Category: Immune System

Comparison of T-cell Receptor Diversity of people with Myalgic Encephalomyelitis versus controls

Abstract:

Objective: Myalgic Encephalomyelitis (ME; sometimes referred to as Chronic Fatigue Syndrome or CFS) is a chronic disease without laboratory test, detailed aetiological understanding or effective therapy. Its symptoms are diverse, but it is distinguished from other fatiguing illnesses by the experience of post-exertional malaise, the worsening of symptoms even after minor physical or mental exertion. Its frequent onset after infection might indicate that it is an autoimmune disease or that it arises from abnormal T-cell activation.

Results: To test this hypothesis, we sequenced the genomic loci of a/d, b and g T-cell receptors (TCR) from 40 human blood samples from each of four groups: severely affected people with ME/CFS; mildly or moderately affected people with ME/CFS; people diagnosed with Multiple Sclerosis, as disease controls; and, healthy controls. Seeking to automatically classify these individuals’ samples by their TCR repertoires, we applied P-SVM, a machine learning method. However, despite working well on a simulated data set, this approach did not partition samples into the four subgroups, beyond what was expected by chance alone.  Our findings do not support the hypothesis that blood samples from people with ME/CFS frequently contain altered T-cell receptor diversity.

Source: Joshua J Dibble, Ben Ferneyhough, Matthew Roddis et al. Comparison of T-cell Receptor Diversity of people with Myalgic Encephalomyelitis versus controls, 19 July 2023, PREPRINT (Version 1) available at Research Square [https://doi.org/10.21203/rs.3.rs-3164397/v1]  https://www.researchsquare.com/article/rs-3164397/v1 (Full text)

An understanding of the immune dysfunction in susceptible people who develop the post-viral fatigue syndromes Myalgic Encephalomyelitis/Chronic Fatigue Syndrome and Long COVID

Abstract:

Viral infection in most people results in a transient immune/inflammatory response resulting in elimination of the virus and recovery where the immune system returns to that of the pre-infectious state. In susceptible people by contrast there is a transition from an acute immune response to a chronic state that can lead to an ongoing lifelong complex post-viral illness, Myalgic Encephalomyelitis/Chronic Fatigue Syndrome. This susceptibility is proposed to be genetic or be primed by prior health history. Complex abnormalities occur in immune cell functions, immune cell metabolism and energy production, and in cytokine immune modulator regulation. The immune system of the brain/central nervous system becomes activated leading to dysfunction in regulation of body physiology and the onset of many neurological symptoms.

A dysfunctional immune system is core to the development of the post-viral condition as shown with diverse strategies of immune profiling.  Many studies have shown changes in numbers and activity of immune cells of different phenotypes and their metabolism. Immune regulating cytokines show complex altered patterns and vary with the stage of the disease, and there are elements of associated autoimmunity.  These complex changes are accompanied by an altered molecular homeostasis with immune cell transcripts and proteins no longer produced in a tightly regulated manner, reflected in the instability of the epigenetic code that controls gene expression.

Potential key elements of the altered immune function in this disease needing further exploration are changes to the gut-brain-immune axis as a result of changes in the microbiome of the gut, and viral reactivation from latent elements of the triggering virus or from a prior viral infection. Long COVID, an Myalgic Encephalomyelitis/Chronic Fatigue Syndrome-like illness, is the post-viral condition that has arisen in large numbers solely from the pandemic virus Severe Acute Respiratory Syndrome Coronovirus-2.

With over 760 million cases worldwide, an estimated ~100 million cases of Long COVID have occurred within a short period. This now provides an unprecedented opportunity to understand the progression of these post-viral diseases, and to progress from a research phase mainly documenting the immune changes to considering potential immunotherapies that might improve the overall symptom profile of affected patients, and provide them with a better quality of life.

Source: WALKER, Max O.M. et al. An understanding of the immune dysfunction in susceptible people who develop the post-viral fatigue syndromes Myalgic Encephalomyelitis/Chronic Fatigue Syndrome and Long COVID. Medical Research Archives, [S.l.], v. 11, n. 7.1, july 2023. ISSN 2375-1924. Available at: <https://esmed.org/MRA/mra/article/view/4083>. Date accessed: 15 july 2023. doi: https://doi.org/10.18103/mra.v11i7.1.4083. https://esmed.org/MRA/mra/article/view/4083/99193547075 (Full text as PDF file)

A Thesis on Immune Differences in Chronic Fatigue Syndrome, Fibromyalgia and Healthy Controls

Abstract:

Background: Chronic Fatigue Syndrome (CFS) and Fibromyalgia (FM) are debilitating disorders that significantly affect the daily lives of those suffering from them, as well as their loved ones. Both conditions have overlapping clinical features that resemble inflammatory disorders, and overlapping symptoms, such as depression, suggest central nervous system (CNS) involvement. The role of the immune system’s soluble messengers in the pathogenesis of CFS and FM has been under investigation, but so far the results are inconclusive. In addition, there is growing evidence that the kynurenine pathway is involved in the pathology of diseases related to the CNS, yet the role of each metabolite is not clear. The relationship between kynurenine metabolism and CFS and FM has not been extensively explored. Few studies have simultaneously examined the immunological status in both CFS and FM, making this thesis the first to comprehensively evaluate the potential distinct immunological differences between the two disorders.

Objective: The objective of this study was to compare the CFS and FM with healthy controls, regarding the levels of several soluble blood markers related to the immune system. The markers chosen were:

  • The inflammatory marker high-sensitive CRP (hsCRP)
  • The following cytokines and chemokines: Interferon (IFN)-γ, Interleukin (IL)-1β, IL1ra, IL-4, IL-6, IL-8, IL-10, IL-17, Interferon gamma-induced protein (IP)-10, Monocyte Chemoattractant Protein (MCP)-1, Transforming Growth Factor (TGF)-β1, TGF-β2, TGF-β3 and Tumour Necrosis Factor (TNF)-α
  • The metabolites and their ratios of the kynurenine pathway: Tryptophan (Try), kynurenine (Kyn), kynurenic acid (KA), 3-hydroxykykynurenine (HK), anthranilic acid (AA), xanthurenic acid (XA), 3-hydroxyanthranilic acid (HAA), quinolinic acid (QA) and picolinic acid (Pic).

Method: The population consisted of three groups: CFS patients (n = 49), FM patients (n = 58), and healthy controls (n = 54). All participants were females aged 18–60. Patients were recruited from a specialised university hospital clinic and controls were recruited by advertisement among the staff and students at the hospital and university.

Plasma levels of hsCRP were analysed at the hospital. The cytokines and chemokines IFN-γ, IL-1β, IL-1ra, xii IL-4, IL-6, IL-8, IL-10, IL-17, IP-10, MCP-1, TGF-β1, TGF-β2, TGF-β3, and TNF-α were analysed by multiplex. Kynurenine metabolites were analysed by LC-MS/MS.

Linear regression models of log-transformed data for hsCRP and the kynurenine metabolites were conducted for comparison of the three groups CFS, FM and controls. The Kruskal-Wallis test was used to analyse differences of cytokines between the three groups. Main findings were controlled for age, body mass index (BMI), and symptoms of anxiety and depression.

Results: hsCRP levels were significantly higher for both the CFS and FM groups compared to healthy controls when adjusting for age and BMI (p = .006). There was no difference between the two patient groups. Level of hsCRP was affected by BMI (p < .001) but not age.

MCP-1 was significantly increased in both patient groups compared to healthy controls (p < .001). IL-1β, Il-4, IL-6, TNF-α, TGF-β1, TGF-β2, TGF-β3 (all p < .001), IL-10 (p = .003) and IL17 (p = .002) all were significantly lower in the patient groups compared to healthy controls. IFN-γ was significantly lower in the FM group (p < .001). For IL-8, IP-10 and IL1ra there were no significant difference.

QA differed between CFS and FM patients (p = .036) and was related to higher levels of BMI (p = .002). The KA/QA ratio was lower for CFS patients compared to healthy controls (p = .016). The KA/HK ratio was lower for FM patients compared to healthy controls, and this lower ratio was associated with increased symptoms of pain (p = .002). The kynurenine aminotransferase II (KAT II) enzymatic activity given by XA/HK was lower for FM patients compared to healthy controls (p = .013). In addition, BMI was negatively associated with enhanced KAT II enzymatic activity (p = .039).

Symptoms of anxiety and depression were not associated with any of the immune markers studied.

Conclusion: In our material hsCRP and MCP-1 are increased in patients both with CFS and with FM, while several other cytokines are either similar or significantly lower in patients than controls. Our study also indicates associations between kynurenine metabolism and CFS and FM. Kynurenine also is associated with single symptoms such as fatigue and pain. Forthcoming studies indicating interactions and causative effects, or restoration of the inflammatory status, may place cytokines and kynurenine metabolites as a target for treatment as well as prevention of these conditions in the future.

Source: Groven, Nina. A Thesis on Immune Differences in Chronic Fatigue Syndrome, Fibromyalgia and Healthy Controls. PhD Thesis [Norwegian University of Science and Technology] https://ntnuopen.ntnu.no/ntnu-xmlui/handle/11250/3072207 (Full text available as PDF file)

Increased circulating fibronectin, depletion of natural IgM and heightened EBV, HSV-1 reactivation in ME/CFS and long COVID

Abstract:

Myalgic Encephalomyelitis/ Chronic Fatigue syndrome (ME/CFS) is a complex, debilitating, long-term illness without a diagnostic biomarker. ME/CFS patients share overlapping symptoms with long COVID patients, an observation which has strengthened the infectious origin hypothesis of ME/CFS. However, the exact sequence of events leading to disease development is largely unknown for both clinical conditions.

Here we show antibody response to herpesvirus dUTPases, particularly to that of Epstein-Barr virus (EBV) and HSV-1, increased circulating fibronectin (FN1) levels in serum and depletion of natural IgM against fibronectin ((n)IgM-FN1) are common factors for both severe ME/CFS and long COVID. We provide evidence for herpesvirus dUTPases-mediated alterations in host cell cytoskeleton, mitochondrial dysfunction and OXPHOS.

Our data show altered active immune complexes, immunoglobulin-mediated mitochondrial fragmentation as well as adaptive IgM production in ME/CFS patients. Our findings provide mechanistic insight into both ME/CFS and long COVID development. Finding of increased circulating FN1 and depletion of (n)IgM-FN1 as a biomarker for the severity of both ME/CFS and long COVID has an immediate implication in diagnostics and development of treatment modalities.

Source: Zheng Liu, Claudia Hollmann, Sharada Kalanidhi, Arnhild Grothey, Samuel Keating, Irene Mena-Palomo, Stephanie Lamer, Andreas Schlosser, Agnes Kaiping, Carsten Scheller, Franziska Sotzny, Anna Horn, Carolin Nuernberger, Vladimir Cejka, Boshra Afshar, Thomas Bahmer, Stefan Schreiber, Joerg Janne Vehreschild, Olga Milljukov, Christian Schaefer, Luzie Kretzler, Thomas Keil, Jens-Peter Reese, Felizitas A Eichner, Lena Schmidbauer, Peter U Heuschmann, Stefan Stoerk, Caroline Morbach, Gabriela Riemekasten, Niklas Beyersdorf, Carmen Scheibenbogen, Robert K Naviaux, Marshall Williams, Maria E Ariza, Bhupesh Kumar Prusty. Increased circulating fibronectin, depletion of natural IgM and heightened EBV, HSV-1 reactivation in ME/CFS and long COVID. medRxiv 2023.06.23.23291827; doi: https://doi.org/10.1101/2023.06.23.23291827 https://www.medrxiv.org/content/10.1101/2023.06.23.23291827v1 (Full text available as PDF file)

Post-COVID sequalae effect in chronic fatigue syndrome: SARS-CoV-2 triggers latent adenovirus in the oral mucosa

Abstract:

The post-viral fatigue syndromes long COVID and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) have multiple, potentially overlapping, pathological processes. These include persisting reservoirs of virus e.g. SARS-CoV-2 in long COVID patient’s tissues, immune dysregulation with or without reactivation of underlying pathogens, such as Epstein-Barr virus (EBV) and human herpesvirus 6 (HHV6), as we recently described in ME/CFS, and possibly yet unidentified viruses.

In the present study we tested saliva samples from two cohorts for IgG against human adenovirus (HAdV): patients with ME/CFS (n=84) and healthy controls (n=94), with either mild/asymptomatic SARS-CoV-2 infection or no infection. A significantly elevated anti-HAdV IgG response after SARS-CoV-2 infection was detected exclusively in the patient cohort. Longitudinal/time analysis, before and after COVID-19, in the very same individuals confirmed HAdV IgG elevation after. In plasma there was no HAdV IgG elevation.

We conclude that COVID-19 triggered reactivation of dormant HAdV in the oral mucosa of chronic fatigue patients indicating an exhausted dysfunctional antiviral immune response in ME/CFS, allowing reactivation of adenovirus upon stress encounter such as COVID-19.

Source: Ulf Hannestad, Eirini Apostolou, Per Sjogren, Björn Bragée, Olli Polo, Bo C. Bertilson and Anders Rosén. Post-COVID sequalae effect in chronic fatigue syndrome: SARS-CoV-2 triggers latent adenovirus in the oral mucosa. Front. Med. Sec. Infectious Diseases: Pathogenesis and Therapy, Volume 10 – 2023 | doi: 10.3389/fmed.2023.1208181 https://www.frontiersin.org/articles/10.3389/fmed.2023.1208181/abstract

Increasing serum soluble CD40 ligand (sCD40L) may be a biomarker of ME/CFS and chronic Long COVID progression

Abstract:

To date, no single blood lab test exists to diagnose or track ME/CFS or chronic Long COVID. Based on existing literature, this article brings together evidence that a molecule secreted by the immune system called sCD40L tends to become increasingly elevated in ME/CFS, Long COVID, and Multiple Sclerosis.

These studies, along with what’s known about the role of sCD40L in health and other diseases, suggest sCD40L may be useful to track over time in ME/CFS and Long COVID patients.

Source: Vijay Iyer. Increasing serum soluble CD40 ligand (sCD40L) may be a biomarker of ME/CFS and chronic Long COVID progression. Patient-Generated Hypotheses Journal | Issue 1, May 2023. https://patientresearchcovid19.com/storage/2023/05/Patient-Generated-Hypotheses-Issue-1-May-2023.pdf#page=42 (Full text)

Inflammation-induced pain and fatigue in fibromyalgia and ME/CFS and role of variant connective tissue

Abstract:

Background: Fibromyalgia and ME/CFS are multifaceted conditions with overlapping symptoms(1); the pathophysiological mechanisms are under debate. It remains unclear whether dysregulated inflammation, induced either by an exogenous stimulus (eg a virus or other stressor), or autoimmunity, is of prime importance [2].

Objectives: 1. To determine in a novel human model the effects of an in vivo inflammatory challenge in the induction of pain and fatigue in fibromyalgia and ME/CFS compared to controls. 2. Explore potential mediators and moderators involved.

Methods: Data were available for 48 patients with confirmed diagnoses of Fibromyalgia and/ or ME/CFS and 22 matched controls, who had undergone a placebo controlled inflammatory challenge (typhoid vaccination) as part of ISRCTN78820481. Participants underwent full research diagnostic evaluation including a hypermobility assessment. Subjective pain and fatigue were assessed after saline injection and typhoid vaccination (VAS). Linear regression models were used to explore predictors, with adjustment for potential confounders (age/gender) and baseline levels as appropriate.

Mediation analyses (looking for mechanistic effects) were conducted according to the method of Hayes (3) and mediation considered significant if bootstrapped confidence intervals of the estimated indirect effect did not cross zero. In these mediation analyses predictor variable was group membership (patient or control), outcome variable was change in 1) pain and 2) fatigue induced by challenge and mediators/moderators included change in IL-6 induced by inflammatory challenge and hypermobility features.

Results: Being a patient rather than control significantly predicted inflammation-induced fatigue (B=14.89 (95%CI 3.29-26.50), t=2.56, p=0.013) and pain (B=12.88 (95%CI 0.65-25.10), t=2.11, p=0.039) after adjusting for levels induced by placebo.

Induced pain was independently predicted by level of IL-6 induced by inflammatory challenge (B=23.44 (95%CI 5.15-41.72),t=2.57, p=0.013) as was induced fatigue (B=10.63 (95%CI 2.84-18.41), t=2.73, p=0.008) Mediated moderation analyses suggested the link to induced pain and fatigue through induced inflammation was associated with hypermobility features (Index of mediated moderation 11.02 (95%CI 1.45-22.73) and 6.20 (95%CI 0.07-13.64) respectively))

Conclusion: To our knowledge this is the first human study to evaluate directly the effect of an exogenous inflammatory challenge (typhoid vaccination) in a combined group of Fibromyalgia and ME/CFS patients. Il-6 was shown to be a critical mediator. This work strongly supports the hypothesis that inflammation is key to the pathophysiology of ME/CFS. We are evaluating associated CNS inflammation in the model, as well as other associations, such as autonomic dysfunction and hypermobility. Further understanding the mediators involved in the condition should in future open the way to testing targeted anti-inflammatory therapy.

Source: Eccles J, Amato M, Themelis K, et alOP0194 INFLAMMATION-INDUCED PAIN AND FATIGUE IN FIBROMYALGIA AND ME/CFS AND ROLE OF VARIANT CONNECTIVE TISSUEAnnals of the Rheumatic Diseases 2023;82:129. https://ard.bmj.com/content/82/Suppl_1/129.2 (Full text)

Investigating antibody reactivity to the intestinal microbiome in severe myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS)

Abstract:

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a multisystemic disease of unknown aetiology that is characterised by disabling chronic fatigue and involves both the immune and gastrointestinal (GI) systems. Patients display alterations in GI microbiome with a significant proportion experiencing GI discomfort and pain and elevated blood biomarkers for altered intestinal permeability compared with healthy individuals.

To investigate a possible GI origin of ME/CFS we designed a feasibility study to test the hypothesis that ME/CFS pathogenesis is a consequence of increased intestinal permeability that results in microbial translocation and a breakdown in immune tolerance leading to generation of antibodies reactive to indigenous intestinal microbes. Secretory IgA and serum IgG levels and reactivity to intestinal microbes were assessed in five pairs of severe ME/CFS patients and matched same-household healthy controls. For profiling serum IgG we developed IgG-Seq which combines flow-cytometry based bacterial cell sorting and metagenomics to detect mucosal IgG reactivity to the microbiome.

We uncovered evidence for immune dysfunction in severe ME/CFS patients that was characterised by reduced capacity and reactivity of serum IgG to stool microbes, irrespective of their source. This study provides the rationale for additional studies in larger cohorts of ME/CFS patients to further explore immune-microbiome interactions.

Source: Katharine A. Seton, Marianne Defernez, Andrea Telatin, Sumeet K. Tiwari, George M. Savva, Antonietta Hayhoe, Alistair Noble, Ana Carvalho, Steve James, Amolak Bansal, Thomas Wileman, Simon R. Carding. Investigating antibody reactivity to the intestinal microbiome in severe myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). medRxiv 2023.05.21.23290299; doi: https://doi.org/10.1101/2023.05.21.23290299 https://www.medrxiv.org/content/10.1101/2023.05.21.23290299v1.full-text (Full text)

Free-water-corrected diffusion and adrenergic/muscarinic antibodies in myalgic encephalomyelitis/chronic fatigue syndrome

Abstract:

Background and purpose: Free-water-corrected diffusion tensor imaging (FW-DTI), a new analysis method for diffusion MRI, can indicate neuroinflammation and degeneration. There is increasing evidence of autoimmune etiology in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). We used FW-DTI and conventional DTI to investigate microstructural brain changes related to autoantibody titers in patients with ME/CFS.

Methods: We prospectively examined 58 consecutive right-handed ME/CFS patients who underwent both brain MRI including FW-DTI and a blood analysis of autoantibody titers against β1 adrenergic receptor (β1 AdR-Ab), β2 AdR-Ab, M3 acetylcholine receptor (M3 AchR-Ab), and M4 AchR-Ab. We investigated the correlations between these four autoantibody titers and three FW-DTI indices-free water (FW), FW-corrected fractional anisotropy (FAt), and FW-corrected mean diffusivity-as well as two conventional DTI indices-fractional anisotropy (FA) and mean diffusivity. The patients’ age and gender were considered as nuisance covariates. We also evaluated the correlations between the FW-DTI indices and the performance status and disease duration.

Results: Significant negative correlations between the serum levels of several autoantibody titers and DTI indices were identified, mainly in the right frontal operculum. The disease duration showed significant negative correlations with both FAt and FA in the right frontal operculum. The changes in the FW-corrected DTI indices were observed over a wider extent compared to the conventional DTI indices.

Conclusions: These results demonstrate the value of using DTI to assess the microstructure of ME/CFS. The abnormalities of right frontal operculum may be a diagnostic marker for ME/CFS.

Source: Kimura Y, Sato W, Maikusa N, Ota M, Shigemoto Y, Chiba E, Arizono E, Maki H, Shin I, Amano K, Matsuda H, Yamamura T, Sato N. Free-water-corrected diffusion and adrenergic/muscarinic antibodies in myalgic encephalomyelitis/chronic fatigue syndrome. J Neuroimaging. 2023 May 27. doi: 10.1111/jon.13128. Epub ahead of print. PMID: 37243973. https://pubmed.ncbi.nlm.nih.gov/37243973/

Suppressed immune and metabolic responses to intestinal damage-associated microbial translocation in myalgic encephalomyelitis/chronic fatigue syndrome

Highlights:

  • Elevation of FABP2, a marker of intestinal cell damage in ME/CFS.
  • Absence of optimal acute-phase LBP and sCD14 anti-microbial responses in ME/CFS.
  • Compensatory but inadequate B cell response to microbial translocation in ME/CFS.
  • Enhanced IL-10 regulatory response may drive the observed immunosuppression.
  • Glucose and citrate metabolic dysfunction in ME/CFS may link the IL-10 activation and suppressed anti-microbial responses.

Abstract:

The etiology and mechanism of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) are poorly understood and no biomarkers have been established. Specifically, the relationship between the immunologic, metabolic, and gastrointestinal abnormalities associated with ME/CFS and their relevance to established symptoms of the condition remain unclear.

Relying on data from two independent cohorts of ME/CFS and control study participants, one at rest and one undergoing an exercise challenge, we identify a state of suppressed acute-phase innate immune response to microbial translocation in conjunction with a compromised gut epithelium. This immunosuppression, along with observed enhancement of compensatory antibody responses to counter the microbial translocation, was associated with and may be mediated by alterations in glucose and citrate metabolism and an IL-10 immunoregulatory response. Our findings provide novel insights into mechanistic pathways, biomarkers, and potential therapeutic targets in ME/CFS, including in the context of exertion, with relevance to both intestinal and extra-intestinal symptoms.

Source: Melanie Uhde, Alyssa C. Indart, Peter H.R. Green, Robert H. Yolken, Dane B. Cook, Sanjay K. Shukla, Suzanne D. Vernon, Armin Alaedini.
Suppressed immune and metabolic responses to intestinal damage-associated microbial translocation in myalgic encephalomyelitis/chronic fatigue syndrome. Brain, Behavior, & Immunity – Health, 2023, 100627. ISSN 2666-3546, https://doi.org/10.1016/j.bbih.2023.100627.
https://www.sciencedirect.com/science/article/pii/S2666354623000418 (Full text)