The role of TEMRA cell-mediated immune senescence in the development and treatment of HIV disease

T cell immunophenotypes and IgE responses in patients with moderate-to-severe atopic dermatitis receiving dupilumab

BACKGROUND

Targeting the interleukin-4 receptor alpha (IL-4Rα) subunit has proven clinical efficacy in atopic dermatitis (AD).

OBJECTIVE

This study assessed the peripheral phenotype and function of T-cells, but also levels of total and sIgE and its receptors in AD patients receiving dupilumab.

METHODS

AD patients were clinically assessed (n = 75) and peripheral blood samples were taken (n = 25). Multiparametric flow cytometry was performed to characterize T-cell subsets (before treatment and 6 months later). Total and specific IgE were measured by ImmunoCap, soluble CD23 and FcεR1 in serum by ELISA, and eosinophils by differential blood analysis.

RESULTS

SCORing Atopic Dermatitis scores and body surface area involvement decreased upon treatment after 6 months of treatment to 67% and 77% from baseline. At the T cell level, we observed a 0.55-fold reduction of Th2-cells and a mean 27% increase in regulatory T-cells from baseline, accompanied by shifts towards Th1 and Th17 phenotypes. Furthermore, circulating CD4+CXCR5+TFH17 and CD4+CXCR5+TFH17.1 positive cells (mean 40% and 42%) and T-cell-specific IL-2 (+0.96-fold) and IL-10 (+1.96-fold) secretion increased, whereas IL-4 (mean -55%) and IL-17A (mean -27%) were reduced. Eosinophil counts (mean -22%), total IgE (mean -47%) and House Dust Mite sIgE (mean -40%) decreased, whereas CD23 and FcεR1 remained unchanged.

CONCLUSIONS

The T-cell and cytokine profiles during anti-IL4-Ra treatment suggest that targeting this pathway promotes a systemic shift of the T-cell compartment by reducing the T helper type 2 and complementary IgE responses. The sustainability of these disease-modifying effects requires further investigation.

Osteoarthritis increases the risk of inflammatory arthritis due to immune checkpoint inhibitors associated with tissue-resident memory T cells

OBJECTIVE

Immune checkpoint inhibitors (ICIs) have significantly advanced cancer treatment, but they can also lead to immune-related adverse events (irAEs), including inflammatory arthritis. Understanding the risk factors and underlying mechanisms of irAE pathogenesis is crucial for optimal patient management. Increasing evidence suggests that ICI-mediated activation of tissue-resident memory T cells (TRM) significantly eliminates cancer cells and is associated with irAE-related colitis and dermatitis. However, it remains unknown why the development of these irAEs is restricted to a subset of patients. We hypothesized that osteoarthritis (OA) associated tissue damage and chronic inflammation lead to the recruitment and differentiation of joint TRM cells, predisposing individuals to ICI-induced arthritis.

METHODS

Using a comprehensive approach, we compared the prevalence of OA in patients with irAE-arthritis to those with irAE non-arthritis and those without irAEs. Additionally, we used advanced immunophenotyping techniques to characterize T-cell populations in the blood and synovial fluid of patients with OA and irAE-arthritis.

RESULTS

Our findings revealed a significantly higher prevalence of OA in patients who developed irAE-arthritis than controls. Furthermore, the multivariable analysis identified OA, body mass index, and smoking as independent risk factors for the development of irAE-arthritis. TRM cells expressing programmed cell death protein-1 (PD-1) were the predominant synovial T cells in OA joints. These cells were directly targeted by ICIs, resulting in an inflammatory immune response and the transition from OA to irAE-arthritis.

CONCLUSION

This study, the first of its kind, identifies OA as a significant risk factor for irAEarthritis. It reveals a potential mechanism by which ICIs activate PD-1-positive TRM cells in OA joints, resulting in tissue inflammation and irAE-arthritis. This research could significantly enhance the management and treatment of patients with cancer receiving ICIs.

YG, Babar P, S. VD, Tripathy AS. Durability of Functional SARS-CoV-2-Specific Immunological Memory and T Cell Response up to 8-9 Months Postrecovery From COVID-19

Research on long-term follow-up in individuals who have recovered from coronavirus disease-19 (COVID-19) would yield insights regarding their immunity status and identify those who need booster vaccinations. This study evaluated the longevity of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-specific cellular and humoral memory responses, as well as T cell effector functionalities, at 1-2 months (n = 40), 8-9 months (n = 40), and 12 months/1 year (n = 27) following recovery from SARS-CoV-2 infection. CTL response by enzyme-linked immunospot (ELISPOT); levels of cytokine by Bio-Plex, natural killer (NK), CD4+ helper, and CD8+ cytotoxic T cell functionalities using flow cytometry; anti-SARS-CoV-2 IgG by ELISA; and levels of neutralizing antibodies (NAbs) by surrogate virus NAb assay were assessed. The levels of SARS-CoV-2-specific IgG and NAb at 1-2 and 8-9 months postrecovery were hand in hand and appeared declining. SARS-CoV-2-specific B, memory B and plasma cells, and T cells sustained up to 8-9 months. Increased expression of CD107a/IFN-γ by NK cells and cytotoxic T cells at 8-9 months could be indicative of SARS-CoV-2-specific effector functions. Recovered individuals with positive and negative IgG antibody status displayed T cell response up to 1 year and 8-9 months, respectively, emphasizing the durabilty of effector immunity up to 8-9 months regardless of IgG antibody status. Overall, the recovered individuals exhibited robust immunological memory, sustained T cell response with effector functionality against SARS-CoV-2 that persists for at least 8-9 months.

Distinct CD8+ T-cell types Associated with COVID-19 Severity in Unvaccinated HLA-A2+ Patients

Although emerging data have revealed the critical role of memory CD8+ T cells in preventing and controlling SARS-CoV-2 infection, virus-specific CD8+ T-cell responses against SARS-CoV-2 and its memory and innate-like subsets in unvaccinated COVID-19 patients with various disease manifestations in an HLA-restricted fashion remain to be understood. Here, we show the strong association of protective cellular immunity with mild COVID-19 and unique cell types against SARS-CoV-2 virus in an HLA-A2 restricted manner. ELISpot assays reveal that SARS-CoV-2-specific CD8+ T-cell responses in mild COVID-19 patients are significantly higher than in severe patients, whereas neutralizing antibody responses against SARS-CoV-2 virus significantly correlate with disease severity. Single-cell analyses of HLA-A2-restricted CD8+ T cells, which recognize highly conserved immunodominant SARS-CoV-2-specific epitopes, demonstrate divergent profiles in unvaccinated patients with mild versus severe disease. CD8+ T-cell types including cytotoxic KLRB1 + CD8αα cells with innate-like T-cell signatures, IFNG hi ID3 hi memory cells and IL7R + proliferative stem cell-like memory cells are preferentially observed in mild COVID-19, whereas distinct terminally-differentiated T-cell subsets are predominantly detected in severe COVID-19: highly activated FASL hi T-cell subsets and early-terminated or dysfunctional IL4R + GATA3 + stem cell-like memory T-cell subset. In conclusion, our findings suggest that unique and contrasting SARS-CoV-2-specific CD8+ T-cell profiles may dictate COVID-19 severity.

Infants display reduced NK cell responses in RSV and increased inflammatory responses in SARS-CoV-2 infections

Respiratory syncytial virus (RSV) is the leading cause of lower respiratory tract infection hospitalizations in infants and poses a significantly higher risk of respiratory failure than SARS-CoV-2. The mechanisms underlying these differences remain unclear. We analyzed blood samples from infants (median age 2.3 months) with SARS-CoV-2 (n = 30), RSV (n = 19), and healthy controls (n = 17) using single-cell transcriptomics and epigenomics, and cytokine profiling. Both viruses triggered comparable interferon responses across PBMC subsets but differed in NK cell and inflammatory responses. Severe RSV cases showed reduced NK cell frequencies, lower IFNG expression, and decreased chromatin accessibility at T-BET and EOMES binding sites. RSV infections were also associated with increased CD4+ TEMRA, memory Treg and transitional B cells. In contrast, SARS-CoV-2 was characterized by stronger pro-inflammatory signatures, including increased NFKB pathway activity and higher serum TNF concentrations. These findings highlight distinct immune responses to RSV and SARS-CoV-2, providing insights that may inform clinical decisions.

Deciphering long-term immune effects of HIV-1/SARS-CoV-2 co-infection: a longitudinal study

INTRODUCTION

While the general immune response to Severe Acute Respiratory Syndrome-Coronavirus-2 (SARS-CoV-2) is well-understood, the long-term effects of Human Immunodeficiency Virus-1/Severe Acute Respiratory Syndrome-Coronavirus-2 (HIV-1/SARS-CoV-2) co-infection on the immune system remain unclear. This study investigates the immune response in people with HIV-1 (PWH) co-infected with SARS-CoV-2 to understand its long-term health consequences.

METHODS

A retrospective longitudinal study of PWH with suppressed viral load and SARS-CoV-2 infection was conducted. Cryopreserved peripheral blood mononuclear cells and plasma samples were collected at three time-points: HIV-1/pre-SARS-CoV-2 (n = 18), HIV-1/SARS-CoV-2 (n = 46), and HIV-1/post-SARS-CoV-2 (n = 36). Plasma levels of 25 soluble cytokines and chemokines, and anti-S/anti-N-IgG-SARS-CoV-2 antibodies were measured. Immunophenotyping of innate and adaptive immune components and HIV-1 and SARS-CoV-2-specific T/B-cell responses were assessed by flow cytometry.

RESULTS

HIV-1/SARS-CoV-2 co-infection was associated with long-lasting immune dysfunction, characterized by elevated levels of pro-inflammatory cytokines and a decrease in the MIG-IP10-ITAC chemokine axis at the HIV/SARS-CoV-2 time-point, which persisted one year later. Additionally, alterations in the distribution of subsets and increased activation (NKG2D/NKG2C) and maturation (TIM3) markers of NK and dendritic cells were observed at the HIV-1/SARS-CoV-2 time-point, persisting throughout the study. Effector memory CD4 T-cell subsets were decreased, while exhaustion/senescence (PD1/TIM3/CD57) markers were elevated at all three time-points. SARS-CoV-2-specific T/B-cell responses remained stable throughout the study, while HIV-1-specific T-cell responses decreased at the HIV-1/SARS-CoV-2 time-point and remained so.

CONCLUSIONS

Persistent immune dysfunction in HIV-1/SARS-CoV-2 co-infection increases the risk of future complications, even in PWH with mild symptoms. Exacerbated inflammation and alterations in immune cells may contribute to reduce vaccine efficacy and potential reinfections.

Immune aging and infectious diseases

ABSTRACT

The rise in global life expectancy has led to an increase in the older population, presenting significant challenges in managing infectious diseases. Aging affects the innate and adaptive immune systems, resulting in chronic low-grade inflammation (inflammaging) and immune function decline (immunosenescence). These changes would impair defense mechanisms, increase susceptibility to infections and reduce vaccine efficacy in older adults. Cellular senescence exacerbates these issues by releasing pro-inflammatory factors, further perpetuating chronic inflammation. Moreover, comorbidities, such as cardiovascular disease and diabetes, which are common in older adults, amplify immune dysfunction, while immunosuppressive medications further complicate responses to infections. This review explores the molecular and cellular mechanisms driving inflammaging and immunosenescence, focusing on genomic instability, telomere attrition, and mitochondrial dysfunction. Additionally, we discussed how aging-associated immune alterations influence responses to bacterial, viral, and parasitic infections and evaluated emerging antiaging strategies, aimed at mitigating these effects to improve health outcomes in the aging population.

Triclocarban disrupts the activation and differentiation of human CD8+ T cells by suppressing the vitamin D receptor signaling

Triclocarban (TCC) is a widely applied environmental endocrine-disrupting chemical (EDC). Similar to most of EDCs, TCC potentially damages the immunity of various species. However, whether and how TCC impacts the adaptive immunity in mammals has yet to be determined. Herein, we discovered that TCC disrupts the activation and differentiation of CD8+ T cells in primary human peripheral blood samples, purified CD8+ T cells, and in mice in vivo. Mechanistically, TCC might block the activation of the vitamin D receptor (VDR) and reduce the synthesis of cholesterol, a precursor of vitamin D, resulting in inhibition of VDR signaling due to the suppression of both its ligand and the receptor itself by TCC. Our findings elucidate the hazard and potential mechanisms of TCC in mammalian adaptive immunity and highlighted VDR as a potential therapeutic target for the immunodeficiency caused by TCC.

Long COVID as a disease of accelerated biological aging: An opportunity to translate geroscience interventions

It has been four years since long COVID-the protracted consequences that survivors of COVID-19 face-was first described. Yet, this entity continues to devastate the quality of life of an increasing number of COVID-19 survivors without any approved therapy and a paucity of clinical trials addressing its biological root causes. Notably, many of the symptoms of long COVID are typically seen with advancing age. Leveraging this similarity, we posit that Geroscience-which aims to target the biological drivers of aging to prevent age-associated conditions as a group-could offer promising therapeutic avenues for long COVID. Bearing this in mind, this review presents a translational framework for studying long COVID as a state of effectively accelerated biological aging, identifying research gaps and offering recommendations for future preclinical and clinical studies.

The Impact of Immune System Aging on Infectious Diseases

Immune system aging is becoming a field of increasing public health interest because of prolonged life expectancy, which is not paralleled by an increase in health expectancy. As age progresses, innate and adaptive immune systems undergo changes, which are defined, respectively, as inflammaging and immune senescence. A wealth of available data demonstrates that these two conditions are closely linked, leading to a greater vulnerability of elderly subjects to viral, bacterial, and opportunistic infections as well as lower post-vaccination protection. To face this novel scenario, an in-depth assessment of the immune players involved in this changing epidemiology is demanded regarding the individual and concerted involvement of immune cells and mediators within endogenous and exogenous factors and co-morbidities. This review provides an overall updated description of the changes affecting the aging immune system, which may be of help in understanding the underlying mechanisms associated with the main age-associated infectious diseases.