Tag: T-cells

Hypocortisolemic ASIA: a vaccine- and chronic infection-induced syndrome behind the origin of long COVID and myalgic encephalomyelitis

Abstract:

Myalgic encephalomyelitis or chronic fatigue syndrome (ME/CFS), long COVID (LC) and post-COVID-19 vaccine syndrome show similarities in their pathophysiology and clinical manifestations. These disorders are related to viral or adjuvant persistence, immunological alterations, autoimmune diseases and hormonal imbalances.

A developmental model is postulated that involves the interaction between immune hyperactivation, autoimmune hypophysitis or pituitary hypophysitis, and immune depletion. This process might begin with a deficient CD4 T-cell response to viral infections in genetically predisposed individuals (HLA-DRB1), followed by an uncontrolled immune response with CD8 T-cell hyperactivation and elevated antibody production, some of which may be directed against autoantigens, which can trigger autoimmune hypophysitis or direct damage to the pituitary, resulting in decreased production of pituitary hormones, such as ACTH. As the disease progresses, prolonged exposure to viral antigens can lead to exhaustion of the immune system, exacerbating symptoms and pathology.

It is suggested that these disorders could be included in the autoimmune/adjuvant-induced inflammatory syndrome (ASIA) because of their similar clinical manifestations and possible relationship to genetic factors, such as polymorphisms in the HLA-DRB1 gene. In addition, it is proposed that treatment with antivirals, corticosteroids/ginseng, antioxidants, and metabolic precursors could improve symptoms by modulating the immune response, pituitary function, inflammation and oxidative stress.

Therefore, the purpose of this review is to suggest a possible autoimmune origin against the adenohypophysis and a possible improvement of symptoms after treatment with corticosteroid replacement therapy.

Source: Manuel Ruiz-Pablos, Bruno Paiva, Aintzane Zabaleta. Hypocortisolemic ASIA: a vaccine- and chronic infection-induced syndrome behind the origin of long COVID and myalgic encephalomyelitis. Front. Immunol., 08 July 2024, Sec. Viral Immunology, Volume 15 – 2024 | https://doi.org/10.3389/fimmu.2024.1422940 https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2024.1422940/full (Full text)

Oxidative Stress is a shared characteristic of ME/CFS and Long COVID

Abstract:

More than 65 million individuals worldwide are estimated to have Long COVID (LC), a complex multisystemic condition, wherein patients of all ages report fatigue, post-exertional malaise, and other symptoms resembling myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). With no current treatments or reliable diagnostic markers, there is an urgent need to define the molecular underpinnings of these conditions.

By studying bioenergetic characteristics of peripheral blood lymphocytes in over 16 healthy controls, 15 ME/CFS, and 15 LC, we find both ME/CFS and LC donors exhibit signs of elevated oxidative stress, relative to healthy controls, especially in the memory subset. Using a combination of flow cytometry, bulk RNA-seq analysis, mass spectrometry, and systems chemistry analysis, we also observed aberrations in ROS clearance pathways including elevated glutathione levels, decreases in mitochondrial superoxide dismutase levels, and glutathione peroxidase 4 mediated lipid oxidative damage.

Critically, these changes in redox pathways show striking sex-specific trends. While females diagnosed with ME/CFS exhibit higher total ROS and mitochondrial calcium levels, males with an ME/CFS diagnosis have normal ROS levels, but larger changes in lipid oxidative damage. Further analyses show that higher ROS levels correlates with hyperproliferation of T cells in females, consistent with the known role of elevated ROS levels in the initiation of proliferation. This hyperproliferation of T cells can be attenuated by metformin, suggesting this FDA-approved drug as a possible treatment, as also suggested by a recent clinical study of LC patients.

Thus, we report that both ME/CFS and LC are mechanistically related and could be diagnosed with quantitative blood cell measurements. We also suggest that effective, patient tailored drugs might be discovered using standard lymphocyte stimulation assays.

Source: Vishnu Shankar, Julie Wilhelmy, Basil Michael, Layla Cervantes, Vamsee Mallajosyula, Ronald Davis, Michael Snyder, Shady Younis,
William H Robinson, Sadasivan Shankar, Paul Mischel, Hector Bonilla, Mark Davis. Oxidative Stress is a shared characteristic of ME/CFS and Long COVID. bioRxiv 2024.05.04.592477; doi: https://doi.org/10.1101/2024.05.04.592477  https://www.biorxiv.org/content/10.1101/2024.05.04.592477v1https://www.biorxiv.org/content/10.1101/2024.05.04.592477v1 (Full text available as PDF file)

Pituitary–Adrenal Axis and Peripheral Immune Cell Profile in Long COVID

Abstract:

In Long COVID, dysfunction in the pituitary–adrenal axis and alterations in immune cells and inflammatory status are warned against. We performed a prospective study in a cohort of 42 patients who suffered COVID-19 at least 6 months before attending the Long COVID unit at Althaia Hospital.
Based on Post-COVID Functional Status, 29 patients were diagnosed with Long COVID, while 13 were deemed as recovered. The hormones of the pituitary–adrenal axis, adrenocorticotropin stimulation test, and immune cell profiles and inflammatory markers were examined. Patients with Long COVID had significantly lower EuroQol and higher mMRC scores compared to the recovered individuals. Their symptoms included fatigue, myalgia, arthralgia, persistent coughing, a persistent sore throat, dyspnoea, a lack of concentration, and anxiety.
We observed the physiological levels of cortisol and adrenocorticotropin in individuals with or without Long COVID. The results of the adrenocorticotropin stimulation test were similar between both groups. The absolute number of neutrophils was lower in the Long COVID patients compared to recovered individuals (p < 0.05). The total count of B lymphocytes remained consistent, but Long COVID patients had a higher percentage of mature B cells compared to recovered participants (p < 0.05) and exhibited a higher percentage of circulating resident memory CD8+ T cells (p < 0.05) and Treg-expressing exonucleases (p < 0.05).
Our findings did not identify adrenal dysfunction related to Long COVID, nor an association between adrenal function and clinical symptoms. The data indicated a dysregulation in certain immune cells, pointing to immune activation. No overt hyperinflammation was observed in the Long COVID group.
Source: Alijotas-Reig J, Anunciacion-Llunell A, Esteve-Valverde E, Morales-Pérez S, Rivero-Santana S, Trapé J, González-García L, Ruiz D, Marques-Soares J, Miro-Mur F. Pituitary–Adrenal Axis and Peripheral Immune Cell Profile in Long COVID. Biomedicines. 2024; 12(3):581. https://doi.org/10.3390/biomedicines12030581 https://www.mdpi.com/2227-9059/12/3/581 (Full text)

Spontaneous, persistent, T cell-dependent IFN-γ release in patients who progress to Long Covid

Abstract:

After acute infection with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), a proportion of patients experience persistent symptoms beyond 12 weeks, termed Long Covid. Understanding the mechanisms that cause this debilitating disease and identifying biomarkers for diagnostic, therapeutic, and monitoring purposes are urgently required.

We detected persistently high levels of interferon-γ (IFN-γ) from peripheral blood mononuclear cells of patients with Long Covid using highly sensitive FluoroSpot assays. This IFN-γ release was seen in the absence of ex vivo peptide stimulation and remains persistently elevated in patients with Long Covid, unlike the resolution seen in patients recovering from acute SARS-CoV-2 infection. The IFN-γ release was CD8+ T cell-mediated and dependent on antigen presentation by CD14+ cells.

Longitudinal follow-up of our study cohort showed that symptom improvement and resolution correlated with a decrease in IFN-γ production to baseline levels. Our study highlights a potential mechanism underlying Long Covid, enabling the search for biomarkers and therapeutics in patients with Long Covid.

Source: Krishna BA, Lim EY, Metaxaki M, Jackson S, Mactavous L; NIHR BioResource; Lyons PA, Doffinger R, Bradley JR, Smith KGC, Sinclair J, Matheson NJ, Lehner PJ, Sithole N, Wills MR. Spontaneous, persistent, T cell-dependent IFN-γ release in patients who progress to Long Covid. Sci Adv. 2024 Feb 23;10(8):eadi9379. doi: 10.1126/sciadv.adi9379. Epub 2024 Feb 21. PMID: 38381822; PMCID: PMC10881041. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10881041/ (Full text)

Restrained memory CD8+ T cell responses favors viral persistence and elevated IgG responses in patients with severe Long COVID

Abstract:

During the COVID-19 pandemic it was widely described that certain individuals infected by SARS-CoV-2 experience persistent disease signs and symptoms, Long COVID, which in some cases is very severe with life changing consequences. To maximize our chances of identifying the underpinnings of this illness, we have focused on 121 of the most severe cases from >1000 patients screened in specialized clinics in Sweden and Belgium. We restricted this study to subjects with objective measures of organ damage or dysfunction, >3 months following a verified, but mild-to-moderate SARS-CoV-2 infection.

By performing systems-level immunological testing and comparisons to controls fully convalescent following a similar mild/moderate COVID-19 episode, we identify elevated serological responses to SARS-CoV-2 in severe Long COVID suggestive of chronic antigen stimulation. Persistent viral reservoirs have been proposed in Long COVID and using multiple orthogonal methods for detection of SARS-CoV-2 RNA and protein in plasma we identify a subset of patients with detectable antigens, but with minimal overlap across assays, and no correlation to symptoms or immune measurements.

Elevated serologic responses to SARS-CoV-2 on the other hand were inversely correlated with clonally expanded memory CD8+ T cells, indicating that restrained clonal expansion enables viral persistence, chronic antigen exposure and elevated IgG responses, even if antigen-detection in blood is not universally possible.

Source: Lucie Rodriguez, Ziyang Tan, Tadepally Lakshmikanth, Jun Wang, Hugo Barcenilla, Zoe Swank, Fanglei Zuo, Hassan Abolhassani, Ana Jimena Pavlovitch-Bedzyk, Chunlin Wang, Laura Gonzalez, Constantin Habimana Mugabo, Anette Johnsson, Yang Chen, Anna James, Jaromir Mikes, Linn Kleberg, Christopher Sundling, Mikael Björnson, Malin Nygren Bonnier, Marcus Ståhlberg, Michael Runold, Sophia Björkander, Erik Melén, Isabelle Meyts, Johan Van Weyenbergh, Qian-Pan Hammarström, Mark M Davis, David R. Walt, Nils Landegren, COVID Human Genetic Effort, Alessandro Aiuti, Giorgio Casari, Jean-Laurent Casanova, Marc Jamoulle, Judith Bruchfeld, Petter Brodin. Restrained memory CD8+ T cell responses favors viral persistence and elevated IgG responses in patients with severe Long COVID. medRxiv 2024.02.11.24302636; doi: https://doi.org/10.1101/2024.02.11.24302636 https://www.medrxiv.org/content/10.1101/2024.02.11.24302636v1.full-text (Full text)

Immune cell exhaustion, dysfunction, and metabolism in myalgic encephalomyelitis/chronic fatigue syndrome

Abstract;
Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a chronic and incapacitating multisystem condition with unknown etiology, no cure, and no FDA- approved treatments, all of which can be attributed to historical underfunding, widespread misinformation, and the complexity of the disease. Many patients encounter several immune-related symptoms, extreme fatigue, post-exertional malaise, and a flu-like onset. Studies have documented changes in ME/CFS immune cell populations and decreased natural killer (NK) cell performance, along with aberrant cytokine production, reduced glycolysis in T cells, and altered metabolites relevant to fatty acid oxidation, implicating potential intracellular metabolic dysregulation.
This knowledge prompted me to investigate fatty acid oxidation and immune cell functional states in isolated ME/CFS lymphocytes. Using extracellular flux analysis and flow cytometry, I observed elevated fatty acid oxidation levels in ME/CFS immune cells, including NK cells, CD4+ memory cells, CD4+ effector cells, CD8+ naïve cells, and CD8+ memory cells compared to healthy controls, particularly during high energy demands and activation. My findings suggest a metabolic dysfunction in ME/CFS immune cells, consistent with T cell exhaustion – a state that hinders immune cell proliferation, survival, and cytokine production following persistent antigen stimulation.
Building upon these results, I further investigated immune cell exhaustion and dysfunction in isolated CD8+ and CD4+ T cells from ME/CFS and healthy samples. I analyzed T cell sub-populations, including naïve, effector, memory, regulatory, and helper T cells, for frequencies of inhibitory receptors and transcription factors associated with dysfunctional immune cell states.
I detected distinct transcription factor dynamics and elevated exhausted T cell phenotype proportions in ME/CFS CD8+ T cell populations compared to healthy controls. In ME/CFS CD4+ T cells, I also observed altered inhibitory receptor population frequencies compared to healthy control samples. Moreover, dysfunctional T cell features correlated with ME/CFS health status and symptom presentation.
Overall, my findings detect dysfunctional T cell states in specific ME/CFS cell populations, which can lead to reduced effector function that may contribute to ME/CFS symptom presentation. This work highlights the significance of assessing both metabolic components and immune cell dysfunction-associated targets in the development of potential therapeutic interventions for individuals with ME/CFS.
Source: Maya, Jessica. Immune cell exhaustion, dysfunction, and metabolism in myalgic encephalomyelitis/chronic fatigue syndrome. Cornell Theses and Dissertations. 2024. https://ecommons.cornell.edu/items/242f8723-6f87-47cc-b36d-bf51a21f4255

Identification of CD8 T-cell dysfunction associated with symptoms in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and Long COVID and treatment with a nebulized antioxidant/anti-pathogen agent in a retrospective case series

Highlights:

• Both Long COVID and ME/CFS are characterized by dysfunctional CD8 T-cells with severe deficiencies in their abilities to produce IFNγ and TNFα.

• In a small Long COVID and ME/CFS case series, patients’ immune deficiency and health improve during treatment period with a nebulized antioxidant, anti-pathogen and immune-modulatory pharmacological agent.

• This work provides evidence of a useful biomarker, CD8 T-cell dysfunction reminiscent of T cell exhaustion, that may assist diagnosis and have utility for tracking disease outcome during therapy, including response to a potential new treatment.

Abstract:

Background: Patients with post-acute sequelae of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection (PASC, i.e., Long COVID) have a symptom complex highly analogous to many features of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), suggesting they may share some aspects of pathogenesis in these similar disorders. ME/CFS is a complex disease affecting numerous organ systems and biological processes and is often preceded by an infection-like episode. It is postulated that the chronic manifestations of illness may result from an altered host response to infection or inability to resolve inflammation, as is being reported in Long COVID. The immunopathogenesis of both disorders is still poorly understood. Here, we show data that suggest Long COVID and ME/CFS may be due to an aberrant response to an immunological trigger-like infection, resulting in a dysregulated immune system with CD8 T-cell dysfunction reminiscent of some aspects of T-cell clonal exhaustion, a phenomenon associated with oxidative stress. As there is an urgent need for diagnostic tools and treatment strategies for these two related disabling disorders, here, in a retrospective case series, we have also identified a potential nebulized antioxidant/anti-pathogen treatment that has evidence of a good safety profile. This nebulized agent is comprised of five ingredients previously reported individually to relieve oxidative stress, attenuate NF-κB signaling, and/or to act directly to inhibit pathogens, including viruses. Administration of this treatment by nebulizer results in rapid access of small doses of well-studied antioxidants and agents with anti-pathogen potential to the lungs; components of this nebulized agent are also likely to be distributed systemically, with potential to enter the central nervous system.

Methods and Findings: We conducted an analysis of CD8 T-cell function and severity of symptoms by self-report questionnaires in ME/CFS, Long COVID and healthy controls. We developed a CD8 T-cell functional assay, assessing CD8 T-cell dysfunction by intracellular cytokine staining (ICS) in a group of ME/CFS (n = 12) and Long COVID patients (n = 8), comparing to healthy controls (HC) with similar age and sex (n = 10). Magnet-enriched fresh CD8 T-cells in both patient groups had a significantly diminished capacity to produce both cytokines, IFNγ or TNFα, after PMA stimulation when compared to HC. The symptom severity questionnaire showed similar symptom profiles for the two disorders. Fortuitously, through a retrospective case series, we were able to examine the ICS and questionnaire data of 4 ME/CFS and 4 Long COVID patients in conjunction with their treatment (3–15 months). In parallel with the treatment pursued electively by participants in this retrospective case series, there was an increase in CD8 T-cell IFNγ and TNFα production and a decrease in overall self-reported symptom severity score by 54%. No serious treatment-associated side effects or laboratory anomalies were noted in these patients.

Conclusions: Here, in this small study, we present two observations that appear potentially fundamental to the pathogenesis and treatment of Long COVID and ME/CFS. The first is that both disorders appear to be characterized by dysfunctional CD8 T-cells with severe deficiencies in their abilities to produce IFNγ and TNFα. The second is that in a small retrospective Long COVID and ME/CFS case series, this immune dysfunction and patient health improved in parallel with treatment with an immunomodulatory, antioxidant pharmacological treatment with anticipated anti-pathogen activity. This work provides evidence of the potential utility of a biomarker, CD8 T-cell dysfunction, and suggests the potential for benefit from a new nebulized antioxidant/anti-pathogen treatment. These immune biomarker data may help build capacity for improved diagnosis and tracking of treatment outcomes during clinical trials for both Long COVID and ME/CFS while providing clues to new treatment avenues that suggest potential efficacy for both conditions.

Source: Gil, A., Hoag, G.E., Salerno, J.P., Hornig, M., Klimas, N., Selin, L.K. Identification of CD8 T-cell dysfunction associated with symptoms in myalgic encephalomyelitis/ chronic fatigue syndrome (ME/CFS) and Long COVID and treatment with a nebulized antioxidant/antipathogen agent in a retrospective case series. Brain, Behavior, & Immunity – Health (2024), doi: https://doi.org/10.1016/j.bbih.2023.100720 https://www.sciencedirect.com/science/article/pii/S2666354623001345 (Full text)

Blood T cell phenotypes correlate with fatigue severity in post-acute sequelae of COVID-19

Abstract:

Purpose: Post-acute sequelae of COVID-19 (PASC) affect approximately 10% of convalescent patients. The spectrum of symptoms is broad and heterogeneous with fatigue being the most often reported sequela. Easily accessible blood biomarkers to determine PASC severity are lacking. Thus, our study aimed to correlate immune phenotypes with PASC across the severity spectrum of COVID-19.

Methods: A total of 176 originally immunonaïve, convalescent COVID-19 patients from a prospective cohort during the first pandemic phase were stratified by initial disease severity and underwent clinical, psychosocial, and immune phenotyping around 10 weeks after first COVID-19 symptoms. COVID-19-associated fatigue dynamics were assessed and related to clinical and immune phenotypes.

Results: Fatigue and severe fatigue were commonly reported irrespective of initial COVID-19 severity or organ-specific PASC. A clinically relevant increase in fatigue severity after COVID-19 was detected in all groups. Neutralizing antibody titers were higher in patients with severe acute disease, but no association was found between antibody titers and PASC. While absolute peripheral blood immune cell counts in originally immunonaïve PASC patients did not differ from unexposed controls, peripheral CD3+CD4+ T cell counts were independently correlated with fatigue severity across all strata in multivariable analysis.

Conclusions: Patients were at similar risk of self-reported PASC irrespective of initial disease severity. The independent correlation between fatigue severity and blood T cell phenotypes indicates a possible role of CD4+ T cells in the pathogenesis of post-COVID-19 fatigue, which might serve as a blood biomarker.

Source: Pink, I., Hennigs, J.K., Ruhl, L. et al. Blood T cell phenotypes correlate with fatigue severity in post-acute sequelae of COVID-19. Infection (2023). https://doi.org/10.1007/s15010-023-02114-8 https://link.springer.com/article/10.1007/s15010-023-02114-8 (Full text)

First-in-human immunoPET imaging of COVID-19 convalescent patients using dynamic total-body PET and a CD8-targeted minibody

Abstract:

With most of the T cells residing in the tissue, not the blood, developing noninvasive methods for in vivo quantification of their biodistribution and kinetics is important for studying their role in immune response and memory. This study presents the first use of dynamic positron emission tomography (PET) and kinetic modeling for in vivo measurement of CD8+ T cell biodistribution in humans. A 89Zr-labeled CD8-targeted minibody (89Zr-Df-Crefmirlimab) was used with total-body PET in healthy individuals (N = 3) and coronavirus disease 2019 (COVID-19) convalescent patients (N = 5).
Kinetic modeling results aligned with T cell–trafficking effects expected in lymphoid organs. Tissue-to-blood ratios from the first 7 hours of imaging were higher in bone marrow of COVID-19 convalescent patients compared to controls, with an increasing trend between 2 and 6 months after infection, consistent with modeled net influx rates and peripheral blood flow cytometry analysis. These results provide a promising platform for using dynamic PET to study the total-body immune response and memory.
Source: Omidvari N, Jones T, Price PM, Ferre AL, Lu J, Abdelhafez YG, Sen F, Cohen SH, Schmiedehausen K, Badawi RD, Shacklett BL, Wilson I, Cherry SR. First-in-human immunoPET imaging of COVID-19 convalescent patients using dynamic total-body PET and a CD8-targeted minibody. Sci Adv. 2023 Oct 13;9(41):eadh7968. doi: 10.1126/sciadv.adh7968. Epub 2023 Oct 12. PMID: 37824612; PMCID: PMC10569706. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10569706/ (Full text)

Comparative single-cell analysis reveals IFN-γ as a driver of respiratory sequelae post COVID-19

Abstract:

Post-acute sequelae of SARS-CoV-2 infection (PASC) represents an urgent public health challenge, with its impact resonating in over 60 million individuals globally. While a growing body of evidence suggests that dysregulated immune reactions may be linked with PASC symptoms, most investigations have primarily centered around blood studies, with few focusing on samples derived from post-COVID affected tissues. Further, clinical studies alone often provide correlative insights rather than causal relationships. Thus, it is essential to compare clinical samples with relevant animal models and conduct functional experiments to truly understand the etiology of PASC.

In this study, we have made comprehensive comparisons between bronchoalveolar lavage fluid (BAL) single-cell RNA sequencing (scRNAseq) data derived from clinical PASC samples and relevant PASC mouse models. This revealed a strong pro-fibrotic monocyte-derived macrophage response in respiratory PASC (R-PASC) in both humans and mice, and abnormal interactions between pulmonary macrophages and respiratory resident T cells.

IFN-g emerged as a key node mediating the immune anomalies in R-PASC. Strikingly, neutralizing IFN-g post the resolution of acute infection reduced lung inflammation, tissue fibrosis, and improved pulmonary gas-exchange function in two mouse models of R-PASC. Our study underscores the importance of performing comparative analysis to understand the root cause of PASC for developing effective therapies.

Source: Jie Sun, Chaofan Li, Wei Qian, Xiaoqin Wei. Comparative single-cell analysis reveals IFN-γ as a driver of respiratory sequelae post COVID-19. bioRxiv 2023.10.03.560739; doi: https://doi.org/10.1101/2023.10.03.560739 https://www.biorxiv.org/content/10.1101/2023.10.03.560739v1