Aging-associated subpopulations of human CD8+ T-lymphocytes identified by their CD28 and CD57 phenotypes

Immune cell phenotype and function patterns across the life course in individuals from rural Uganda

Background

To determine the pattern of immune cell subsets across the life span in rural sub-Saharan Africa (SSA), and to set a reference standard for cell subsets amongst Africans, we characterised the major immune cell subsets in peripheral blood including T cells, B cells, monocytes, NK cells, neutrophils and eosinophils, in individuals aged 3 to 89 years from Uganda.

Methods

Immune phenotypes were measured using both conventional flow cytometry in 72 individuals, and full spectrum flow cytometry in 80 individuals. Epstein-Barr virus (EBV) IFN-γ T cell responses were quantified in 332 individuals using an ELISpot assay. Full blood counts of all study participants were also obtained.

Results

The percentages of central memory (TCM) and senescent CD4+ and CD8+ T cell subsets, effector memory (TEM) CD8+ T cells and neutrophils increased with increasing age. On the other hand, the percentages of naïve T (TN) and B (BN) cells, atypical B cells (BA), total lymphocytes, eosinophils and basophils decreased with increasing age. There was no change in CD4+ or CD8+ T effector memory RA (TEMRA) cells, exhausted T cells, NK cells and monocytes with age. Higher eosinophil and basophil percentages were observed in males compared to females. T cell function as measured by IFN-γ responses to EBV increased with increasing age, peaking at 31-55 years.

Conclusion

The percentages of cell subsets differ between individuals from SSA compared to those elsewhere, perhaps reflecting a different antigenic milieu. These results serve as a reference for normal values in this population.

NAD+ supplementation prevents STING-induced senescence in CD8+ T cells by improving mitochondrial homeostasis

Understanding the connection between senescence phenotypes and mitochondrial dysfunction is crucial in aging and premature aging diseases. Loss of mitochondrial function leads to a decline in T cell function, which plays a significant role in this process. However, more research is required to determine if improving mitochondrial homeostasis alleviates senescence phenotypes. Our research has shown an association between NAD+ and senescent T cells through the cGAS-STING pathway, which can lead to an inflammatory phenotype. Further research is needed to fully understand the role of NAD+ in T-cell aging and how it can be utilized to improve mitochondrial homeostasis and alleviate senescence phenotypes. We demonstrate here that mitochondrial dysfunction and cellular senescence with a senescence-associated secretory phenotype (SASP) occur in senescent T cells and tumor-bearing mice. Senescence is mediated by a stimulator of interferon genes (STING) and involves ectopic cytoplasmic DNA. We further show that boosting intracellular NAD+ levels with nicotinamide mononucleotide (NMN) prevents senescence and SASP by promoting mitophagy. NMN treatment also suppresses senescence and neuroinflammation and improves the survival cycle of mice. Encouraging mitophagy may be a useful strategy to prevent CD8+ T cells from senescence due to mitochondrial dysfunction. Additionally, supplementing with NMN to increase NAD+ levels could enhance survival rates in mice while also reducing senescence and inflammation, and enhancing mitophagy as a potential therapeutic intervention.

Effects of Korean red ginseng on T-cell repopulation after autologous hematopoietic stem cell transplantation in childhood cancer patients

Background

Although the survival outcomes of childhood cancer patients have improved, childhood cancer survivors suffer from various degrees of immune dysfunction or delayed immune reconstitution. This study aimed to investigate the effect of Korean Red Ginseng (KRG) on T cell recovery in childhood cancer patients who underwent autologous hematopoietic stem cell transplantation (ASCT) from the perspective of inflammatory and senescent phenotypes.

Methods

This was a single-arm exploratory trial. The KRG group (n = 15) received KRG powder from month 1 to month 12 post-ASCT. We compared the results of the KRG group with those of the control group (n = 23). The proportions of T cell populations, senescent phenotypes, and cytokine production profiles were analyzed at 1, 3, 6, and 12 months post-ASCT using peripheral blood samples.

Results

All patients in the KRG group completed the treatment without any safety issues and showed a comparable T cell repopulation pattern to that in the control group. In particular, KRG administration influenced the repopulation of CD4+ T cells via T cell expansion and differentiation into effector memory cell re-expressing CD45RA (EMRA) cells. Although the KRG group showed an increase in the number of CD4+ EMRA cells, the expression of senescent and exhausted markers in these cells decreased, and the capacity for senescence-related cytokine production in the senescent CD28- subset was ameliorated.

Conclusions

These findings suggest that KRG promotes the repopulation of CD4+ EMRA T cells and regulates phenotypical and functional senescent changes after ASCT in pediatric patients with cancer.

Low levels of peripheral blood activated and senescent T cells characterize people with HIV-1-associated neurocognitive disorders

Background

HIV infection induces a 75% increase in the risk of developing neurocognitive impairment (NCI), which has been linked to immune activation. We therefore looked for immune activation markers correlating with NCI.

Method

Sixty-five people aged 55-70 years living with controlled HIV-1 infection were enrolled in the study and their neurocognitive ability was assessed according to the Frascati criteria. Fifty-nine markers of T4 cell, T8 cell, NK cell, and monocyte activation, inflammation and endothelial activation were measured in their peripheral blood. White matter hyperintensities (WMH) were identified by magnetic resonance imaging. Double hierarchical clustering was performed for the activation markers and 240 patients including the 65 whose neurocognitive performance had been evaluated.

Results

Thirty-eight percent of volunteers presented NCI. Twenty-four percent of them were asymptomatic and fourteen percent had a mild disorder. Strikingly, activated (HLA-DR+) as well as senescent (CD57+CD28-CD27±) T4 cells and T8 cells were less prevalent in the peripheral blood of participants with NCI than in participants without the disorder. Accordingly, the percentage of HLA-DR+ T4 cells was lower in volunteers with periventricular and deep WMH. The double hierarchical clustering unveiled six different immune activation profiles. The neurocognitive performances of participants with two of these six profiles were poor. Here again, these two profiles were characterized by a low level of T4 and T8 cell activation and senescence.

Conclusion

Our observation of low circulating levels of activated and senescent T cells in HIV-1 patients with NCI raises the interesting hypothesis that these lymphocytes may be recruited into the central nervous system.

T-cell phenotype including CD57+ T follicular helper cells in the tumor microenvironment correlate with a poor outcome in follicular lymphoma

T-lymphocytes are prevalent in the tumor microenvironment of follicular lymphoma (FL). However, the phenotype of T-cells may vary, and the prevalence of certain T-cell subsets may influence tumor biology and patient survival. We therefore analyzed a cohort of 82 FL patients using CyTOF to determine whether specific T-cell phenotypes were associated with distinct tumor microenvironments and patient outcome. We identified four immune subgroups with differing T-cell phenotypes and the prevalence of certain T-cell subsets was associated with patient survival. Patients with increased T cells with early differentiation stage tended to have a significantly better survival than patients with increased T-cells of late differentiation stage. Specifically, CD57+ TFH cells, with a late-stage differentiation phenotype, were significantly more abundant in FL patients who had early disease progression and therefore correlated with an inferior survival. Single cell analysis (CITE-seq) revealed that CD57+ TFH cells exhibited a substantially different transcriptome from CD57- TFH cells with upregulation of inflammatory pathways, evidence of immune exhaustion and susceptibility to apoptosis. Taken together, our results show that different tumor microenvironments among FL patients are associated with variable T-cell phenotypes and an increased prevalence of CD57+ TFH cells is associated with poor patient survival.

Heat shock proteins and cellular senescence in humans: A systematic review

Cellular senescence (CS) is a permanent arrest of cell growth and exit of the cell cycle. It is an important tumor suppression mechanism and has a key role in wound healing, tissue regeneration, and prevention of tissue fibrosis. Despite the short-term benefits of CS, accumulation of senescent cells has deleterious effects and is associated with several pathological age-related phenotypes. As Heat Shock Proteins (HSP) are associated with cyto-protection, their role in longevity and CS became a research interest. However, an overview of the relationship between HSP and CS in humans still lacks in the literature. To provide an overview of the current state of the literature, this systematic review focused on the role of HSP in the development of CS in humans. PubMed, Web of Science and Embase were systematically screened for studies on the relationship between HSP and CS in humans. A total of 14 articles were eligible for inclusion. The heterogeneity and lack of numerical reporting of outcomes obstructed the conduction of a meta-analysis. The results consistently show that HSP depletion results in increased CS, while overexpression of HSP decreases CS, whether in cancer, fibroblasts, or stem cell lines. This systematic review summarized the literature on the prospective role of HSP in the development of CS in humans.

Immune senescence in non-small cell lung cancer management: therapeutic relevance, biomarkers, and mitigating approaches

INTRODUCTION

Lung cancer and mainly non-small cell lung cancer (NSCLC) still remain a prevalent malignancy worldwide despite sustained screening approaches. Furthermore, a significant proportion of the cases are diagnosed at advanced stages when conservative therapy is often unsuccessful. Cell senescence is an endogenous antitumor weapon but when it is upregulated exerts opposite activities favoring tumor metastasizing and poor response to therapy. However, little is known about this dangerous relationship between cell senescence and NSCLC outcome or on potential approaches to mitigate its unfavorable consequences.

AREAS COVERED

We discuss cell senescence focusing on immune senescence, its cell and humoral effectors (namely immune senescence associated secretory phenotype-iSASP), its impact on NSCLC outcome, and its biomarkers. Senotherapeutics as mitigating approaches are also considered based on the availability of experimental data pertinent to NSCLC.

EXPERT OPINION

Characterization of NSCLC subsets in which immune senescence is a risk factor for poor prognosis and poor therapeutic response might be very helpful in supporting the addition of senotherapeutics to conventional cancer therapy. This approach has the potential to improve disease outcome but more studies in this area are necessary.

Assessment of cell cycle regulators in human peripheral blood cells as markers of cellular senescence

Cellular senescence has gained increasing interest during recent years, particularly due to causal involvement in the aging process corroborated by multiple experimental findings. Indeed, cellular senescence considered to be one of the hallmarks of aging, is defined as a stable growth arrest predominantly mediated by cell cycle regulators p53, p21 and p16. Senescent cells have frequently been studied in the peripheral blood of humans due to its accessibility. This review summarizes ex vivo studies describing cell cycle regulators as markers of senescence in human peripheral blood cells, along with detection methodologies and associative studies examining demographic and clinical characteristics. The utility of techniques such as the quantitative reverse transcriptase polymerase chain reaction (qRT-PCR), microarray, RNA sequencing and nCounter technologies for detection at the transcriptional level, along with Western blotting, enzyme-linked immunosorbent assay and flow cytometry at the translational level, will be brought up at salient points throughout this review. Notably, housekeeping genes or proteins serving as controls such as GAPDH and β-Actin, were found not to be stably expressed in some contexts. As such, optimization and validation of such genes during experimental design were recommended. In addition, the expression of cell cycle regulators was found to vary not only between different types of blood cells such as T cells and B cells but also between stages of cellular differentiation such as naïve T cells and highly differentiated T cells. On the other hand, the associations of the presence of cell cycle regulators with demographics (age, gender, ethnicity, and socioeconomic status), clinical characteristics (body mass index, specific diseases, disease-related parameters) and lifestyle vary in groups of participants. One envisions that increased understanding and insights into the assessment of cell cycle regulators as markers of senescence in human peripheral blood cells will help inform prognostication and clinical intervention in elderly individuals.

Emerging cellular senescence-centric understanding of immunological aging and its potential modulation through dietary bioactive components

Immunological aging is strongly associated with the observable deleterious effects of human aging. Our understanding of the causes, effects, and therapeutics of aging immune cells has long been considered within the sole purview of immunosenescence. However, it is being progressively realized that immunosenescence may not be the only determinant of immunological aging. The cellular senescence-centric theory of aging proposes a more fundamental and specific role of immune cells in regulating senescent cell (SC) burden in aging tissues that has augmented the notion of senescence immunotherapy. Now, in addition, several emerging studies are suggesting that cellular senescence itself may be prevalent in aging immune cells, and that senescent immune cells exhibiting characteristic markers of cellular senescence, similar to non-leucocyte cells, could be among the key drivers of various facets of physiological aging. The present review integrates the current knowledge related to immunosenescence and cellular senescence in immune cells per se, and aims at providing a cohesive overview of these two phenomena and their significance in immunity and aging. We present evidence and rationalize that understanding the extent and impact of cellular senescence in immune cells vis-à-vis immunosenescence is necessary for truly comprehending the notion of an 'aged immune cell'. In addition, we also discuss the emerging significance of dietary factors such as phytochemicals, probiotic bacteria, fatty acids, and micronutrients as possible modulators of immunosenescence and cellular senescence. Evidence and opportunities related to nutritional bioactive components and immunological aging have been deliberated to augment potential nutrition-oriented immunotherapy during aging.

Immunosenescence Study of T Cells: A Systematic Review

Background

Aging is accompanied by alterations in immune response which leads to increased susceptibility to infectious diseases, cancer, autoimmunity, and inflammatory disorders. This decline in immune function is termed as immunosenescence; however, the mechanisms are not fully elucidated. Experimental approaches of adaptive immunity, particularly for T cells, have been the main focus of immunosenescence research. This systematic review evaluates and discusses T cell markers implicated in immunosenescence.

Objective

To determine the best flow cytometry markers of circulating T cells associated with immunosenescence.

Methods

We systematically queried PubMed, MEDLINE, EBSCO, and BVS databases for original articles focused on two age groups of healthy humans: 18–44 (young adults) and >60 (older adults) years. In accordance with the Cochrane methodology, we synthesized data through qualitative descriptions and quantitative random effects meta-analysis due to extensive heterogeneity.

Results

A total of 36 studies conducted in the last 20 years were included for the qualitative analysis and four out of these studies were used to perform the meta-analysis. A significant decrease in naïve T cell subset was observed in older adults compared to young adults. Primary markers used to identify senescent cells were loss of CD28 and increased expression of CD57 and KLRG1 in terminally-differentiated memory T cell subset in older adults. Moreover, we observed an increase in proinflammatory cytokines and decrease in telomere length in old adult T cells. It was not possible to perform quantitative synthesis on cell markers, cytokines, and telomere length because of the significant variations between the groups, which is attributed to differences in protocols and unreported measurements, thus generating a high risk of bias.

Conclusions

Heterogeneity among studies in terms of data report, measurement techniques and high risk of bias were major impediments for performing a robust statistical analysis that could aid the identification of eligible flow cytometry markers of immunosenescence phenotype in T cells.

Immunosenescent characteristics of T cells in young patients following haploidentical haematopoietic stem cell transplantation from parental donors

Objectives

Paediatric and adolescent patients in need of allogeneic haematopoietic stem cell transplantation (HSCT) generally receive stem cells from older, unrelated or parental donors when a sibling donor is not available. Despite encouraging clinical outcomes, it has been suggested that immune reconstitution accompanied by increased replicative stress and a large difference between donor and recipient age may worsen immunosenescence in paediatric recipients.

Methods

In this study, paired samples were collected at the same time from donors and recipients of haploidentical haematopoietic stem cell transplantation (HaploSCT). We then conducted flow cytometry‐based phenotypic and functional analyses and telomere length (TL) measurements of 21 paired T‐cell sets from parental donors and children who received T‐cell‐replete HaploSCT with post‐transplant cyclophosphamide (PTCy).

Results

Senescent T cells, CD28⁻ or CD57⁺ cells, were significantly expanded in patients. Further, not only CD4⁺CD28⁻ T cells, but also CD4⁺CD28⁺ T cells showed reduced cytokine production capacity and impaired polyfunctionality compared with parental donors, whereas their TCR‐mediated proliferation capacity was comparable. Of note, the TL in patient T cells was preserved, or even slightly longer, in senescent T cells compared with donor cells. Regression analysis showed that senescent features of CD4⁺ and CD8⁺ T cells in patients were influenced by donor age and the frequency of CD28⁻ cells, respectively.

Conclusion

Our data suggest that in paediatric HaploSCT, premature immunosenescent changes occur in T cells from parental donors, and therefore, long‐term immune monitoring should be conducted.

CD28 and CD57 define four populations with distinct phenotypic properties within human CD8+ T cells

After repeated antigen exposure, both memory and terminally differentiated cells can be generated within CD8⁺ T cells. Although, during their differentiation, activated CD8⁺ T cells may first lose CD28, and CD28^- cells may eventually express CD57 as a subsequent step, a population of CD28⁺ CD57⁺ (DP) CD8⁺ T cells can be identified in the peripheral blood. How this population is distinct from CD28^- CD57^- (DN) CD8⁺ T cells, and from the better characterized non-activated/early-activated CD28⁺ CD57^- and senescent-like CD28^- CD57⁺ CD8⁺ T cell subsets is currently unknown. Here, RNA expression of the four CD8⁺ T cell subsets isolated from human PBMCs was analyzed using microarrays. DN cells were more similar to "early" highly differentiated cells, with decreased TNF and IFN-γ production, impaired DNA damage response and apoptosis. Conversely, increased apoptosis and expression of cytokines, co-inhibitory, and chemokine receptors were found in DP cells. Higher levels of DP CD8⁺ T cells were observed 7 days after Hepatitis B vaccination, and decreased levels of DP cells were found in rheumatoid arthritis patients. More DP and DN CD8⁺ T cells were present in the bone marrow, in comparison with PBMCs. In summary, our results indicate that DP and DN cells are distinct CD8⁺ T cell subsets displaying defined properties.

T cells and immune functions of plasma extracellular vesicles are differentially modulated from adults to centenarians

Aging is a universal and complex process that affects all tissues and cells types, including immune cells, in a process known as immunosenescence. However, many aspects of immunosenescence are not completely understood, as the characteristics of the immune cells of nonagenarians and centenarians or the features and implications of extracellular vesicles (EVs). In this study, we analyzed blood samples from 51 individuals aged 20-49 and 70-104 years. We found that senescent CD8 cells accumulate with age, while there is a partial reduction of senescent CD4 cells in nonagenarians and centenarians. Moreover, plasma EVs carry T cell specific markers, but no accumulation of "senescent-like EVs" was found within any of analyzed age groups. Our functional studies of cocultures of peripheral blood mononuclear cells and EVs showed that EVs enhance T cell viability and, under phytohemagglutinin stimulation, they influence cytokine secretion and cell activation in an age-dependent manner. These results underline the importance of EVs on the immune system functioning, and open new perspectives to further study their implication in human aging.

Macrophages in the Aging Liver and Age-Related Liver Disease

The number of individuals aged 65 or older is projected to increase globally from 524 million in 2010 to nearly 1. 5 billion in 2050. Aged individuals are particularly at risk for developing chronic illness, while being less able to regenerate healthy tissue and tolerate whole organ transplantation procedures. In the liver, these age-related diseases include non-alcoholic fatty liver disease, alcoholic liver disease, hepatitis, fibrosis, and cirrhosis. Hepatic macrophages, a population comprised of both Kupffer cells and infiltrating monocyte derived macrophages, are implicated in several chronic liver diseases and also play important roles in the homeostatic functions of the liver. The effects of aging on hepatic macrophage population dynamics, polarization, and function are not well understood. Studies performed on macrophages derived from other aged sources, such as the bone marrow, peritoneal cavity, lungs, and brain, demonstrate general reductions in autophagy and phagocytosis, dysfunction in cytokine signaling, and altered morphology and distribution, likely mediated by epigenetic changes and mitochondrial defects, that may be applicable to hepatic macrophages. This review highlights recent findings in macrophage developmental biology and function, particularly in the liver, and discusses the role of macrophages in various age-related liver diseases. A better understanding of the biology of aging that influences hepatic macrophages and thus the progression of chronic liver disease will be crucial in order to develop new interventions and treatments for liver disease in aging populations.

Effects of Physical Exercise on Markers of Cellular Immunosenescence: A Systematic Review

Aging affects negatively the immune system, defined as immunosenescence, which increases the susceptibility of elderly persons to infection, autoimmune disease, and cancer. There are strong indications that physical exercise in elderly persons may prevent the age-related decline in immune response without significant side effects. Consequently, exercise is being considered as a safe mode of intervention to reduce immunosenescence. The aim of this review was to appraise the existing evidence regarding the impact of exercise on surface markers of cellular immunosenescence in either young and old humans or animals. PubMed and Web of Science were systematically screened, and 28 relevant articles in humans or animals were retrieved. Most of the intervention studies demonstrated that an acute bout of exercise induced increases in senescent, naïve, memory CD4⁺ and CD8⁺ T-lymphocytes and significantly elevated apoptotic lymphocytes in peripheral blood. As regards long-term effects, exercise induced increased levels of T-lymphocytes expressing CD28⁺ in both young and elderly subjects. Few studies found an increase in natural killer cell activity following a period of training. We can conclude that exercise has considerable effects on markers of cellular aspects of the immune system. However, very few studies have been conducted so far to investigate the effects of exercise on markers of cellular immunosenescence in elderly persons. Implications for immunosenescence need further investigation.

Spleen atrophy related immune system changes attributed to infection of Angiostrongylus cantonensis in mouse model

The spleen is one of the most important peripheral immune organs, which is frequently affected in infectious diseases. Infectious diseases can induce splenic alterations including splenic atrophy and functional alteration, while splenic atrophy may in turn interferes with recovery of infectious diseases. Angiostrongyliasis is an infectious disease by Angiostrongylus cantonensis (A. cantonensis), which invade non-permissive hosts, such as humans and mice, to cause severe damage to the central nervous system (CNS) and acute inflammatory response. A. cantonensis infection-induced CNS injury has been confirmed to be due to profound immunopathology derived from peripheral immune components. However, the mechanism of immunopathology remains largely unknown. Here, we found that A. cantonensis invaded non-permissive hosts such as mice in the brain, but not in the other peripheral organs. However, this infection induced severe spleen atrophy. We further recognized that this atrophy is associated with a decrease of total splenocyte number and disruption of splenic structure due to reduced proliferation and increased apoptotosis. These also resulted in deterioration of T cell profile in the periphery with a low CD4/CD8 ratio and B/T cell ratio, and increased ratio of CD4⁺CD25⁺Foxp3⁺ Treg, CD8⁺CD28^- T, and CD38⁺T lymphocyte of spleen. Albendazole treatment can alleviate spleen atrophy and set T cell immune reconstitution in some extend. Our data showed that A. cantonensis infection can cause splenic atrophy. These results are suggested to put more emphasis to improve the function of immune system. Meanwhile, infection and treatment model will be useful to evaluate new therapeutic approaches which can prevent or reverse immunosuppression and infectious complications.

Menin Plays a Critical Role in the Regulation of the Antigen-Specific CD8+ T Cell Response upon Listeria Infection

Menin, a tumor suppressor protein, is encoded by the MEN1 gene in humans. Certain germinal mutations of MEN1 induce an autosomal-dominant syndrome that is characterized by concurrent parathyroid adenomas and several other tumor types. Although menin is also expressed in hematopoietic lineages, its role in CD8⁺ T cells remains unclear. We generated Menin^flox/flox CD4-Cre (Menin-KO) mice by crossing Menin^flox/flox mice with CD4-Cre transgenic (Tg) mice to determine the role of menin in CD8⁺ T cells. Wild-type (WT) and Menin-KO mice were infected with Listeria monocytogenes expressing OVA to analyze the immune response of Ag-specific CD8⁺ T cells. Menin deficiency resulted in an impaired primary immune response by CD8⁺ T cells. On day 7, there were fewer Menin-KO OVA-specific CD8⁺ T cells compared with WT cells. Next, we adoptively transferred WT and Menin-KO OT-1 Tg CD8⁺ T cells into congenic recipient mice and infected them with L. monocytogenes expressing OVA to determine the CD8⁺ T cell-intrinsic effect. Menin-KO OT-1 Tg CD8⁺ T cells were outcompeted by the WT cells upon infection. Increased expression of Blimp-1 and T-bet, cell cycle inhibitors, and proapoptotic genes was observed in the Menin-KO OT-1 Tg CD8⁺ T cells upon infection. These data suggest that menin inhibits differentiation into terminal effectors and positively controls proliferation and survival of Ag-specific CD8⁺ T cells that are activated upon infection. Collectively, our study uncovered an important role for menin in the immune response of CD8⁺ T cells to infection.

Exercise Training Alleviates Hypoxia-induced Mitochondrial Dysfunction in the Lymphocytes of Sedentary Males

This study elucidates how interval and continuous exercise regimens affect the mitochondrial functionality of lymphocytes under hypoxic stress. Sixty healthy sedentary males were randomly assigned to engage in either high-intensity interval training (HIIT, 3 min intervals at 80% and 40% VO_2max, n = 20) or moderate-intensity continuous training (MICT, sustained 60% VO_2max, n = 20) for 30 min/day, 5 days/week for 6 weeks or were assigned to a control group that did not receive exercise intervention (n = 20). Lymphocyte phenotypes/mitochondrial functionality under hypoxic exercise (HE, 100 W under 12% O₂) were determined before and after the various interventions. Before the intervention, HE (i) increased the mobilization of senescent (CD57⁺/CD28^-) lymphocytes into the blood, (ii) decreased the ATP-linked O₂ consumption rate (OCR), the reserve capacity of OCR, and the citrate synthase activity in the mitochondria, and (iii) lowered the mitochondrial membrane potential (MP) and elevated the matrix oxidant burden (MOB) of lymphocytes. However, both HIIT and MICT significantly (i) decreased blood senescent lymphocyte counts, (ii) enhanced the mitochondrial OCR with increased citrate synthase and succinate dehydrogenase activities, (iii) increased mitochondrial MP and decreased MOB and (iv) increased the ratio of mitofusin to DRP-1 in lymphocytes after HE. Thus, we concluded that either HIIT or MICT effectively improves lymphocyte mitochondrial functionality by enhancing oxidative phosphorylation and suppressing oxidative damage under hypoxic conditions.

Shifts in subsets of CD8+ T-cells as evidence of immunosenescence in patients with cancers affecting the lungs: an observational case-control study

Background

Shifts in CD8+ T-cell subsets that are hallmarks of immunosenescence are observed in ageing and in conditions of chronic immune stimulation. Presently, there is limited documentation of such changes in lung cancer and other malignancies affecting the lungs.

Methods

Changes in CD8+ T-cell subsets, based on the expression of CD28 and CD57, were analysed in patients with various forms of cancer affecting the lungs, undergoing chemotherapy and in a control group over six months, using multi-colour flow cytometry.

Results

The differences between patients and controls, and the changes in the frequency of CD8+ T-cell subpopulations among lung cancer patients corresponded to those seen in immunosenescence: lower CD8-/CD8+ ratio, lower proportions of CD28+CD57- cells consisting of naïve and central memory cells, and higher proportions of senescent-enriched CD28-CD57+ cells among the lung cancer patients, with the stage IV lung cancer patients showing the most pronounced changes. Also observed was a tendency of chemotherapy to induce the formation of CD28+CD57+ cells, which, in line with the capacity of chemotherapy to induce the formation of senescent cells, might provide more evidence supporting CD28+CD57+ cells as senescent cells.

Conclusion

Immunosenescence was present before the start of the treatment; it appeared to be pronounced in patients with advanced cases of malignancies affecting the lungs, and might not be averted by chemotherapy.