The janus head of T cell aging - autoimmunity and immunodeficiency

Inflammaging, immunosenescence, and cardiovascular aging: insights into long COVID implications

Aging leads to physiological changes, including inflammaging-a chronic low-grade inflammatory state with significant implications for various physiological systems, particularly for cardiovascular health. Concurrently, immunosenescence-the age-related decline in immune function, exacerbates vulnerabilities to cardiovascular pathologies in older individuals. Examining the dynamic connections between immunosenescence, inflammation, and cardiovascular aging, this mini-review aims to disentangle some of these interactions for a better understanding of their complex interplay. In the context of cardiovascular aging, the chronic inflammatory state associated with inflammaging compromises vascular integrity and function, contributing to atherosclerosis, endothelial dysfunction, arterial stiffening, and hypertension. The aging immune system's decline amplifies oxidative stress, fostering an environment conducive to atherosclerotic plaque formation. Noteworthy inflammatory markers, such as the high-sensitivity C-reactive protein, interleukin-6, interleukin-1β, interleukin-18, and tumor necrosis factor-alpha emerge as key players in cardiovascular aging, triggering inflammatory signaling pathways and intensifying inflammaging and immunosenescence. In this review we aim to explore the molecular and cellular mechanisms underlying inflammaging and immunosenescence, shedding light on their nuanced contributions to cardiovascular diseases. Furthermore, we explore the reciprocal relationship between immunosenescence and inflammaging, revealing a self-reinforcing cycle that intensifies cardiovascular risks. This understanding opens avenues for potential therapeutic targets to break this cycle and mitigate cardiovascular dysfunction in aging individuals. Furthermore, we address the implications of Long COVID, introducing an additional layer of complexity to the relationship between aging, immunosenescence, inflammaging, and cardiovascular health. Our review aims to stimulate continued exploration and advance our understanding within the realm of aging and cardiovascular health.

Inclusion body myositis, viral infections, and TDP-43: a narrative review

The ubiquitous RNA-processing molecule TDP-43 is involved in neuromuscular diseases such as inclusion body myositis, a late-onset acquired inflammatory myopathy. TDP-43 solubility and function are disrupted in certain viral infections. Certain viruses, high viremia, co-infections, reactivation of latent viruses, and post-acute expansion of cytotoxic T cells may all contribute to inclusion body myositis, mainly in an age-shaped immune landscape. The virally induced senescent, interferon gamma-producing cytotoxic CD8+ T cells with increased inflammatory, and cytotoxic features are involved in the occurrence of inclusion body myositis in most such cases, in a genetically predisposed host. We discuss the putative mechanisms linking inclusion body myositis, TDP-43, and viral infections untangling the links between viruses, interferon, and neuromuscular degeneration could shed a light on the pathogenesis of the inclusion body myositis and other TDP-43-related neuromuscular diseases, with possible therapeutic implications.

Correlations between insulin-degrading enzyme and metabolic markers in patients diagnosed with type 2 diabetes, Alzheimer's disease, and healthy controls: a comparative study

PURPOSE

This study aimed to explore correlations between insulin-degrading enzyme (IDE) and markers of metabolic function in a group of patients diagnosed with type 2 diabetes mellitus (T2DM) or Alzheimer's disease (AD) and metabolically healthy volunteers.

METHOD

We included 120 individuals (47 with T2DM, 9 with AD, and 64 healthy controls). Serum levels of IDE were measured with commercial kits for ELISA. Differences in IDE levels between groups were analyzed with non-parametric ANCOVA, and correlations were analyzed with Spearman's rank correlations. We also investigated the influence of age, sex, and the use of insulin on the correlation using a non-parametric version of partial correlation.

RESULTS

Patients diagnosed with T2DM had higher IDE levels than patients diagnosed with AD and healthy controls after adjustment for age and sex. IDE was increasingly associated with body mass index (BMI), fasting blood glucose, C-peptide, hemoglobin A1c (HbA1c), insulin resistance, and triglycerides. In stratified analyses, we found a decreasing partial correlation between IDE and HbA1c in patients diagnosed with AD and a decreasing partial correlation between IDE and C-peptide in healthy controls. In patients diagnosed with T2DM, we found no partial correlations.

CONCLUSION

These results indicate that IDE is essential in metabolic function and might reflect metabolic status, although it is not yet a biomarker that can be utilized in clinical practice. Further research on IDE in human blood may provide crucial insights into the full function of the enzyme.

Adaptive immunity and atherosclerosis: aging at its crossroads

Adaptive immunity plays a profound role in atherosclerosis pathogenesis by regulating antigen-specific responses, inflammatory signaling and antibody production. However, as we age, our immune system undergoes a gradual functional decline, a phenomenon termed "immunosenescence". This decline is characterized by a reduction in proliferative naïve B- and T cells, decreased B- and T cell receptor repertoire and a pro-inflammatory senescence associated secretory profile. Furthermore, aging affects germinal center responses and deteriorates secondary lymphoid organ function and structure, leading to impaired T-B cell dynamics and increased autoantibody production. In this review, we will dissect the impact of aging on adaptive immunity and the role played by age-associated B- and T cells in atherosclerosis pathogenesis, emphasizing the need for interventions that target age-related immune dysfunction to reduce cardiovascular disease risk.

Accelerated biological aging as a potential risk factor for rheumatoid arthritis

OBJECTS

Previous studies have suggested a potential correlation between rheumatoid arthritis (RA) and biological aging, but the intricate connections and mechanisms remain elusive.

METHODS

In our study, we focused on two specific measures of biological age (PhenoAge and BioAge), which are derived from clinical biomarkers. The residuals of these measures, when compared to chronological age, are defined as biological age accelerations (BAAs). Utilizing the extensive UK Biobank dataset along with various genetic datasets, we conducted a thorough assessment of the relationship between BAAs and RA at both the individual and aggregate levels.

RESULTS

Our observational studies revealed positive correlations between the two BAAs and the risk of developing both RA and seropositive RA. Furthermore, the genetic risk score (GRS) for PhenoAgeAccel was associated with an increased risk of RA and seropositive RA. Linkage disequilibrium score regression (LDSC) analysis further supported these findings, revealing a positive genetic correlation between PhenoAgeAccel and RA. PLACO analysis identified 38 lead pleiotropic single nucleotide polymorphisms linked to 301 genes, providing valuable insights into the potential mechanisms connecting PhenoAgeAccel and RA.

CONCLUSION

In summary, our study has successfully revealed a positive correlation between accelerated biological aging, as measured by BAAs, and the susceptibility to RA.

Single-cell profiling reveals age-associated immunity in atherosclerosis

AIMS

Aging is a dominant driver of atherosclerosis and induces a series of immunological alterations, called immunosenescence. Given the demographic shift towards elderly, elucidating the unknown impact of aging on the immunological landscape in atherosclerosis is highly relevant. While the young Western diet-fed Ldlr-deficient (Ldlr-/-) mouse is a widely used model to study atherosclerosis, it does not reflect the gradual plaque progression in the context of an aging immune system as occurs in humans.

METHODS AND RESULTS

Here, we show that aging promotes advanced atherosclerosis in chow diet-fed Ldlr-/- mice, with increased incidence of calcification and cholesterol crystals. We observed systemic immunosenescence, including myeloid skewing and T-cells with more extreme effector phenotypes. Using a combination of single-cell RNA-sequencing and flow cytometry on aortic leucocytes of young vs. aged Ldlr-/- mice, we show age-related shifts in expression of genes involved in atherogenic processes, such as cellular activation and cytokine production. We identified age-associated cells with pro-inflammatory features, including GzmK+CD8+ T-cells and previously in atherosclerosis undefined CD11b+CD11c+T-bet+ age-associated B-cells (ABCs). ABCs of Ldlr-/- mice showed high expression of genes involved in plasma cell differentiation, co-stimulation, and antigen presentation. In vitro studies supported that ABCs are highly potent antigen-presenting cells. In cardiovascular disease patients, we confirmed the presence of these age-associated T- and B-cells in atherosclerotic plaques and blood.

CONCLUSIONS

Collectively, we are the first to provide comprehensive profiling of aged immunity in atherosclerotic mice and reveal the emergence of age-associated T- and B-cells in the atherosclerotic aorta. Further research into age-associated immunity may contribute to novel diagnostic and therapeutic tools to combat cardiovascular disease.

From aging to long COVID: exploring the convergence of immunosenescence, inflammaging, and autoimmunity

The process of aging is accompanied by a dynamic restructuring of the immune response, a phenomenon known as immunosenescence. This mini-review navigates through the complex landscape of age-associated immune changes, chronic inflammation, age-related autoimmune tendencies, and their potential links with immunopathology of Long COVID. Immunosenescence serves as an introductory departure point, elucidating alterations in immune cell profiles and their functional dynamics, changes in T-cell receptor signaling, cytokine network dysregulation, and compromised regulatory T-cell function. Subsequent scrutiny of chronic inflammation, or "inflammaging," highlights its roles in age-related autoimmune susceptibilities and its potential as a mediator of the immune perturbations observed in Long COVID patients. The introduction of epigenetic facets further amplifies the potential interconnections. In this compact review, we consider the dynamic interactions between immunosenescence, inflammation, and autoimmunity. We aim to explore the multifaceted relationships that link these processes and shed light on the underlying mechanisms that drive their interconnectedness. With a focus on understanding the immunological changes in the context of aging, we seek to provide insights into how immunosenescence and inflammation contribute to the emergence and progression of autoimmune disorders in the elderly and may serve as potential mediator for Long COVID disturbances.

Risk factors for multiple sclerosis in the context of Epstein-Barr virus infection

Compelling evidence indicates that Epstein Barr virus (EBV) infection is a prerequisite for multiple sclerosis (MS). The disease may arise from a complex interplay between latent EBV infection, genetic predisposition, and various environmental and lifestyle factors that negatively affect immune control of the infection. Evidence of gene-environment interactions and epigenetic modifications triggered by environmental factors in genetically susceptible individuals supports this view. This review gives a short introduction to EBV and host immunity and discusses evidence indicating EBV as a prerequisite for MS. The role of genetic and environmental risk factors, and their interactions, in MS pathogenesis is reviewed and put in the context of EBV infection. Finally, possible preventive measures are discussed based on the findings presented.

Senescent T cells: Beneficial and detrimental roles

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

Effect of Age and Sex on Gene Expression-Based Radiation Biodosimetry Using Mouse Peripheral Blood

Blood-based gene expression profiles that can reconstruct radiation exposure are being developed as a practical approach to radiation biodosimetry. However, age and sex could potentially limit the accuracy of the approach. In this study, we determined the impact of age on the peripheral blood cell gene expression profile of female mice exposed to radiation and identified differences and similarities with a previously obtained transcriptomic signature of male mice. Young (2 months) and old (24 months) female mice were irradiated with 4 Gy X-rays, total RNA was isolated from blood 24 hours later and subjected to whole-genome microarray analysis. Dose reconstruction analyses using a gene signature trained on gene expression data from irradiated young male mice showed accurate reconstruction of 0 or 4 Gy doses with root mean square error of ±0.75 Gy (R2 = 0.90) in young female mice. Although dose reconstruction for irradiated old female mice was less accurate than young female mice, the deviation from the actual radiation dose was not statistically significant. Pathway analysis of differentially expressed genes revealed that after irradiation, apoptosis-related functions were overrepresented, whereas functions related to quantities of various immune cell subtypes were underrepresented, among differentially expressed genes from young female mice, but not older animals. Furthermore, young mice significantly upregulated genes involved in phagocytosis, a process that eliminates apoptotic cells and preserves tissue homeostasis. Both functions were also overrepresented in young, but not old, male mice following 4 Gy X-irradiation. Lastly, functions associated with neutrophil activation that is essential for killing invading pathogens and regulating the inflammatory response were predicted to be uniquely enriched in young but not old female mice. This work supports the concept that peripheral blood gene expression profiles can be identified in mice that accurately predict physical radiation dose exposure irrespective of age and sex.

Vitamin D as a Shield against Aging

Aging can be seen as a physiological progression of biomolecular damage and the accumulation of defective cellular components, which trigger and amplify the process, toward whole-body function weakening. Senescence initiates at the cellular level and consists in an inability to maintain homeostasis, characterized by the overexpression/aberrant expression of inflammatory/immune/stress responses. Aging is associated with significant modifications in immune system cells, toward a decline in immunosurveillance, which, in turn, leads to chronic elevation of inflammation/oxidative stress, increasing the risk of (co)morbidities. Albeit aging is a natural and unavoidable process, it can be regulated by some factors, like lifestyle and diet. Nutrition, indeed, tackles the mechanisms underlying molecular/cellular aging. Many micronutrients, i.e., vitamins and elements, can impact cell function. This review focuses on the role exerted by vitamin D in geroprotection, based on its ability to shape cellular/intracellular processes and drive the immune response toward immune protection against infections and age-related diseases. To this aim, the main biomolecular paths underlying immunosenescence and inflammaging are identified as biotargets of vitamin D. Topics such as heart and skeletal muscle cell function/dysfunction, depending on vitamin D status, are addressed, with comments on hypovitaminosis D correction by food and supplementation. Albeit research has progressed, still limitations exist in translating knowledge into clinical practice, making it necessary to focus attention on the role of vitamin D in aging, especially considering the growing number of older individuals.

Efficacy and Clinical Significance of the Zuogui Pill on Premature Ovarian Failure via the GDF-9/Smad2 Pathway

Our study aims to investigate the efficacy and clinical significance of the Zuogui pill (ZGP) on premature ovarian failure (POF) via the GDF-9/Smad2 pathway. Changes in clinical symptoms in the control group (treated with Femoston alone) and the treatment group (treated with ZGP combined with Femoston) were assessed before and after treatment. Sex hormone levels, serum inflammatory cytokine levels, and ultrasound parameters were measured before and after treatment. POF rat models were established using cyclophosphamide and the POF rats were treated with Femoston, or ZGP combined with Femoston. GDF-9 and Smad2 expression levels were determined by RT-qPCR. The follicle-stimulating hormone (FSH), luteinizing hormone (LH), interleukin (IL)-6, and IL-21 levels, and the pulsatility index (PI) and resistance index (RI) values were decreased, while the estradiol (E2) and anti-Mullerian hormone (AMH) levels, antral follicle count (AFC), ovarian volume (OV), mean ovarian diameter (MOD), and peak systolic velocity (PSV) values were increased in the treatment group compared to the control group. After treatment with ZGP combined with Femoston, GDF-9 and Smad2 expression in the ovarian tissues of POF rats increased. ZGP has a therapeutic effect on POF via modulation of the GDF-9/Smad2 pathway.

The detectable anti-interferon-γ autoantibodies in COVID-19 patients may be associated with disease severity

BACKGROUND

Neutralizing anti-interferon (IFN)-γ autoantibodies are linked to adult-onset immunodeficiency and opportunistic infections.

METHODS

To explore whether anti-IFN-γ autoantibodies are associated with disease severity of coronavirus disease 2019 (COVID-19), we examined the titers and functional neutralization of anti-IFN-γ autoantibodies in COVID-19 patients. In 127 COVID-19 patients and 22 healthy controls, serum titers of anti-IFN-γ autoantibodies were quantified using enzyme-linked immunosorbent assay, and the presence of autoantibodies was verified with immunoblotting assay. The neutralizing capacity against IFN-γ was evaluated with flow cytometry analysis and immunoblotting, and serum cytokines levels were determined using the MULTIPLEX platform.

RESULTS

A higher proportion of severe/critical COVID-19 patients had positivity for anti-IFN-γ autoantibodies (18.0%) compared with non-severe patients (3.4%, p < 0.01) or healthy control (HC) (0.0%, p < 0.05). Severe/critical COVID-19 patients also had higher median titers of anti-IFN-γ autoantibodies (5.01) compared with non-severe patients (1.33) or HC (0.44). The immunoblotting assay could verify the detectable anti-IFN-γ autoantibodies and revealed more effective inhibition of signal transducer and activator of transcription (STAT1) phosphorylation on THP-1 cells treated with serum samples from anti-IFN-γ autoantibodies-positive patients compared with those from HC (2.21 ± 0.33 versus 4.47 ± 1.64, p < 0.05). In flow-cytometry analysis, sera from autoantibodies-positive patients could also significantly more effectively suppress the STAT1 phosphorylation (median,67.28%, interquartile range [IQR] 55.2-78.0%) compared with serum from HC (median,106.7%, IQR 100.0-117.8%, p < 0.05) or autoantibodies-negative patients (median,105.9%, IQR 85.5-116.3%, p < 0.05). Multivariate analysis revealed that the positivity and titers of anti-IFN-γ autoantibodies were significant predictors of severe/critical COVID-19. Compared with non-severe COVID-19 patients, we reveal that a significantly higher proportion of severe/critical COVID-19 patients are positive for anti-IFN-γ autoantibodies with neutralizing capacity.

CONCLUSION

Our results would add COVID-19 to the list of diseases with the presence of neutralizing anti-IFN-γ autoAbs. Anti-IFN-γ autoantibodies positivity is a potential predictor of severe/critical COVID-19.

Age-related changes in CD4+ T and NK cell compartments may contribute to the occurrence of pregnancy loss in advanced maternal age

A recent study characterized novel immune cell subsets (T, NK, and γδ T cell subsets) related to recurrent pregnancy loss (RPL). This study aims to assess whether these RPL-related immune cell subsets are affected by aging. The percentages of peripheral blood immunes cells from nulligravida women (NGW), women with a history of normal pregnancy (NP), and women with a history of pregnancy loss (PL) were detected by flow cytometry. The correlations between maternal age and cell percentages were assessed. We found a significant positive correlation between PL and maternal age. The percentages of effector memory CD4⁺ T (CD3⁺ CD4⁺ CD45RA¯ CCR7¯), terminally differentiated CD4⁺ T (CD3⁺ CD4⁺ CD45RA⁺ CCR7¯), and mature NK cells (CD3¯ CD56^+lo) significantly increased with maternal age. A significant decrease in the percentage of Naïve CD4⁺ T cells (CD3⁺ CD4⁺ CD45RA⁺ CCR7⁺) with age was observed in women from the NP group. Women aged 35 or older had significantly higher percentages of effector memory CD4⁺ T cells, terminally differentiated CD4⁺ T cells, and mature NK cells than younger women. Maternal age positively correlates with terminally differentiated CD4⁺ T, effector memory CD4⁺ T, and mature NK cell percentages. In contrast, an inverse correlation was observed between Naïve CD4⁺ T cell and age among women from the NP group. Our findings indicate that age-related CD4⁺ T and NK cell dysregulation might be involved in the pathogenesis of PL in women with advanced maternal age. The underlying mechanism needs further investigation.

Cartilage organoids for cartilage development and cartilage-associated disease modeling

Cartilage organoids have emerged as powerful modelling technology for recapitulation of joint embryonic events, and cartilage regeneration, as well as pathophysiology of cartilage-associated diseases. Recent breakthroughs have uncovered "mini-joint" models comprising of multicellular components and extracellular matrices of joint cartilage for development of novel disease-modifying strategies for personalized therapeutics of cartilage-associated diseases. Here, we hypothesized that LGR5-expressing embryonic joint chondroprogenitor cells are ideal stem cells for the generation of cartilage organoids as "mini-joints" ex vivo "in a dish" for embryonic joint development, cartilage repair, and cartilage-associated disease modelling as essential research models of drug screening for further personalized regenerative therapy. The pilot research data suggested that LGR5-GFP-expressing embryonic joint progenitor cells are promising for generation of cartilage organoids through gel embedding method, which may exert various preclinical and clinical applications for realization of personalized regenerative therapy in the future.

Toll-like receptors and NLRP3 inflammasome-dependent pathways in Parkinson's disease: mechanisms and therapeutic implications

Parkinson's disease (PD) is a chronic progressive neurodegenerative disorder characterized by motor and non-motor disturbances as a result of a complex and not fully understood pathogenesis, probably including neuroinflammation, oxidative stress, and formation of alpha-synuclein (α-syn) aggregates. As age is the main risk factor for several neurodegenerative disorders including PD, progressive aging of the immune system leading to inflammaging and immunosenescence may contribute to neuroinflammation leading to PD onset and progression; abnormal α-syn aggregation in the context of immune dysfunction may favor activation of nucleotide-binding oligomerization domain-like receptor (NOD) family pyrin domain containing 3 (NLRP3) inflammasome within microglial cells through interaction with toll-like receptors (TLRs). This process would further lead to activation of Caspase (Cas)-1, and increased production of pro-inflammatory cytokines (PC), with subsequent impairment of mitochondria and damage to dopaminergic neurons. All these phenomena are mediated by the translocation of nuclear factor kappa-B (NF-κB) and enhanced by reactive oxygen species (ROS). To date, drugs to treat PD are mainly aimed at relieving clinical symptoms and there are no disease-modifying options to reverse or stop disease progression. This review outlines the role of the TLR/NLRP3/Cas-1 pathway in PD-related immune dysfunction, also focusing on specific therapeutic options that might be used since the early stages of the disease to counteract neuroinflammation and immune dysfunction.

Impaired CD4+ T cell response in older adults is associated with reduced immunogenicity and reactogenicity of mRNA COVID-19 vaccination

Whether age-associated defects in T cells impact the immunogenicity and reactogenicity of mRNA vaccines remains unclear. Using a vaccinated cohort (n = 216), we demonstrated that older adults (aged ≥65 years) had fewer vaccine-induced spike-specific CD4⁺ T cells including CXCR3⁺ circulating follicular helper T cells and the T_H1 subset of helper T cells after the first dose, which correlated with their lower peak IgG levels and fewer systemic adverse effects after the second dose, compared with younger adults. Moreover, spike-specific T_H1 cells in older adults expressed higher levels of programmed cell death protein 1, a negative regulator of T cell activation, which was associated with low spike-specific CD8⁺ T cell responses. Thus, an inefficient CD4⁺ T cell response after the first dose may reduce the production of helper T cytokines, even after the second dose, thereby lowering humoral and cellular immunity and reducing systemic reactogenicity. Therefore, enhancing CD4⁺ T cell response following the first dose is key to improving vaccine efficacy in older adults.

Assessing the association of leukocyte telomere length with ankylosing spondylitis and rheumatoid arthritis: A bidirectional Mendelian randomization study

Background

Telomere length shortening can cause senescence and apoptosis in various immune cells, resulting in immune destabilization and ageing of the organism. In this study, we aimed to systematically assess the causal relationship of leukocyte telomere length (LTL) with ankylosing spondylitis (AS) and rheumatoid arthritis (RA) using a Mendelian randomization study.

Methods

LTL (n=472174) was obtained from the UK Biobank genome-wide association study pooled data. AS (n=229640), RA (n=212472) were obtained from FinnGen database. MR-Egger, inverse variance weighting, and weighted median methods were used to estimate the effects of causes. Cochran's Q test, MR Egger intercept test, MR-PRESSO, leave-one-out analysis, and funnel plots were used to look at sensitivity, heterogeneity, and multiple effects. Forward MR analysis considered LTL as the exposure and AS, RA as the outcome. Reverse MR analysis considered AS, RA as the exposure and LTL as the outcome.

Results

In the forward MR analysis, inverse variance-weighted and weighted median analysis results indicated that longer LTL might be associated with increased risk of AS (IVW: OR = 1.55, 95% CI: 1.14-2.11, p = 0.006). MR Egger regression analysis showed no pleiotropy between instrumental variables (IVs) (Egger intercept= 0.008, p = 0.294). The leave-one-out analysis showed that each single nucleotide polymorphism (SNP) of AS was robust to each outcome. No significant causal effects were found between AS, RA and LTL in the reverse MR analysis.

Conclusion

Longer LTL may be related with an increased risk of developing AS, and these findings provide a foundation for future clinical research on the causal association between LTL and AS.

Inflammation and immune dysfunction in Parkinson disease

Parkinson disease (PD) is a progressive neurodegenerative disease that affects peripheral organs as well as the central nervous system and involves a fundamental role of neuroinflammation in its pathophysiology. Neurohistological and neuroimaging studies support the presence of ongoing and end-stage neuroinflammatory processes in PD. Moreover, numerous studies of peripheral blood and cerebrospinal fluid from patients with PD suggest alterations in markers of inflammation and immune cell populations that could initiate or exacerbate neuroinflammation and perpetuate the neurodegenerative process. A number of disease genes and risk factors have been identified as modulators of immune function in PD and evidence is mounting for a role of viral or bacterial exposure, pesticides and alterations in gut microbiota in disease pathogenesis. This has led to the hypothesis that complex gene-by-environment interactions combine with an ageing immune system to create the 'perfect storm' that enables the development and progression of PD. We discuss the evidence for this hypothesis and opportunities to harness the emerging immunological knowledge from patients with PD to create better preclinical models with the long-term goal of enabling earlier identification of at-risk individuals to prevent, delay and more effectively treat the disease.

Aging and CMV Infection Affect Pre-existing SARS-CoV-2-Reactive CD8+ T Cells in Unexposed Individuals

Age is a major risk factor for COVID-19 severity, and T cells play a central role in anti-SARS-CoV-2 immunity. Because SARS-CoV-2-cross-reactive T cells have been detected in unexposed individuals, we investigated the age-related differences in pre-existing SARS-CoV-2-reactive T cells. SARS-CoV-2-reactive CD4⁺ T cells from young and elderly individuals were mainly detected in the central memory fraction and exhibited similar functionalities and numbers. Naïve-phenotype SARS-CoV-2-reactive CD8⁺ T cell populations decreased markedly in the elderly, while those with terminally differentiated and senescent phenotypes increased. Furthermore, senescent SARS-CoV-2-reactive CD8⁺ T cell populations were higher in cytomegalovirus seropositive young individuals compared to seronegative ones. Our findings suggest that age-related differences in pre-existing SARS-CoV-2-reactive CD8⁺ T cells may explain the poor outcomes in elderly patients and that cytomegalovirus infection is a potential factor affecting CD8⁺ T cell immunity against SARS-CoV-2. Thus, this study provides insights for developing effective therapeutic and vaccination strategies for the elderly.

HLA-DR+ CD45RA- Tregs and CD28- Treg-like cells: Potential immunologic biomarkers for reproductive aging

PROBLEM

This study aimed to identify subsets of regulatory T cells (Tregs) associated with ovarian aging and determine whether they can be used as markers of reproductive aging.

METHOD

This prospective cohort study was conducted among women of reproductive age. Basic physiological characteristics, reproductive hormones, Treg cell subsets, and correlations between these parameters were assessed. The POSEIDON criteria was used to identify women with low reproductive potential.

RESULTS

The percentages of HLA-DR⁺ CD45RA- Tregs and CD28- Treg-like cells significantly increased with age. Women between 40 and 49 years had significantly higher percentages of HLA-DR⁺ CD45RA- Tregs and CD28- Treg-like cells than those at 20-29, 30-34, and 35-39 years old. Age positively correlated with FSH levels and the percentages of HLA-DR⁺ CD45RA- Tregs and CD28- Treg-like cells, but inversely correlated with antral follicle count (AFC) and AMH levels. Interestingly, a positive correlation was found between the percentages of HLA-DR⁺ CD45RA- Tregs and FSH levels, whereas an inverse correlation was found between those of HLA-DR⁺ CD45RA- Tregs and AFC or AMH levels. Furthermore, a significant positive correlation was observed between the percentages of CD28- Treg-like cells and AFC. Based on POSEIDON criteria, women with the percentages of HLA-DR⁺ CD45RA- Tregs and CD28- Treg-like cells above reference value ranges were assigned to the low prognosis groups.

CONCLUSION

These findings suggest that HLA-DR⁺ CD45RA- Tregs and CD28- Treg-like cells can be used as immunologic markers of reproductive aging, which helps clinicians identify women with low reproductive potential and establish individualized therapeutic strategies. This article is protected by copyright. All rights reserved.

Influence of immunohematological markers on severity of in vivo hemolysis in human warm autoimmune haemolytic anemia

Autoantibody production in autoimmune haemolytic anemia (AIHA) is the result of the loss of self-immunological tolerance of the host. Here we investigated the various immunohematological markers that may influence the severity of in vivo hemolysis in warm AIHA (WAIHA). Complete direct antiglobulin test (DAT) evaluation and immunohematological characterization were performed in 247 patients of WAIHA following departmental protocols. Clinical and laboratory details of patients were obtained from patient file. The median age of WAIHA patients was 47 years with a female preponderance. Lymphoproliferative diseases were the major underlying causes of secondary WAIHA. The mean haemoglobin (Hb) and reticulocyte count (Retic) were 6.43 gm/dL and 7.58% respectively. Single autoantibody bound to red cells was investigated in 151 patients. The main IgG subclass was IgG1. Multiple autoantibodies like IgG+ C, IgG+IgA and IgG+IgA+C were found in 87 (35.2%) patients. Free autoantibodies were observed in 112 patients with a median indirect antiglobulin test (IAT) reactivity of 2+. Derangement of haematological and biochemical values was statistically significant with increase in DAT reactivity, presence of multiple autoantibodies on red cells, coating of red cells by IgG3 or multiple IgG subclass, higher DAT dilution and increasing IAT reactivity. We conclude that several important but simple immunohematological parameters may influence the degree of in vivo hemolysis in WAIHA. Since a set of common haematological and biochemical test determines the severity of in vivo hemolysis therefore a comprehensive clinical and immunohematological evaluation is advisable for a correct diagnostic and therapeutic workup of WAIHA.

Clinical perspectives on the age-related increase of immunosuppressive activity

The aging process is associated with a remodeling of the immune system involving chronic low-grade inflammation and a gradual decline in the function of the immune system. These processes are also called inflammaging and immunosenescence. The age-related immune remodeling is associated with many clinical changes, e.g., risk for cancers and chronic infections increases, whereas the efficiency of vaccination and immunotherapy declines with aging. On the other hand, there is convincing evidence that chronic inflammatory states promote the premature aging process. The inflammation associated with aging or chronic inflammatory conditions stimulates a counteracting immunosuppression which protects tissues from excessive inflammatory injuries but promotes immunosenescence. Immunosuppression is a driving force in tumors and chronic infections and it also induces the tolerance to vaccination and immunotherapies. Immunosuppressive cells, e.g., myeloid-derived suppressor cells (MDSC), regulatory T cells (Treg), and type M2 macrophages, have a crucial role in tumorigenesis and chronic infections as well as in the tolerance to vaccination and immunotherapies. Interestingly, there is substantial evidence that inflammaging is also associated with an increased immunosuppressive activity, e.g., upregulation of immunosuppressive cells and anti-inflammatory cytokines. Given that both the aging and chronic inflammatory states involve the activation of immunosuppression and immunosenescence, this might explain why aging is a risk factor for tumorigenesis and chronic inflammatory states and conversely, chronic inflammatory insults promote the premature aging process in humans.

Molecular Mechanisms of Immunosenescene and Inflammaging: Relevance to the Immunopathogenesis and Treatment of Multiple Sclerosis

Aging is characterized, amongst other features, by a complex process of cellular senescence involving both innate and adaptive immunity, called immunosenescence and associated to inflammaging, a low-grade chronic inflammation. Both processes fuel each other and partially explain increasing incidence of cancers, infections, age-related autoimmunity, and vascular disease as well as a reduced response to vaccination. Multiple sclerosis (MS) is a lifelong disease, for which considerable progress in disease-modifying therapies (DMTs) and management has improved long-term survival. However, disability progression, increasing with age and disease duration, remains. Neurologists are now involved in caring for elderly MS patients, with increasing comorbidities. Aging of the immune system therefore has relevant implications for MS pathogenesis, response to DMTs and the risks mediated by these treatments. We propose to review current evidence regarding markers and molecular mechanisms of immunosenescence and their relevance to understanding MS pathogenesis. We will focus on age-related changes in the innate and adaptive immune system in MS and other auto-immune diseases, such as systemic lupus erythematosus and rheumatoid arthritis. The consequences of these immune changes on MS pathology, in interaction with the intrinsic aging process of central nervous system resident cells will be discussed. Finally, the impact of immunosenescence on disease evolution and on the safety and efficacy of current DMTs will be presented.

In-hospital blood collection increases the rate of indeterminate results in interferon-gamma release assays

Background:

The interferon (IFN)-γ release assay (IGRA) has recently been established as a method to evaluate the infection status of tuberculosis instead of the tuberculin skin test. However, indeterminate results can create challenges to interpretation. The IGRA has been available in Japan since 2005, including the recently launched QuantiFERON-TB Gold Plus (QFT-plus) assay.

Objectives:

The aim of this study was to investigate the clinical features and predictors of indeterminate results by the QFT-plus test in routine practice.

Methods:

This was a cross-sectional study of 1258 patients. Multivariate logistic regression models were employed to investigate the clinical factors related to indeterminate results by the QFT-plus.

Results:

Overall, 91.8% of results were found to be conclusive and 8.2% were indeterminate. The QFT-plus indeterminate results were predominantly due to a low level of IFN-γ production by mitogens. Multivariate analysis indicated that an indeterminate result was significantly associated with age, sex, corticosteroid use, autoimmune disease, and inpatient setting.

Conclusion:

Certain types of individuals are at higher risk of an indeterminate IGRA result. The QFT-plus test for hospitalized patients should be avoided as much as possible, and it is better to perform the test for those patients in outpatient settings.

Deep immune phenotyping reveals similarities between aging, Down syndrome, and autoimmunity

[Figure: see text].

Development of Myeloperoxidase Anti-neutrophil Cytoplasmic Antibody-positive Necrotizing Crescentic Glomerulonephritis in an Elderly Patient with Immunological Kidney Disease

A 78-year-old man presented with hypercalcemia and renal disease with high serum IgG4 and positive myeloperoxidase anti-neutrophil cytoplasmic antibody (MPO-ANCA), exhibiting sarcoidosis-like chest findings. A renal biopsy revealed tubulointerstitial nephritis, membranous nephropathy (MN), and sub-capsular lymphoid aggregates without fulfilling the diagnostic criteria of IgG4-related disease or sarcoidosis. Steroid therapy ameliorated the serological and renal abnormalities. After 5 years, following gradual increases in the neutrophil count and upper respiratory infection (URI), necrotizing crescentic glomerulonephritis (NCGN) developed with an increased serum MPO-ANCA level. These results suggest that in the presence of MPO-ANCA in immune senescence, the persistent neutrophil increase with URI may lead to the development of NCGN.

Impact of Patient Age on Clinical Efficacy and Toxicity of Checkpoint Inhibitor Therapy

The addition of immune checkpoint inhibitors (ICIs) to the therapeutic armamentarium for solid malignancies has resulted in unprecedented improvements in patient outcomes in many cancers. The landscape of ICIs continues to evolve with novel approaches such as dual immune checkpoint blockade and combination therapies with other anticancer agents including cytotoxic chemotherapies and/or antiangiogenics. However, there is significant heterogeneity seen in antitumor responses, with certain patients deriving durable benefit, others experiencing initial benefit followed by acquired resistance necessitating change in therapy, and still others who are primarily refractory to ICIs. While generally better tolerated than traditional cytotoxic chemotherapy, ICIs are associated with unique toxicities, termed immune-related adverse events (irAEs), which can be severe or even lethal. As a disease of aging, older individuals make up a large proportion of patients diagnosed with cancer, yet this population is often underrepresented in clinical trials. Because ICIs indirectly target malignant cells through T cell activation, it has been hypothesized that age-related changes to the immune system may impact the efficacy and toxicity of these drugs. In this review, we discuss differences in the clinical efficacy and toxicity of ICIs in patients at the extremes of age.

Induction of T Cell Senescence by Cytokine Induced Bystander Activation

As people around the world continue to live longer, maintaining a good quality of life is of increasing importance. The COVID-19 pandemic revealed that the elderly are disproportionally vulnerable to infectious diseases and Immunosenescence plays a critical role in that. An ageing immune system influences the conventional activity of T cells which are at the forefront of eliminating harmful foreign antigens. With ageing, unconventional end-stage T cells, that exhibit a senescent phenotype, amass. These senescent T cells deviate from T cell receptor (TCR) signaling toward natural killer (NK) activity. The transition toward innate immune cell function from these adaptor T cells impacts antigen specificity, contributing to increased susceptibility of infection in the elderly. The mechanism by which senescent T cells arise remains largely unclear however in this review we investigate the part that bystander activation plays in driving the change in function of T cells with age. Cytokine-induced bystander activation may offer a plausible explanation for the induction of NK-like activity and senescence in T cells. Further understanding of these specific NK-like senescent T cells allows us to identify the benefits and detriments of these cells in health and disease which can be utilized or regulated, respectively. This review discusses the dynamic of senescent T cells in adopting NK-like T cells and the implications that has in an infectious disease context, predominately in the elderly.

Very late onset neuromyelitis optica spectrum disorders

BACKGROUND AND PURPOSE

Neuromyelitis optica spectrum disorder (NMOSD) often presents in the elderly with an insidious onset of symptoms and aggressive progression. There have been anecdotal cases of very late onset (VLO)-NMOSD, but case series reports are rare. The aim of this retrospective study was to clarify the clinical features of VLO-NMOSD.

METHODS

According to the age at onset, we classified patients with NMOSD into three subgroups: ≤49 years, early onset NMOSD (EO-NMOSD); 50-69 years, late onset NMOSD (LO-NMOSD); and ≥70 years, VLO-NMOSD. We evaluated the clinical characteristics, magnetic resonance imaging (MRI) findings, laboratory data, and immunotherapies of the groups.

RESULTS

Overall, 12 men and 64 women with a median (interquartile range) age at onset and duration of disease of 42.0 (29.0-55.8) years and 70.0 (16.3-143.0) months, respectively, were included. Eight (11%) patients had VLO-NMOSD, 22 (29%) had LO-NMOSD, and 46 (61%) had EO-NMOSD. Patients with EO-NMOSD had a significantly longer interval between episodes as well as time between the first symptom and diagnosis of NMOSD than did those with VLO-NMOSD and LO-NMOSD (p = 0.046). Optic neuritis and nerve lesions on MRI were significantly less frequent in patients with VLO-NMOSD than in those with LO-NMOSD and EO-NMOSD (p = 0.002 and p = 0.028, respectively). In contrast, patients with VLO-NMOSD had higher nadir Expanded Disability Status Scale and Nurick scale scores and a significantly longer spinal lesion length than did those with LO-NMOSD and EO-NMOSD (p = 0.029, p = 0.049, and p = 0.032, respectively).

CONCLUSIONS

Patients with VLO-NMOSD tend to develop severe myelitis with long cord lesions but not optic neuritis.

Decreased Peripheral Naïve T Cell Number and Its Role in Predicting Cardiovascular and Infection Events in Hemodialysis Patients

Patients with end-stage renal disease (ESRD) are at high risk of morbidity and mortality from cardiovascular and infectious diseases, which have been found to be associated with a disturbed immune response. Accelerated T-cell senescence is prevalent in these patients and considered a significant factor contributing to increased risk of various morbidities. Nevertheless, few studies have explicated the relevance of T-cell senescence to these fatal morbidities in ESRD patients. In this study, we designed a longitudinal prospective study to evaluate the influence of T-cell senescence on cardiovascular events (CVEs) and infections in hemodialysis (HD) patients. Clinical outcomes of 404 patients who had been on HD treatment for at least 6 months were evaluated with respect to T-cell senescence determined using flow cytometry. We found that T-cell senescence was associated with systemic inflammation. High-sensitivity C-reactive protein was positively associated with decreased naïve T cell levels. Elevated tumor necrosis factor-α and interleukin 6 levels were significantly associated with lower central memory T cell and higher T effector memory CD45RA cell levels. Decreased CD4⁺ naïve T cell count was independently associated with CVEs, whereas decreased CD8⁺ naïve T cell count was independently associated with infection episodes in HD patients. In conclusion, HD patients exhibited accelerated T-cell senescence, which was positively related to inflammation. A reduction of naïve T cell could be a strong predictor of CVEs and infection episodes in HD patients.

Chemokines Up-Regulated in Epithelial Cells Control Senescence-Associated T Cell Accumulation in Salivary Glands of Aged and Sjögren's Syndrome Model Mice

Immunosenescence is characterized by age-associated changes in immunological functions. Although age- and autoimmune-related sialadenitis cause dry mouth (xerostomia), the roles of immunosenescence and cellular senescence in the pathogenesis of sialadenitis remain unknown. We demonstrated that acquired immune cells rather than innate immune cells infiltrated the salivary glands (SG) of aged mice. An analysis of isolated epithelial cells from SG revealed that the expression levels of the chemokine CXCL13 were elevated in aged mice. Senescence-associated T cells (SA-Ts), which secrete large amounts of atypical pro-inflammatory cytokines, are involved in the pathogenesis of metabolic disorders and autoimmune diseases. The present results showed that SA-Ts and B cells, which express the CXCL13 receptor CXCR5, accumulated in the SG of aged mice, particularly females. CD4⁺ T cells derived from aged mice exhibited stronger in vitro migratory activity toward CXCL13 than those from young mice. In a mouse model of Sjögren’s syndrome (SS), SA-Ts also accumulated in SG, presumably via CXCL12-CXCR4 signaling. Collectively, the present results indicate that SA-Ts accumulate in SG, contribute to the pathogenesis of age- and SS-related sialadenitis by up-regulating chemokines in epithelial cells, and have potential as therapeutic targets for the treatment of xerostomia caused by these types of sialadenitis.

Genetic and Environmental Factors in Parkinson's Disease Converge on Immune Function and Inflammation

Idiopathic Parkinson's disease (iPD) is a movement disorder characterized by the degeneration of dopaminergic neurons and aggregation of the protein α-synuclein. Patients with iPD vary in age of symptom onset, rate of progression, severity of motor and non-motor symptoms, and extent of central and peripheral inflammation. Genetic and environmental factors are believed to act synergistically in iPD pathogenesis. We propose that environmental factors (pesticides and infections) increase the risk for iPD via the immune system and that the role of PD risk genes in immune cells is worthy of investigation. This review highlights the major PD-relevant genes expressed in immune cells and key environmental factors that activate immune cells and, alone or in combination with other factors, may contribute to iPD pathogenesis. By reviewing these interactions, we seek to enable the future development of immunomodulatory approaches to prevent or delay onset of iPD. © 2020 International Parkinson and Movement Disorder Society.

The immunology of rheumatoid arthritis

The immunopathogenesis of rheumatoid arthritis (RA) spans decades, beginning with the production of autoantibodies against post-translationally modified proteins (checkpoint 1). After years of asymptomatic autoimmunity and progressive immune system remodeling, tissue tolerance erodes and joint inflammation ensues as tissue-invasive effector T cells emerge and protective joint-resident macrophages fail (checkpoint 2). The transition of synovial stromal cells into autoaggressive effector cells converts synovitis from acute to chronic destructive (checkpoint 3). The loss of T cell tolerance derives from defective DNA repair, causing abnormal cell cycle dynamics, telomere fragility and instability of mitochondrial DNA. Mitochondrial and lysosomal anomalies culminate in the generation of short-lived tissue-invasive effector T cells. This differentiation defect builds on a metabolic platform that shunts glucose away from energy generation toward the cell building and motility programs. The next frontier in RA is the development of curative interventions, for example, reprogramming T cell defects during the period of asymptomatic autoimmunity.

The role of senescent T cells in immunopathology

The development of senescence in tissues of different organs and in the immune system are usually investigated independently of each other although during ageing, senescence in both cellular systems develop concurrently. Senescent T cells are highly inflammatory and secrete cytotoxic mediators and express natural killer cells receptors (NKR) that bypass their antigen specificity. Instead they recognize stress ligands that are induced by inflammation or infection of different cell types in tissues. In this article we discuss data on T cell senescence, how it is regulated and evidence for novel functional attributes of senescent T cells. We discuss an interactive loop between senescent T cells and senescent non-lymphoid cells and conclude that in situations of intense inflammation, senescent cells may damage healthy tissue. While the example for immunopathology induced by senescent cells that we highlight is cutaneous leishmaniasis, this situation of organ damage may apply to other infections, including COVID-19 and also rheumatoid arthritis, where ageing, inflammation and senescent cells are all part of the same equation.

Autoimmune hemolytic anemia: current knowledge and perspectives

Autoimmune hemolytic anemia (AIHA) is an acquired, heterogeneous group of diseases which includes warm AIHA, cold agglutinin disease (CAD), mixed AIHA, paroxysmal cold hemoglobinuria and atypical AIHA. Currently CAD is defined as a chronic, clonal lymphoproliferative disorder, while the presence of cold agglutinins underlying other diseases is known as cold agglutinin syndrome. AIHA is mediated by autoantibodies directed against red blood cells (RBCs) causing premature erythrocyte destruction. The pathogenesis of AIHA is complex and still not fully understood. Recent studies indicate the involvement of T and B cell dysregulation, reduced CD4+ and CD25+ Tregs, increased clonal expansions of CD8 + T cells, imbalance of Th17/Tregs and Tfh/Tfr, and impaired lymphocyte apoptosis. Changes in some RBC membrane structures, under the influence of mechanical stimuli or oxidative stress, may promote autohemolysis. The clinical presentation and treatment of AIHA are influenced by many factors, including the type of AIHA, degree of hemolysis, underlying diseases, presence of concomitant comorbidities, bone marrow compensatory abilities and the presence of fibrosis and dyserthropoiesis. The main treatment for AIHA is based on the inhibition of autoantibody production by mono- or combination therapy using GKS and/or rituximab and, rarely, immunosuppressive drugs or immunomodulators. Reduction of erythrocyte destruction via splenectomy is currently the third line of treatment for warm AIHA. Supportive treatment including vitamin supplementation, recombinant erythropoietin, thrombosis prophylaxis and the prevention and treatment of infections is essential. New groups of drugs that inhibit immune responses at various levels are being developed intensively, including inhibition of antibody-mediated RBCs phagocytosis, inhibition of B cell and plasma cell frequency and activity, inhibition of IgG recycling, immunomodulation of T lymphocytes function, and complement cascade inhibition. Recent studies have brought about changes in classification and progress in understanding the pathogenesis and treatment of AIHA, although there are still many issues to be resolved, particularly concerning the impact of age-associated changes to immunity.

Case of pemphigoid with immunoglobulin G antibodies to BP180 C-terminal domain and laminin-γ1 (p200) developed after pneumococcal vaccination

Pemphigoid cases have been reported in association with vaccination, including pneumococcal vaccination in infants but not in adults. There are also sporadic reports of pemphigoid diseases involving reactions to multiple autoantigens. We herein report a 75-year-old Japanese patient with pemphigoid who had immunoglobulin G antibodies to both the BP180 C-terminal domain and laminin-γ1 (p200), which developed 1 day after pneumococcal vaccination.

Conventional Treatment for Multiple Myeloma Drives Premature Aging Phenotypes and Metabolic Dysfunction in T Cells

New diagnoses of multiple myeloma (MM) tend to occur after the age of 60, by which time thymic output is severely reduced. As a consequence, lymphocyte recovery after lymphopenia-inducing anti-MM therapies relies on homeostatic proliferation of peripheral T cells rather than replenishment by new thymic emigrants. To assess lymphocyte recovery and phenotype in patients with newly diagnosed MM (NDMM) and relapsed/refractory MM (RRMM), we tracked CD4+ and CD8+ T cell populations at serial time points throughout treatment and compared them to age-matched healthy donors (HD). Anti-MM therapies and autologous stem cell transplant (ASCT) caused a permanent reduction in the CD4:8 ratio, a decrease in naïve CD4+ T cells, and an increase in effector memory T cells and PD1-expressing CD4+ T cells. Transcriptional profiling highlighted that genes associated with fatty acid β-oxidation were upregulated in T cells in RRMM, suggesting increased reliance on mitochondrial respiration. High mitochondrial mass was seen in all T cell subsets in RRMM but with relatively suppressed reactive oxygen species and mitochondrial membrane potential, indicating mitochondrial dysfunction. These findings highlight that anti-MM and ASCT therapies perturb the composition of the T cell compartment and drive substantial metabolic remodeling, which may affect the fitness of T cells for immunotherapies. This is particularly pertinent to chimeric antigen receptor (CAR)-T therapy, which might be more efficacious if T cells were stored prior to ASCT rather than at relapse.

Premature aging of circulating T cells predicts all-cause mortality in hemodialysis patients

Background

Patients with end-stage renal disease (ESRD) exhibit a premature aging phenotype of immune system, which is recently concerned as a significant factor for increased risk of various morbidities. Nevertheless, there are few dates explicating the relevancy of T cell senescence to mortality. In this study, we prospectively studied the predictive value of T cell senescence for mortality in hemodialysis patients.

Methods

Patients who had been on hemodialysis treatment for at least 6 months were enrolled. T cell senescence determined by differentiation status was evaluated by flow cytometry. Survival outcomes were estimated using the Kaplan-Meier method. Univariate and multivariate analyses were performed to evaluate the prognostic impact of T cell premature aging and other clinical factors on all-cause mortality.

Results

A total of 466 patients (277 man and 169 women) were enrolled in this study. Decreased number of naïve T cell, as the most prominent feature of T cell senescence, did not change in parallel with age in these patients. Decreased absolute count of T cell, naïve T cell, CD4⁺ naïve T cell were independently associated with all-cause mortality. Decreased percentage of T cell and increased percentage of CD8⁺central-memory T cell were also independently associated with all-cause mortality. After including all the T cell parameters in one regression model, only decreased count of naïve T cell was significantly associated with increased mortality in these patients.

Conclusions

Aging-associated T cell changes are aggravated in ESRD patients. For the first time, our study demonstrates that naïve T cell depletion is a strong predictor of all-cause mortality in HD patients.

Alternatives to amyloid for Alzheimer's disease therapies-a symposium report

For decades, Alzheimer's disease research has focused on amyloid as the primary pathogenic agent. This focus has driven the development of numerous amyloid-targeting therapies; however, with one possible exception, none of these therapies have been effective in preventing or delaying cognitive decline in patients, and there are no approved disease-modifying agents. It is becoming more apparent that alternative drug targets are needed to address this complex disease. An increased understanding of Alzheimer's disease pathology has highlighted the need to target the appropriate disease pathology at the appropriate time in the disease course. Preclinical and early clinical studies have focused on targets, including inflammation, tau, vascular health, and the microbiome. This report summarizes the presentations from a New York Academy of Sciences' one-day symposium entitled "Alzheimer's Disease Therapeutics: Alternatives to Amyloid," held on November 20, 2019.

The p53 effector Perp mediates the persistence of CD4+ effector memory T-cell undergoing lymphopenia-induced proliferation

Under lymphopenic conditions, the rapid spontaneous proliferation produces cells that robustly differentiate into effector memory T (T_EM) cells, and the aberrant expansion is preferentially driven by self-antigens. The pool size of effector memory T-cell is governed by a complex homeostatic balance between proliferation and death. Perp is a critical effector involved in the p53-dependent apoptotic pathway and widely expressed in mammalian tissues. We have previously shown that Perp has a prominent role in activation-induced cell death of peripheral Th17 cells. Here, we show that Peripheral Perp^-/-CD4⁺ T_EM cells outcompete wild type T_EM cells for access to splenic niches in vivo. The skewing of the Perp^-/- T_EM cells compartment was not the result of a difference in lymphopenia-induced proliferation, but the resistance to apoptosis, particularly after anti-Fas treatment. Data presented in this work indicate that Perp mediates the persistence of CD4⁺ T_EM cells in irradiation-induced lymphopenic settings.

High Levels of Epstein-Barr Virus Nuclear Antigen-1-Specific Antibodies and Infectious Mononucleosis Act Both Independently and Synergistically to Increase Multiple Sclerosis Risk

Objective: Elevated levels of anti-EBNA-1 antibodies and infectious mononucleosis (IM) history have consistently been associated with multiple sclerosis (MS) risk. We aimed to study whether these aspects of Epstein–Barr virus (EBV) infection represent separate risk factors for MS and whether they both interact with MS-associated HLA genes in disease development.

Methods: Two Swedish-population-based case–control studies were used, comprising 5,316 cases and 5,431 matched controls. Subjects with different HLA alleles, EBNA-1, and IM status were compared regarding MS risk by calculating odds ratios (OR) with 95% confidence intervals (CI) employing logistic regression. Causal mediation analysis was used to assess to what extent the relationship between IM history and MS risk was mediated by high anti-EBNA-1 antibody levels and vice versa.

Results: The causal mediation analysis revealed that both aspects of EBV infection mainly act directly on MS risk. The direct effect of elevated anti-EBNA-1 antibody levels on MS risk, expressed on the OR scale, was 2.8 (95% CI 2.5–3.1), and the direct effect of IM history on MS risk was 1.7 (95% CI 1.5–2.0). A significant interaction between the two aspects of EBV infection was observed (RERI 1.2, 95% CI 0.3–2.0), accounting for about 50% of the total effect. Further, both aspects of EBV infection interacted with DRB1^*15:01 and absence of A^*02:01.

Interpretation: Elevated anti-EBNA-1 antibody levels and IM history are different risk factors for MS. The two aspects of EBV infection act synergistically to increase MS risk, indicating that they partly are involved in the same biological pathways.

T cells, natural killer cells, and γδT cells in a large patient cohort with rheumatoid arthritis: influence of age and anti-rheumatic therapy

Objective: The aim of this cohort study was to evaluate the distribution of natural killer (NK) cells and T-cell subsets, including γδT cells, in the peripheral blood of patients with rheumatoid arthritis (RA) in a large real-life patient cohort, taking into account the patients' demographics, disease characteristics, and anti-rheumatic therapy.Method: The study recruited 508 RA patients between November 2013 and August 2015. Lymphocyte differentiation using eight-colour flow cytometry (fluorescence-activated cell sorting) of the peripheral blood was performed for all patients. Clinical data, including age, gender, disease duration, serostatus, disease activity, antibody status, immunosuppressive therapy including use of different biological disease-modifying anti-rheumatic drugs (bDMARDs) and conventional synthetic DMARDs, were retrospectively assessed using electronic patient files. Multivariate regression analysis was performed to assess the effect of these variables on T-cell, NK-cell, and γδT-cell counts.Results: The median patient age was 61.0 years and 74.1% were female. The median disease duration of RA was 12.0 years. Median Disease Activity Score based on 28-joint count was 2.8 and 56.3% were treated with bDMARDs. There were no differences in immunosuppressive therapy between different age groups. While rituximab, abatacept, and tocilizumab had no influence on lymphocyte subdifferentiation, tumour necrosis factor (TNF) inhibitors and age significantly influenced the numbers of T cells, T-helper cells, T-NK cells, NK cells, and γδT cells.Conclusion: Age and TNF-inhibition therapy influence lymphocyte subdifferentiation in patients with RA. It may be prudent to use age- and therapy-adjusted standard values for lymphocyte subsets during clinical trials and treatment of RA.

Immunology of the ageing kidney

Immunosenescence involves a series of ageing-induced alterations in the immune system and is characterized by two opposing hallmarks: defective immune responses and increased systemic inflammation. The immune system is modulated by intrinsic and extrinsic factors and undergoes profound changes in response to the ageing process. Immune responses are therefore highly age-dependent. Emerging data show that immunosenescence underlies common mechanisms responsible for several age-related diseases and is a plastic state that can be modified and accelerated by non-heritable environmental factors and pharmacological intervention. In the kidney, resident macrophages and fibroblasts are continuously exposed to components of the external environment, and the effects of cellular reprogramming induced by local immune responses, which accumulate with age, might have a role in the increased susceptibility to kidney disease among elderly individuals. Additionally, because chronic kidney disease, especially end-stage renal disease, is often accompanied by immunosenescence, which affects these patients independently of age, and many kidney diseases are strongly age-associated, treatment approaches that target immunosenescence might be particularly clinically relevant.

Immunotherapeutics in Multiple Myeloma: How Can Translational Mouse Models Help?

Multiple myeloma (MM) is usually diagnosed in older adults at the time of immunosenescence, a collection of age-related changes in the immune system that contribute to increased susceptibility to infection and cancer. The MM tumor microenvironment and cumulative chemotherapies also add to defects in immunity over the course of disease. In this review we discuss how mouse models have furthered our understanding of the immune defects caused by MM and enabled immunotherapeutics to progress to clinical trials, but also question the validity of using immunodeficient models for these purposes. Immunocompetent models, in particular the 5T series and Vk^⁎MYC models, are increasingly being utilized in preclinical studies and are adding to our knowledge of not only the adaptive immune system but also how the innate system might be enhanced in anti-MM activity. Finally we discuss the concept of immune profiling to target patients who might benefit the most from immunotherapeutics, and the use of humanized mice and 3D culture systems for personalized medicine.

Aging, Immunity, and Neuroinflammation: The Modulatory Potential of Nutrition

Aging influences an organism’s entire physiology, affecting functions at the molecular, cellular, and systemic levels and increasing susceptibility to many major chronic diseases. The changes in the immune system that accompany human aging are very complex and are generally referred to as immunosenescence. The factors and mechanisms of immunosenescence are multiple and include, among others, defects in the bone marrow, thymic involution, and intrinsic defects in the formation, maturation, homeostasis, and migration of peripheral lymphocytes. Aging affects both the innate and adaptive arms of the immune system. The process of aging is commonly accompanied by low-grade inflammation thought to contribute to neuroinflammation and to many age-related diseases. Numerous attempts to define the role of chronic inflammation in aging have implicated chronic oxidative stress, mitochondrial damage, immunosenescence, epigenetic modifications, and other phenomena. Several lifestyle strategies, such as intervening to provide an adequate diet and physical and mental activity, have been shown to result in improved immune and neuroprotective functions, a decrease in oxidative stress and inflammation, and a potential increase in individual longevity. The studies published thus far describe a critical role for nutrition in maintaining the immune response of the aged, but they also indicate the need for a more in-depth, holistic approach to determining the optimal nutritional and behavioral strategies that would maintain immune and other physiological systems in elderly people. In this chapter, we focus first on the age-related changes of the immune system. Further, we discuss possible deleterious influences of immunosenescence and low-grade inflammation (inflammaging) on neurodegenerative processes in the normally aging brain. Finally, we consider our current understanding of the modulatory potential of nutrition that may mediate anti-inflammatory effects and thus positively affect immunity and the aging brain.

CXCR3high CD8+ T cells with naïve phenotype and high capacity for IFN-γ production are generated during homeostatic T-cell proliferation

Naïve phenotype (NP) T cells spontaneously initiate homeostatic proliferation (HP) as T-cell output is reduced because of physiologic thymic involution with age. However, the effects of sustained HP on overall immune function are poorly understood. We demonstrated that the NP CD8⁺ T cell population in adult thymectomized mice showing accelerated HP has an increased capacity for TCR-mediated interferon-γ and tumor necrosis factor α production, which is attributed to an increase in CXCR3⁺ cells in the NP CD8⁺ T cell population. The CXCR3⁺ NP CD8⁺ T cells developed during persistent HP with a slow cell division rate, but rarely during robust antigen-driven proliferation with a fast cell division rate. In ontogeny, the proportions of CXCR3⁺ cells in the NP CD8⁺ T cell population showed a biphasic profile, which was high at the newborn and aged stages. Upon transfer, CXCR3⁺ NP CD8⁺ T cells, but not CXCR3^- NP CD8⁺ T cells, potently enhanced Th17-mediated inflammatory tissue reactions in vivo. Furthermore, CXCR3^high NP CD8⁺ T cells with similar features were also detected at variable levels in healthy human blood. These results suggest that CXCR3⁺ NP CD8⁺ T cells generated during physiological HP significantly impact overall immunity at the immunologically vulnerable neonatal and aged stages.