliographic database (NLM Pubmed tool) and Embase focused on: metastatic renal cell carcinoma, elderly, treatment.

RESULTS

The selection criteria for the medical treatment of metastatic renal cell carcinoma in elderly patients are the IMDC score, necessarily complemented by performance status, the tolerability profile of treatments, more frequent drug interactions, treatment adherence, management capacity of side effects, and patient preference. Each of these criteria is detailed in critical ways.

CONCLUSION

The efficacy and tolerability of medical treatments for metastatic renal cancer have not been reported as different depending on age. No dosage adjustment is recommended in principle. However, prevention and early treatment of side effects of treatment should be strengthened in elderly patients.

Moderate levels of physical fitness maintain telomere length in non-senescent T CD8+ cells of aged men

OBJECTIVES

Immunosenescence is an age-associated change characterized by a decreased immune response. Although physical activity has been described as fundamental for maintaining the quality of life, few studies have evaluated the effects of different levels of exercise on telomere length in aged populations. The present study aimed to analyze the effects of different levels of physical activity, classified by the Maximal oxygen consumption (VO2 max) values, on the telomere length of memory Cluster of differentiation (CD) CD4+(CD45ROneg and CD45RO+), effector CD8+CD28neg, and CD8+CD28+ T cells in aged individuals.

METHODS

Fifty-three healthy elderly men (aged 65-85 years) were included in this study. Their fitness level was classified according to the American College of Sports Medicine (ACSM) for VO2 max (mL/kg/min). Blood samples were obtained from all participants to analyze the percentage of CD3, CD4, CD8, CD28+, naïve, and subpopulations of memory T cells by using flow cytometry. Furthermore, using the Flow-FISH methodology, the CD4+CD45RO+, CD4+CD45ROneg, CD8+CD28+, and CD8+CD28negT cell telomere lengths were measured.

RESULTS

There was a greater proportion of effector memory T CD4+ cells and longer telomeres in CD8+CD28+ T cells in the moderate physical fitness group than in the other groups. There was a higher proportion of terminally differentiated memory effector T cells in the low physical fitness group.

CONCLUSION

A moderate physical activity may positively influence the telomere shortening of CD28+CD8+T cells. However, additional studies are necessary to evaluate the importance of this finding with regard to immune function responses in older men.

Immune cell concentrations among the primary tumor microenvironment in colorectal cancer patients predicted by clinicopathologic characteristics and blood indexes

Background

Immune cells play a key role in cancer progression and treatment. It is unclear whether the clinicopathologic characteristics and blood indexes of colorectal cancer (CRC) patients could predict immune cell concentrations in the tumor microenvironment.

Methods

CRC patients with detailed data and tumor tissue who visited Sun Yat-sen University Cancer Center between April 1, 2004, and September 1, 2017, were enrolled. The densities of CD3+ and CD8+ T cells examined by immunohistochemistry in both the core of the tumor (CT) and the invasive margin (IM) were summed as the Immunoscore. The relationships between the Immunoscore and clinicopathologic characteristics and blood indexes, including tumor biomarkers (carcinoembryonic antigen (CEA) and carbohydrate antigen 19–9 (CA 19–9)), inflammatory markers (lactate dehydrogenase (LDH), C-reactive protein (CRP), albumin (ALB), neutrophils, lymphocytes, monocytes, platelets, NLR (neutrophil-to-lymphocyte ratio), PLR (platelet-to-lymphocyte ratio) and LMR (lymphocyte-to-monocyte ratio)) and lipid metabolism markers (cholesterol (CHO), triglyceride (TG), high-density lipoprotein (HDL), low-density lipoprotein (LDL), apolipoprotein A1 (ApoA1), and apolipoprotein B (ApoB)), were analyzed using SPSS.

Results

Older patients had lower CD3+ and CD8+ T cell expression in the IM and a lower Immunoscore than did younger patients. CD8+ T cell expression in the IM and the Immunoscore were lower in right-side tumors than in left-sided tumors. High CD8+ T cell expression in the CT was found in the T4 stage group. The higher the CEA level in the blood, the fewer CD8+ T cells were in the CT. Either fewer monocytes or a higher LMR in the blood, the larger number of CD3+ T cells in the CT. The more ApoA1 was in the blood, the more CD3+ T cells were in both the CT and the IM.

Conclusion

Age, T stage, tumor location, CEA, monocytes, LMR and ApoA1 could reflect immune cells infiltrating the tumor microenvironment of CRC.

Macrophage Depletion in Elderly Mice Improves Response to Tumor Immunotherapy, Increases Anti-tumor T Cell Activity and Reduces Treatment-Induced Cachexia

Most cancers emerge in the elderly, including lung cancer and mesothelioma, yet the elderly remain an underrepresented population in pre-clinical cancer studies and clinical trials. The immune system plays a critical role in the effectiveness of many anti-cancer therapies in young hosts via tumor-specific T cells. However, immunosuppressive macrophages can constitute up to 50% of the tumor burden and impair anti-tumor T cell activity. Altered macrophage phenotype and function during aging may further impact anti-tumor T cell responses. Yet, the impact of macrophages on anti-tumor T cell responses and immunotherapy in the elderly is unknown. Therefore, we examined macrophages and their interaction with T cells in young (3 months) and elderly (20-24 months) AE17 mesothelioma-bearing female C57BL/6J mice during tumor growth. Mesothelioma tumors grew faster in elderly compared with young mice, and this corresponded with an increase in tumor-associated macrophages. During healthy aging, macrophages increase in bone marrow and spleens suggesting that these sites have an increased potential to supply cancer-promoting macrophages. Interestingly, in tumor-bearing mice, bone marrow macrophages increased proliferation whilst splenic macrophages had reduced proliferation in elderly compared with young mice, and macrophage depletion using the F4/80 antibody slowed tumor growth in young and elderly mice. We also examined responses to treatment with intra-tumoral IL-2/anti-CD40 antibody immunotherapy and found it was less effective in elderly (38% tumor regression) compared to young mice (90% regression). Tumor-bearing elderly mice decreased in vivo anti-tumor cytotoxic T cell activity in tumor draining lymph nodes and spleens. Depletion of macrophages using F4/80 antibody in elderly, but not young mice, improved IL-2/anti-CD40 immunotherapy up to 78% tumor regression. Macrophage depletion also increased in vivo anti-tumor T cell activity in elderly, but not young mice. All the tumor-bearing elderly (but not young) mice had decreased body weight (i.e., exhibited cachexia), which was greatly exacerbated by immunotherapy; whereas macrophage depletion prevented this immunotherapy-induced cachexia. These studies strongly indicate that age-related changes in macrophages play a key role in driving cancer cachexia in the elderly, particularly during immunotherapy, and sabotage elderly anti-tumor immune responses.

Inflammatory markers and overall survival in older adults with cancer

BACKGROUND

Our aim was to evaluate the prognostic impact of three inflammatory markers - neutrophil lymphocyte ratio (NLR), platelet lymphocyte ratio (PLR) and lymphocyte monocyte ratio (LMR) - on overall survival (OS) in older adults with cancer.

MATERIALS AND METHODS

Our sample includes 144 patients age ≥ 65 years with solid tumor cancer who completed a cancer-specific Geriatric Assessment (GA) from 2010 to 2014 and had pretreatment CBC with differential. NLR was dichotomized a previously reported cut-off value of 3.5, while PLR and LMR were dichotomized at the median. Cox proportional hazards models evaluated whether NLR, PLR and LMR were predictive of OS independent of covariates including a recently developed 3-item GA-derived prognostic scale consisting of (1) "limitation in walking several blocks", (2) "limitation in shopping", and (3) "≥ 5% unintentional weight loss in 6 months".

RESULTS

Median age was 72 years, 53% had breast cancer, 27% had stage 4 cancer, 14% had Karnofsky Performance Status (KPS) < 80, 11% received less intensive than standard treatment for stage, and 39% had NLR > 3.5. In univariable analysis, higher NLR and PLR and lower LMR were significantly associated with worse OS. NLR remained a significant predictor of OS (HR = 2.16, 95% CI; 1.10-4.25, p = .025) after adjusting for cancer type, stage, age, KPS, treatment intensity, and the GA-derived prognostic scale.

CONCLUSION

NLR > 3.5 is predictive of poorer OS in older adults with cancer, independent of traditional prognostic factors and the GA-derived prognostic scale.

Aged neutrophils accumulate in lymphoid tissues from healthy elderly mice and infiltrate T- and B-cell zones

The average age of the human population is rising, leading to an increasing burden of age-related diseases, including increased susceptibility to infection. However, immune function can decrease with age which could impact on processes that require a functional immune system. Aging is also characterized by chronic low-grade inflammation which could further impact immune cell function. While changes to neutrophils in blood during aging have been described, little is known in aging lymphoid organs. This study used female C57BL/6J mice comparing bone marrow (BM), spleen and lymph nodes from young mice aged 2-3 months (equivalent to 18 human years) with healthy elderly mice aged 22-24 months (equivalent to 60-70 human years). Neutrophil proportions increased in BM and secondary lymphoid organs of elderly mice relative to their younger counterparts and presented an atypical phenotype. Interestingly, neutrophils from elderly spleen and lymph nodes were long lived (with decreased apoptosis via Annexin V staining and increased proportion of BrdU^neg mature cells) with splenic neutrophils also demonstrating a hypersegmented morphology. Furthermore, splenic neutrophils of elderly mice expressed a mixed phenotype with increased expression of activation markers, CD11b and ICAM-1, increased proinflammatory TNFα, yet increased anti-inflammatory transforming growth factor-beta. Elderly splenic architecture was compromised, as the marginal zone (required for clearing infections) was contracted. Moreover, neutrophils from elderly but not young mice accumulated in lymph node and splenic T- and B-cell zones. Overall, the expansion of functionally compromised neutrophils could contribute to increased susceptibility to infection observed in the elderly.

A Futile Battle? Protein Quality Control and the Stress of Aging

There exists a phenomenon in aging research whereby early life stress can have positive impacts on longevity. The mechanisms underlying these observations suggest a robust, long-lasting induction of cellular defense mechanisms. These include the various unfolded protein responses of the endoplasmic reticulum (ER), cytosol, and mitochondria. Indeed, ectopic induction of these pathways, in the absence of stress, is sufficient to increase lifespan in organisms as diverse as yeast, worms, and flies. Here, we provide an overview of the protein quality control mechanisms that operate in the cytosol, mitochondria, and ER and discuss how they affect cellular health and viability during stress and aging.

Aging and cancer: The role of macrophages and neutrophils

Impaired immune function has been implicated in the declining health and higher incidence of cancer in the elderly. However, age-related changes to immunity are not completely understood. Neutrophils and macrophages represent the first line of defence yet their ability to phagocytose pathogens decrease with aging. Cytotoxic T lymphocytes are critical in eliminating tumors, but T cell function is also compromised with aging. T cell responses can be regulated by macrophages and may depend on the functional phenotype macrophages adopt in response to microenvironmental signals. This can range from pro-inflammatory, anti-tumorigenic M1 to anti-inflammatory, pro-tumorigenic M2 macrophages. Macrophages in healthy elderly adipose and hepatic tissue exhibit a more pro-inflammatory M1 phenotype compared to young hosts whilst immunosuppressive M2 macrophages increase in elderly lymphoid tissues, lung and muscle. These M2-like macrophages demonstrate altered responses to stimuli. Recent studies suggest that neutrophils also regulate T cell function and, like macrophages, neutrophil function is modulated with aging. It is possible that age-modified tissue-specific macrophages and neutrophils contribute to chronic low-grade inflammation that is associated with dysregulated macrophage-mediated immunosuppression, which together are responsible for development of multiple pathologies, including cancer. This review discusses recent advances in macrophage and neutrophil biology in healthy aging and cancer.

Adaptive Memory of Human NK-like CD8+ T-Cells to Aging, and Viral and Tumor Antigens

Human natural killer (NK)-like CD8⁺ T-cells are singular T-cells that express both T and NK cell markers such as CD56; their frequencies depend on their differentiation and activation during their lifetime. There is evidence of the presence of these innate CD8⁺ T-cells in the human umbilical cord, highlighting the necessity of investigating whether the NK-like CD8⁺ T-cells arise in the early stages of life (gestation). Based on the presence of cell surface markers, these cells have also been referred to as CD8⁺KIR⁺ T-cells, innate CD8⁺ T-cells, CD8⁺CD28⁻KIR⁺ T-cells or NKT-like CD8⁺CD56⁺ cells. However, the functional and co-signaling significance of these NK cell receptors on NK-like CD8⁺ T-cells is less clear. Also, the diverse array of costimulatory and co-inhibitory receptors are spatially and temporally regulated and may have distinct overlapping functions on NK-like CD8⁺ T-cell priming, activation, differentiation, and memory responses associated with different cell phenotypes. Currently, there is no consensus regarding the functional properties and phenotypic characterization of human NK-like CD8⁺ T-cells. Environmental factors, such as aging, autoimmunity, inflammation, viral antigen re-exposure, or the presence of persistent tumor antigens have been shown to allow differentiation (“adaptation”) of the NK-like CD8⁺ T-cells; the elucidation of this differentiation process and a greater understanding of the characteristics of these cells could be important for their eventual in potential therapeutic applications aimed at improving protective immunity. This review will attempt to elucidate an understanding of the characteristics of these cells with the goal toward their eventual use in potential therapeutic applications aimed at improving protective immunity.

The anti-aging effects of LW-AFC via correcting immune dysfunctions in senescence accelerated mouse resistant 1 (SAMR1) strain

Although there were considerable advances in the anti-aging medical field, it is short of therapeutic drug for anti-aging. Mounting evidence indicates that the immunosenescence is the key physiopathological mechanism of aging. This study showed the treatment of LW-AFC, an herbal medicine, decreased the grading score of senescence, increased weight, prolonged average life span and ameliorated spatial memory impairment in 12- and 24-month-old senescence accelerated mouse resistant 1 (SAMR1) strain. And these anti-aging effects of LW-AFC were more excellent than melatonin. The administration of LW-AFC enhanced ConA- and LPS-induced splenocyte proliferation in aged SAMR1 mice. The treatment of LW-AFC not only reversed the decreased the proportions of helper T cells, suppressor T cells and B cells, the increased regulatory T cells in the peripheral blood of old SAMR1 mice, but also could modulate the abnormal secretion of IL-1β, IL-2, IL-6, IL-17, IL-23, GM-CSF, IFN-γ, TNF-α, TNF-β, RANTES, eotaxin, MCP-1, IL-4, IL-5, IL-10 and G-CSF. These data indicated that LW-AFC reversed the immunosenescence status by restoring immunodeficiency and decreasing chronic inflammation and suggested LW-AFC may be an effective anti-aging agent.

Sexual dimorphism in the aged rat CD4+ T lymphocyte-mediated immune response elicited by inoculation with spinal cord homogenate

Considering the crucial pathogenic role of CD4+ T cells in experimental autoimmune encephalomyelitis (EAE) and the opposite direction of the sexual dimorphism in the severity of the disease in 22-24-and 3-month-old dark agouti rats, sex differences in CD4+ T-cell-mediated immune response in aged rats immunized for EAE were examined and compared with those in young animals. In the inductive phase of EAE, fewer activated CD4+ lymphocytes were retrieved from draining lymph nodes of male (developing less severe disease) compared with female rats, due, at least partly, to their lesser expansion. The former reflected a greater suppressive capacity of CD4+CD25+Foxp3+ cells. Consequently, CD4+ lymphocyte infiltration into the spinal cord of aged male rats was diminished. At the peak of EAE, the frequency of reactivated cells was lower, whereas that of the regulatory CD4+ cells was higher in male rat spinal cord. Consistently, microglial activation and the expression of proinflammatory/damaging cytokines in male rat spinal cord mononuclear cells were diminished. Additionally, the frequency of the highly pathogenic IL-17+IFN-γ+ T lymphocytes infiltrating their spinal cord was lower. Together, these results point to (i) an age-specificity in CD4+ cell-mediated immune response and (ii) mechanisms underlying the sex differences in this response in aged rats.

The effect of aging on the frequency, phenotype and cytokine production of human blood CD4 + CXCR5 + T follicular helper cells: comparison of aged and young subjects

Background

T cell-dependent B-cell responses decline with age, indicating declined cognate helper activity of aged CD4 + T cells for B cells. However, the mechanisms remain unclear. T follicular helper (Tfh) cells, a novel T helper subset, play an essential role in helping B cells differentiation into long-lived plasma cells in germinal center (GC) or short-lived plasma cells. In the present study, we proposed that there might existe changes of proportion, phenotype or cytokine production of blood Tfh cells in healthy elderly individuals compared with healthy young individuals.

Results

The results showed that frequencies of aged blood CXCR5 + CD4 + Tfh cells increased compared with young subjects. Both aged and young blood CXCR5 + CD4 + Tfh cells constitutively expressed CD45RO, CCR7 and CD28, and few of these cells expressed CD69 or HLA-DR, which indicated that they were resting memory cells. There was no significant difference of IL-21 frequency production by aged blood CXCR5 + CD4 + Tfh determined by FACS compared with young individuals, however, aged PBMCs produced significantly higher levels of IL-21 evaluated by ELISA. Furthermore, there were no significant differences of percentages of IFN-γ, IL-4, IL-17 or IL-22 production by aged Tfh cells compared with their counterparts of young individuals respectively. However, frequencies of IL-17+ cells within aged CD4 + CXCR5-T cells were markedly lower than in the young individuals. Furthermore we observed different frequencies of IFN-γ, IL-17, IL-4 or IL-22 production by Tfh or by CD4 + CXCR5- cells in aged and young subjects respectively.

Conclusions

Our data demonstrated that the frequencies of blood memory CXCR5 + CD4 + Tfh cells increased in the elderly population. There were similar frequencies of Th characterized cytokine production such as IL-21, IFN-γ, IL-4, IL-17 or IL-22 in aged and young Tfh cells. However, aged PBMCs produced a significantly higher amount of IL-21 compare to young subjects.

Meta-analysis on blood transcriptomic studies identifies consistently coexpressed protein-protein interaction modules as robust markers of human aging

The bodily decline that occurs with advancing age strongly impacts on the prospects for future health and life expectancy. Despite the profound role of age in disease etiology, knowledge about the molecular mechanisms driving the process of aging in humans is limited. Here, we used an integrative network-based approach for combining multiple large-scale expression studies in blood (2539 individuals) with protein–protein Interaction (PPI) data for the detection of consistently coexpressed PPI modules that may reflect key processes that change throughout the course of normative aging. Module detection followed by a meta-analysis on chronological age identified fifteen consistently coexpressed PPI modules associated with chronological age, including a highly significant module (P = 3.5 × 10⁻³⁸) enriched for ‘T-cell activation’ marking age-associated shifts in lymphocyte blood cell counts (R² = 0.603; P = 1.9 × 10⁻¹⁰). Adjusting the analysis in the compendium for the ‘T-cell activation’ module showed five consistently coexpressed PPI modules that robustly associated with chronological age and included modules enriched for ‘Translational elongation’, ‘Cytolysis’ and ‘DNA metabolic process’. In an independent study of 3535 individuals, four of five modules consistently associated with chronological age, underpinning the robustness of the approach. We found three of five modules to be significantly enriched with aging-related genes, as defined by the GenAge database, and association with prospective survival at high ages for one of the modules including ASF1A. The hereby-detected age-associated and consistently coexpressed PPI modules therefore may provide a molecular basis for future research into mechanisms underlying human aging.

Immunosenescence and gender: a study in healthy Cubans

Background

The progressive decline in the immune function during ageing is termed immunosenescence. Previous studies have reported differences between males and females in the distribution and cell responses of lymphocyte subsets. Most studies of immunosenescence have been done in populations of industrialized countries living in a rather cold environment, and facing lower antigenic challenges such as Cytomegalovirus (CMV). The aim of this study was to determine the effect of ageing on lymphocytes in a population with a high prevalence of CMV infection in all ages, and to compare gender differences related to the immunosenescence markers.

Results

Different populations of peripheral blood leukocytes from healthy young and old IgG-CMV seropositive individuals were examined using flow cytometry. With age, the number and frequency of B cells and T cells significantly decreased, while highly differentiated T cells increased. Such changes were different in males and females. The age-associated decline of less differentiated lymphocyte subsets (CD19, CD4 and CD8 cells) and the increase of highly differentiated T cells were more prominent in females. In males, there were no significant changes in CD19, CD4 and CD8 subsets but there was a significant increase in the proportion of highly differentiated T cells.

Conclusion

Shifts in lymphocyte subsets distribution were influenced by age and gender in an IgG-CMV seropositive population. These results suggest different patterns of immunosenescence in respect to gender differences. These patterns could have implications in the design of immunotherapy in the elderly.

Analysis of the rs20541 (R130Q) polymorphism in the IL-13 gene in patients with elderly-associated chronic inflammatory diseases

OBJECTIVE

To investigate whether there is association between the rs20541 (R130Q) polymorphism in the IL-13 gene with disease susceptibility and clinical subsets in patients with elderly-associated inflammatory chronic diseases.

MATERIAL AND METHODS

78 patients with giant cell arteritis (GCA), 174 with polymyalgia rheumatica (PMR), 90 elderly-onset rheumatoid arthritis (EORA), and 465 healthy controls from the same geographic area were studied. The rs20541 (R130Q) polymorphism in the IL-13 gene was evaluated by PCR-RFLP. Circulating levels of IL-13 were measured by ELISA.

RESULTS

A higher frequency of the AA genotype [2.349 (0.994-5.554)], as well as the allele A [1.589 (1.085-2.328] and the A carriers [1.656 (1.021-2.686)] (p<0.05) was observed in the GCA patients. No significant differences were observed in the PMR and EORA patients as compared with the healthy controls. Neither difference was observed among the different disease groups studied. In GCA patients, differences in the genotype were associated with a worse prognosis. In PMR patients, the AA genotype was associated with higher levels of serum IL-13 than the GA one. However, such an association was not detected for controls and the other disease groups.

CONCLUSIONS

GCA is more frequent in carriers of the rs20541 (R130Q) polymorphism in the IL-13 gene. The utility of this polymorphism to predict the GCA prognosis must be confirmed in studies with a higher number of patients.

In vivo electroporation restores the low effectiveness of DNA vaccination against HER-2/neu in aging

Experimental evidence has been provided that cancer vaccines are less effective at older age than in young adults. In this study, we evaluated the possibility to recover the low effectiveness of DNA immunization against HER-2/neu increasing plasmid uptake by cells from old mice through electroporation with the aim to enhance the activation of specific immune responses. Young and old Balb/c mice received two immunizations with a pCMV-ECDTM DNA plasmid using plasmid intramuscular injection followed by electroporation (IM + E) or plasmid intramuscular injection alone (IM), and successively, they were challenged with syngeneic HER-2/neu overexpressing TUBO cells. Young mice were completely protected whereas less than 60% protection was observed in old mice after IM immunization. IM + E immunization completely protected old mice against a TUBO cell challenge. The protection was associated with increased transgene expression in the site of immunization and with the induction of both humoral and cell-mediated immunity in old mice. We conclude that the effectiveness of anticancer DNA vaccination in old ages may be improved increasing plasmid uptake and transgene expression through electroporation, suggesting the relevant role of the first steps of the immunization process in the success of cancer vaccines at older age.

Age-related changes in natural killer cell receptors from childhood through old age

Most studies on natural killer (NK) cells and aging have focused on overall cell numbers and global cytotoxic activity. NK cell functions are controlled by surface receptors belonging to three major families: killer cell immunoglobulin-like receptors (KIRs), natural cytotoxicity receptors (NCRs), and C-type lectins. The expression of these receptors was investigated from childhood through old age in T, NKT- and NK cells and also in the CD56(dim) (cytotoxic) and CD56(bright) (responsible for cytokine production) NK cell subsets. A decrease in the expression of activating receptors (NKp30 and NKp46) was observed in NK cells in elderly individuals. KIR expression was increased only in the CD56(bright) subset. Children presented similar results regarding expression of NKp30 and KIR, but not NKp46. NKG2D expression was decreased in T cells of elderly subjects. Analysis of KIR genotype revealed that KIR2DL5 and KIR2DS3 were significantly associated with old age. Cytotoxic activity was preserved from childhood through old age, suggesting that the increase of the absolute number of CD56(dim), observed in elderly, may represent a compensatory mechanism for the receptor expression alterations. This initial study provides the framework for more focused studies of this subject, which are necessary to determine whether the changing balance of NK receptor expression may influence susceptibility to infectious, inflammatory, and neoplastic diseases.

A novel adjuvant for vaccine development in the aged

A conformationally-biased, response-selective agonist of human C5a(65-74) (EP67) activated antigen presenting cells (APC) from aged C57Bl/6 mice in vitro and the generation of antigen (Ag)-specific antibody (Ab) responses in aged mice in vivo. EP67, induced the release of the pro-inflammatory cytokines IL-6, TNFα, and INFγ from splenic APCs obtained from both aged and young mice. Both aged and young mice produced high Ag-specific IgG Ab titers when immunized with EP67-containing vaccines to ovalbumin (OVA-EP67) and to a protein (rPrp1) from the cell wall of Coccidioides (rPrp1-EP67). Immunization with EP67-containing vaccines resulted in higher IgG titers in both young and aged mice compared to mice immunized with OVA adsorbed to alum (OVA/alum) and Prp1 admixed with CpG (rPrp1 +CpG). Aged and young mice immunized with the EP67-containing vaccines generated higher titers of IgG1 and IgG2b relative to their aged-matched counterparts immunized with OVA/alum or Prp1 +CpG. These results indicate that EP67 induces humoral immunity in aged mice not obtainable with alum and CpG. These results support the use of EP67 as a potential vaccine adjuvant suited to the elderly.

The effect of ageing on human lymphocyte subsets: comparison of males and females

Background

There is reported to be a decline in immune function and an alteration in the frequency of circulating lymphocytes with advancing age. There are also differences in ageing and lifespan between males and females. We performed this study to see if there were differences between males and females in the frequency of the different lymphocyte subsets with age.

Results

Using flow cytometry we have examined different populations of peripheral blood leukocytes purified from healthy subjects with age ranging from the third to the tenth decade. We used linear regression analysis to determine if there is a linear relationship between age and cell frequencies. For the whole group, we find that with age there is a significant decline in the percentage of naïve T cells and CD8⁺ T cells, and an increase in the percentage of effector memory cells, CD4⁺foxp3⁺ T cells and NK cells. For all cells where there was an effect of ageing, the slope of the curve was greater for men than for women and this was statistically significant for CD8⁺αβ⁺ T cells and CD3⁺CD45RA^-CCR7^- effector memory cells. There was also a difference for naïve cells but this was not significant.

Conclusion

The cause of the change in percentage of lymphocyte subsets with age, and the different effects on males and females is not fully understood but warrants further study.

Protein phosphatase 2A (PP2A) is increased in old murine B cells and mediates p38 MAPK/tristetraprolin dephosphorylation and E47 mRNA instability

The transcription factor E47, which regulates immunoglobulin class switch in murine splenic B cells, is down-regulated in aged B cells due to reduced mRNA stability. Part of the decreased stability of E47 mRNA is mediated by tristetraprolin (TTP), a physiological regulator of mRNA stability. We have previously shown that TTP mRNA and protein expression are higher in old B cells, and the protein is less phosphorylated in old B cells, both of which lead to more binding of TTP to the 3'-UTR of E47 mRNA, thereby decreasing its stability. PP2A is a protein phosphatase that plays an important role in the regulation of a number of major signaling pathways. Herein we show that not only the amount but also the activity of PP2A is increased in old B cells. As a consequence of this higher phosphatase activity in old B cells, p38 MAPK and TTP (either directly or indirectly by PP2A) are less phosphorylated as compared with young B cells. PP2A dephosphorylation of p38 MAPK and/or TTP likely generates more binding of the hypophosphorylated TTP to the E47 mRNA, inducing its degradation. This mechanism may be at least in part responsible for the age-related decrease in class switch.

Immunosenescence and cancer vaccines

Experimental and clinical data demonstrate that ageing is associated with the gradual deterioration of the immune system, generally referred to as immunosenescence. Age-related immune dysfunction may have an impact not only on the incidence of cancer, but also on the preventive and therapeutic approaches, which are based on immune system activation. Over the last few years the use of immunological measures to prevent cancer in experimental mouse models involving preimmunization with new vaccines against even a poor or apparently non-immunogenic tumour has yielded worse outcomes in older age than in young adults. Different mechanisms, which may be due to age-related numerical or functional dysfunction of immune cells and/or to tumour microenvironmental changes, could be responsible for this defect. This review summarises the impact of immunosenescence on the effectiveness of cancer vaccines, knowledge of cancer immunisation in old age and the potential mechanisms implicated in the poorer effectiveness of anticancer immune-based approaches in advanced age. Several approaches to, and possibilities of correcting the low effectiveness of immunisation procedures in old age are described.

Effect of ageing on CMV-specific CD8 T cells from CMV seropositive healthy donors

BACKGROUND

Ageing is associated with changes in the immune system with substantial alterations in T-lymphocyte subsets. Cytomegalovirus (CMV) is one of the factors that affect functionality of T cells and the differentiation and large expansions of CMV pp65-specific T cells have been associated with impaired responses to other immune challenges. Moreover, the presence of clonal expansions of CMV-specific T cells may shrink the available repertoire for other antigens and contribute to the increased incidence of infectious diseases in the elderly. In this study, we analyse the effect of ageing on the phenotype and frequency of CMV pp65-specific CD8 T cell subsets according to the expression of CCR7, CD45RA, CD27, CD28, CD244 and CD85j.

RESULTS

Peripheral blood from HLA-A2 healthy young, middle-aged and elderly donors was analysed by multiparametric flow cytometry using the HLA-A*0201/CMV pp65(495-504) (NLVPMVATV) pentamer and mAbs specific for the molecules analysed. The frequency of CMV pp65-specific CD8 T cells was increased in the elderly compared with young and middle-aged donors. The proportion of naïve cells was reduced in the elderly, whereas an age-associated increase of the CCR7(null) effector-memory subset, in particular those with a CD45RA(dim) phenotype, was observed, both in the pentamer-positive and pentamer-negative CD8 T cells. The results also showed that most CMV pp65-specific CD8 T cells in elderly individuals were CD27/CD28 negative and expressed CD85j and CD244.

CONCLUSION

The finding that the phenotype of CMV pp65-specific CD8 T cells in elderly individuals is similar to the predominant phenotype of CD8 T cells as a whole, suggests that CMV persistent infections contributes to the age-related changes observed in the CD8 T cell compartment, and that chronic stimulation by other persistent antigens also play a role in T cell immunosenescence. Differences in subset distribution in elderly individuals showing a decrease in naive and an increase in effector-memory CD8 T cells may be relevant in the age-associated defective immune response.

Reference ranges and age-related changes of peripheral blood lymphocyte subsets in Chinese healthy adults

This study was performed to build region-specific reference ranges of peripheral blood lymphocyte subsets for Chinese healthy adults from the young to the elderly and analyze the trends of changes in lymphocyte subsets for evaluating the impact of age on the values. 151 healthy adults aged 19-86 were recruited based on the SENIEUR protocol. Three sets of reference ranges were finally built applicable for the healthy young (19-44 years), middle-aged (45-64 years) and elder adults ([Symbol: see text]65). Comparisons in parameters among the three cohorts showed that a statistically significant increase in CD16CD56+ NK cell was observed between the middle-aged and elder cohorts, whereas for the majority of the parameters, a significant decline was observed between the young and the middle-aged cohorts. Further results showed that inverse correlations were observed between the age and CD19(+) B, CD3(+) T, CD3(+)CD4(+) T, CD4(+)CD45RA(+)CD62L(+) naïve T cell and CD4(+)CD28(+)/CD4(+), while the positive one was identified between the age and the NK cell. These significant changes of the most of immune parameters provided evidence for immunosenescence. Notably, T cell activation markers of CD8(+)CD38(+) and CD8(+)HLA-DR(+) showed reverse trends of association with age, which provides a clue for further researches on the mechanisms underlying the paradoxical clinical presentation of the elder patients.

Mechanisms of murine dendritic cell antitumor dysfunction in aging

Effective cancer immunotherapy depends on the body's ability to generate tumor antigen-presenting cells and tumor-reactive effector lymphocytes. As the most potent antigen presenting cells (APCs), dendritic cells (DCs) are capable of sensitizing T cells to new and recall antigens. Clinical trials of antigen-pulsed autologous DCs have been conducted in patients with a number of hematological and solid cancers, including malignant melanoma, lymphoma, myeloma, and non-small cell lung cancer. These studies suggest that antigen-loaded DC vaccination is a potentially safe and effective cancer therapy. However, the clinical results have been variable. Since the elderly are preferentially affected by diseases targeted by DC-directed immunotherapy, it is quite striking that few studies to date have focused on the effect of aging on DC function, a key aspect of optimal immunotherapy design in an aging population. In the present paper, we will discuss the consequences of aging on murine bone marrow-derived DC function and their use in cancer immunotherapy.

Mechanisms for decreased function of B cells in aged mice and humans

The immune system has been known for some time to be compromised in aged individuals, e.g., both mice and humans, and in both humoral and cellular responses. Our studies have begun to elucidate intrinsic B lymphocyte defects in Ig class switch recombination, activation-induced cytidine deaminase, and E47 transcription factor expression. These defects occur in both mice and humans. Our studies have also shown that tristetraprolin is one of the key players in regulating the decreased E47 mRNA stability in aged B lymphocytes. These and current studies should lead to improvements in B lymphocyte function in aged populations.