Tag: 2025

Defining a High-Quality Myalgic Encephalomyelitis/Chronic Fatigue Syndrome cohort in UK Biobank

Abstract:

Background: Progress in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) research is being slowed by the relatively small-scale studies being performed whose results are often not replicated. Progress could be accelerated by analyses of large population-scale projects, such as UK Biobank (UKB), which provide extensive phenotype and genotype data linked to both ME/CFS cases and controls.

Methods: Here, we analysed the overlap and discordance among four UKB-defined ME/CFS cohorts, and additional questionnaire data when available.

Results: A total of 5,354 UKB individuals were linked to at least one piece of evidence of MECFS, a higher proportion (1.1%) than most prevalence estimates. Only a third (36%; n=1,922) had 2 or more pieces of evidence for MECFS, in part due to data missingness. For the same UKB participant, ME/CFS status defined by ICD-10 (International Classification of Diseases, Tenth Revision) code G93.3 (Post-viral fatigue syndrome) was most likely to be supported by another data type (72%); ME/CFS status defined by Pain Questionnaire responses is least likely to be supported (43%), in part due to data missingness.

Conclusions: We conclude that ME/CFS status in UKB, and potentially other biobanks, is best supported by multiple, and not single, lines of evidence. Finally, we raise the estimated ME/CFS prevalence in the UK to 410,000 using the most consistent evidence for ME/CFS status, and accounting for those who had no opportunity to participate in UKB due to being bed- or house-bound.

Source: Samms GL, Ponting CP. Defining a High-Quality Myalgic Encephalomyelitis/Chronic Fatigue Syndrome cohort in UK Biobank. NIHR Open Res. 2025 Apr 28;5:39. doi: 10.3310/nihropenres.13956.1. PMID: 40443420; PMCID: PMC12120426. https://pmc.ncbi.nlm.nih.gov/articles/PMC12120426/ (Full text)

HERV Dysregulation in a Case of Myalgic Encephalomyelitis and Multiple Sclerosis Responsive to Rituximab

Abstract:

This article summarizes the case of 30-year-old male diagnosed with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) and its longitudinal follow-up, which provided a secondary diagnosis of Multiple Sclerosis (MS) eight years later. The most impactful result was his response to rituximab treatment after the systematic failure of prior treatments.

Although the expression of endogenous retroviral proteins has been associated with autoimmunity, the patient did not show increased expression of the toxic protein HERV (human endogenous retrovirus)-W ENV, a target of the ongoing clinical trials with temelimab in MS and long COVID-19 cases. However, genome-wide HERV transcriptome analysis by high density microarrays clearly revealed a distinct profile in the patient’s blood supportive of an altered immune system.

Limitations of the study include sub-optimal frequency of magnetic resonance imaging to monitor lesion progression, and similarly for reassessment of HERV profiles after rituximab. Overall, the coincidence of HERV alterations and the impactful response to rituximab presents the possibility of additional, more specific, therapeutic targets encoded by other HERV elements yet to be discovered.

Source: Martín-Martínez E, Gil-Perotin S, Giménez-Orenga K, Barea-Moya L, Oltra E. HERV Dysregulation in a Case of Myalgic Encephalomyelitis and Multiple Sclerosis Responsive to Rituximab. Int J Mol Sci. 2025 May 20;26(10):4885. doi: 10.3390/ijms26104885. PMID: 40430026; PMCID: PMC12111851. https://pmc.ncbi.nlm.nih.gov/articles/PMC12111851/ (Full text)

Evaluating the Causal Role of Genetically Inferred Immune Cells and Inflammatory Cytokines on Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Abstract:

Background/Objectives: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a multifaceted and diverse disorder with an ambiguous etiology. Recent evidence indicates that immune system impairment and inflammatory mechanisms are pivotal to the initiation and advancement of ME/CFS. Nonetheless, the causal relationships among these factors remain inadequately comprehended.

Methods: This study investigated the causative contributions of immunological dysfunction and inflammatory variables in ME/CFS utilizing genome-wide association study (GWAS) data. We employed Mendelian randomization (MR) to investigate associations between 91 inflammatory cytokines, 731 immune cell characteristics, and the risk of ME/CFS. Summary statistics for immune cell traits and inflammatory cytokines were sourced from European GWAS cohorts (n = 3757 and n = 14,824, respectively), while ME/CFS data were obtained from the UK Biobank (n = 462,933, including 2076 cases). We predominantly employed the inverse variance weighted (IVW) approach, complemented by MR-Egger, weighted median, BWMR, and MR-RAPS tests to guarantee robust and precise outcomes.

Results: The study revealed significant causal links between various inflammatory factors, immune cell characteristics, and the risk of ME/CFS. Increased CXCL5 and CCL20 levels were significantly linked to a higher risk of ME/CFS, while elevated TNF levels were inversely related to ME/CFS risk. Furthermore, 13 immune cell characteristics were identified as having substantial causal associations with the likelihood of ME/CFS. These data are supportive of the causality that immune system dysfunction and inflammatory variables play a pivotal role in the development of ME/CFS.

Conclusions: This study provides new insights into the causal role of immune system dysfunction in the development of ME/CFS, contributing to a deeper understanding of its underlying mechanisms. These results offer a foundation for identifying diagnostic biomarkers and developing targeted therapeutic strategies. Future research should validate these findings using multi-center cohort studies and further investigate the mechanisms behind key factors to enable the development of personalized treatment approaches.

Source: Duan L, Yang J, Zhao J, Chen Z, Yang H, Cai D. Evaluating the Causal Role of Genetically Inferred Immune Cells and Inflammatory Cytokines on Myalgic Encephalomyelitis/Chronic Fatigue Syndrome. Biomedicines. 2025 May 15;13(5):1200. doi: 10.3390/biomedicines13051200. PMID: 40427027; PMCID: PMC12109099. https://pmc.ncbi.nlm.nih.gov/articles/PMC12109099/ (Full text)

Multimodal Web-Based Telerehabilitation for Patients With Post-COVID-19 Condition: Protocol for a Randomized Controlled Trial

Abstract:

Background: Patients with post-COVID-19 condition (PCC) experience persistent, long-term health consequences following SARS-CoV-2 infection, including fatigue, hyperventilation, cognitive impairment, and limitations in daily activities. There is emerging evidence suggesting that exercise and respiratory therapy-based telerehabilitation is safe and could potentially improve physical capacity while reducing health care costs.

Objective: This study aims to evaluate the superiority of a multimodal, symptom-titrated telerehabilitation program over standard care in patients with PCC who are severely affected, using the highest oxygen uptake rate (VO2peak [mL/min/kg]) achieved during the cardiopulmonary exercise test (CPET) and minute ventilation/carbon dioxide production slope (VE/VCO2 [full slope]) as primary outcomes. In addition, this study seeks to provide novel insights into the clinical and physiological adaptations associated with PCC, informing future rehabilitation strategies.

Methods: This prospective, randomized, waitlist-controlled trial was approved by the Rhineland-Palatinate Medical Association ethics committee. All procedures comply with the Declaration of Helsinki. This study comprises 3 examination time points, which include patient-reported outcomes, clinical assessments, and a CPET. It is structured into an 8-week intervention phase followed by an 8-week follow-up phase. Following baseline assessment, patients will be randomly assigned to either the intervention group (IG) or the control group (CG). During the intervention phase, IG participants will receive a web-based, multimodal, symptom-titrated telerehabilitation program consisting of sports medicine consultations, weekly teleconsultations, a structured pacing approach, and exercise and respiratory therapy. In contrast, CG participants will receive treatment as usual, which includes a single sports medicine consultation on healthy habits and a self-directed pacing approach for managing symptoms and daily activities. During the follow-up phase, IG participants will continue training independently without teleconsultations, whereas CG participants will undergo the same telerehabilitation intervention as the IG. A follow-up assessment will be conducted for both groups to evaluate long-term effects. This study adheres to the SPIRIT (Standard Protocol Items: Recommendations for Interventional Trials) guidelines and follows the Consensus on Exercise Reporting Template.

Results: Recruitment began in August 2023 and was extended until March 2025. As of March 2025, 80 participants have been recruited, and data analysis is ongoing. Final results are expected by December 2025, with a cross-sectional analysis of baseline data anticipated by July 2025.

Conclusions: This study is the first randomized controlled trial investigating the effectiveness of multimodal and symptom-titrated telerehabilitation in patients with PCC who are severely affected. The integration of various objective diagnostic systems will provide valuable insights into emerging postviral fatigue syndromes, supporting the development of CPET-based diagnostics, personalized rehabilitation strategies, and future research on long-term telerehabilitation effectiveness. The findings will be disseminated through peer-reviewed publications, professional networks, and patient advocacy groups to ensure scientific, clinical, and public impact.

Trial registration: German Clinical Trials Register (DRKS) DRKS00032394; https://drks.de/search/de/trial/DRKS00032394.

Source: Tomaskovic A, Weber V, Ochmann DT, Neuberger EW, Lachtermann E, Brahmer A, Haller N, Hillen B, Enders K, Eggert V, Zeier P, Lieb K, Simon P. Multimodal Web-Based Telerehabilitation for Patients With Post-COVID-19 Condition: Protocol for a Randomized Controlled Trial. JMIR Res Protoc. 2025 May 21;14:e65044. doi: 10.2196/65044. PMID: 40397936. https://www.researchprotocols.org/2025/1/e65044 (Full text)

Impact of the COVID-19 Pandemic and the 2021 National Institute for Health and Care Excellence Guidelines on Public Perspectives Toward Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: Thematic and Sentiment Analysis on Twitter (Rebranded as X)

Abstract:

Background: Myalgic encephalomyelitis (ME), also referred to as chronic fatigue syndrome (CFS), is a complex illness that typically presents with disabling fatigue and cognitive and functional impairment. The etiology and management of ME/CFS remain contentious and patients often describe their experiences through social media.

Objective: We explored public discourse on Twitter (rebranded as X) to understand the concerns and priorities of individuals living with ME/CFS, with a focus on (1) the COVID-19 pandemic and (2) publication of the 2021 UK National Institute for Health and Care Excellence (NICE) guidelines on the diagnosis and management of ME/CFS.

Methods: We used the Twitter application programming interface to collect tweets related to ME/CFS posted between January 1, 2010, and January 30, 2024. Tweets were sorted into 3 chronological periods (pre-COVID-19 pandemic, post-COVID-19 pandemic, and post-UK 2021 NICE Guidelines publication). A Robustly Optimized Bidirectional Embedding Representations from Transformers Pretraining Approach (RoBERTa) language processing model was used to categorize the sentiment of tweets as positive, negative, or neutral. We identified tweets that mentioned COVID-19, the UK NICE guidelines, and key themes identified through latent Dirichlet allocation (ie, fibromyalgia, research, and treatment). We sampled 1000 random tweets from each theme to identify subthemes and representative quotes.

Results: We retrieved 906,404 tweets, of which 427,824 (47.2%) were neutral, 369,371 (40.75%) were negative, and 109,209 (12.05%) were positive. Over time, both the proportion of negative and positive tweets increased, and the proportion of neutral tweets decreased (P<.001 for all changes). Tweets mentioning fibromyalgia acknowledged similarities with ME/CFS, stigmatization associated with both disorders, and lack of effective treatments. Treatment-related tweets often described frustration with ME/CFS labeled as mental illness, dismissal of concerns by health care providers, and the need to seek out “good physicians” who viewed ME/CFS as a physical disorder. Tweets on research typically praised studies of biomarkers and biomedical therapies, called for greater investment in biomedical research, and expressed frustration with studies suggesting a biopsychosocial etiology for ME/CFS or supporting management with psychotherapy or graduated activity. Tweets about the UK NICE guidelines expressed frustration with the 2007 version that recommended cognitive behavioral therapy and graded exercise therapy, and a prolonged campaign by advocacy organizations to influence subsequent versions. Tweets showed high acceptance of the 2021 UK NICE guidelines, which were seen to validate ME/CFS as a biomedical disease and recommended against graded exercise therapy. Tweets about COVID-19 often noted overlaps between post-COVID-19 condition and ME/CFS, including claims of a common biological pathway, and advised there was no cure for either condition.

Conclusions: Our findings suggest research is needed to inform how best to support patients’ engagement with evidence-based care. Furthermore, while patient involvement with ME/CFS research is critical, unmanaged intellectual conflicts of interest may threaten the trustworthiness of research efforts.

Source: Khakban I, Jain S, Gallab J, Dharmaraj B, Zhou F, Lokker C, Abdelkader W, Zeraatkar D, Busse JW. Impact of the COVID-19 Pandemic and the 2021 National Institute for Health and Care Excellence Guidelines on Public Perspectives Toward Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: Thematic and Sentiment Analysis on Twitter (Rebranded as X). J Med Internet Res. 2025 May 21;27:e65087. doi: 10.2196/65087. PMID: 40397934. https://www.jmir.org/2025/1/e65087 (Full text)

Gastrointestinal Barrier Disruption in Post-COVID Syndrome Fatigue Patients

Abstract:

Background: Post-COVID Syndrome (PCS) is the term for a condition with persistent symptoms in a proportion of COVID-19 patients after asymptomatic, mild, or severe disease courses. Numbers vary, but the current estimate is that after COVID-19 approximately 10% develop PCS. The aim of our study was to evaluate the impact of SARS-CoV-2 infection on the gastrointestinal (GI) tract and associations with the development of PCS with fatigue, post-exertional malaise (PEM), orthostatic dysregulation, autonomous dysregulation, and/or neurocognitive dysregulation.

Methods: By combining medical record data from a prospective observational study with symptom analysis before, during, and after SARS-CoV-2 infection, we aimed to identify potential risk factors and predictive markers for PCS. Additionally, we analyzed blood, saliva, and stool samples from this well-characterized PCS patient cohort to biologically validate our findings.

Results: We identified significant associations between pre-existing GI complaints and the development of PCS Fatigue. PCS patients showed higher LBP/sCD14 ratios, lower IL-33 levels, and higher IL-6 levels compared to control groups. Our results highlight the critical role of the GI tract in PCS development of post-viral Fatigue.

Conclusion: We propose that the viral infection disrupts pathways related to the innate immune response and GI barrier function, evidenced by intestinal low-grade inflammation and GI barrier leakage. Monitoring GI symptoms and markers before, during, and after SARS-CoV-2 infection is crucial for identifying predictive clinical phenotypes in PCS. Understanding the interaction between viral infections, immune responses, and gut integrity could lead to more effective diagnostic and treatment strategies, ultimately reducing the burden on PCS patients.

Source: Rohrhofer J, Wolflehner V, Schweighardt J, Koidl L, Stingl M, Zehetmayer S, Séneca J, Pjevac P, Untersmayr E. Gastrointestinal Barrier Disruption in Post-COVID Syndrome Fatigue Patients. Allergy. 2025 May 15. doi: 10.1111/all.16593. Epub ahead of print. PMID: 40372110. https://onlinelibrary.wiley.com/doi/10.1111/all.16593 (Full text)

Disruptions in serotonin- and kynurenine pathway metabolism in post-COVID: biomarkers and treatment

Introduction:

This opinion article attempts to connect knowledge about post-COVID syndrome (PCS) gained in neuropsychiatry and immunology. It discusses some misunderstandings about PCS in light of the interplay between the serotonergic system and the kynurenine pathway (KP). From a new perspective, potential biomarkers for further research and therapeutic targets are identified.

Due to the severity and extent of PCS, researchers are urgently searching for its causes and treatments. For neurocognitive and autonomic nervous system problems such as present in PCS, it is common to encounter dysregulated neurotransmitter systems. Among the neurotransmitters, serotonin plays a special role in the immune system and in regulating inflammatory responses by central and peripheral mechanisms (–). Serotonin—also known as 5-hydroxytryptamine (5-HT)—is a neurotransmitter with a stimulating effect that influences memory, mood, self-confidence, sleep, emotion, orgasm and eating (–).

Serotonin not only binds to serotonergic receptors on neurons, but also to receptors on immune cells (, , , ). Many studies indicate that serotonin and its receptors, especially 5-HT3 receptors (one of the serotonin receptors), are involved in the pathogenesis of chronic inflammatory conditions (, , ). Therapeutic applications of 5-HT3 receptor antagonists for instance have been reported in rheumatoid arthritis (, , ). An essential amino acid in the serotonin system and also in the KP is tryptophan, a precursor of both serotonin and kynurenine (see Figure 1) and part of a regular diet (). The KP is a pathway creating an important energy factor and is modulated in conditions as infection and stress (, ). Kynurenine regulates the balance between two types of thymus cells (T-cells): regulatory T-cells (Treg-cells), and subsets of T helper 17 cells (Th17 cells) that produce cytokines and have a signaling function ().

In this opinion article I address the question whether disruptions in the serotonin- and kynurenine pathway metabolism lead to new biomarkers and treatment in PCS.

Source: Rus CP. Disruptions in serotonin- and kynurenine pathway metabolism in post-COVID: biomarkers and treatment. Front Neurol. 2025 Feb 13;16:1532383. doi: 10.3389/fneur.2025.1532383. PMID: 40027165; PMCID: PMC11869386. https://pmc.ncbi.nlm.nih.gov/articles/PMC11869386/ (Full text)

Ignorance about post-exertional malaise and continued conflation of ME/CFS with chronic fatigue harms patients and stymies research progress

Dear Editor,

There are numerous issues with the opinion piece by Miller and coauthors. Most concern longstanding fallacies about the nature of ME/CFS and what patients believe about their illness, which — again — need to be corrected. I’d like to focus on just one: The defining and cardinal feature of ME/CFS is not fatigue, but rather post-exertional malaise (PEM).

PEM, sometimes referred to as post-exertional symptom exacerbation (PESE), can be defined as episodes during which people with ME/CFS experience significant worsening of existing symptoms and/or onset of new symptoms following amounts of physical or mental exertion or sensory stimuli that they could easily tolerate before the illness [1]. The length and severity of an episode of PEM are out of proportion to the amount of exertion or stimulus that triggered it; in severe or very severe ME/CFS patients, PEM may be triggered by, for example, short conversations with their carers or brief exposure to bright light, and these episodes may last week, months, or longer.

PEM remains poorly understood, but the concept and terminology have over recent years become much more mainstream, owing to the high prevalence of PEM in long covid [2]. The consensus opinion among ME/CFS patients is that daily activities and sensory input should be managed in such a way as to minimise PEM, because PEM severely impacts quality of life and can in some cases lead to further long-term deterioration in patients’ health and functional capacity. This concept forms the basis of pacing, an energy management strategy recommended by NICE [3].

In their opinion piece, Miller and coauthors ignore PEM when listing common symptoms of ME/CFS. This is an attempt to continue framing this illness as belonging to a family of ‘fatiguing conditions’, which, along with other ‘medically unexplained symptoms’, they argue can be treated with psychological interventions and rehabilitation.

Read the rest of this letter here: https://www.bmj.com/content/389/bmj.r977/rr-6

The risk of blaming patients for their lack of recovery

Dear Editor,

In their article on the management of patients with severe myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), Miller et al. propose a biopsychosocial model in which “a gradual, controlled approach to increasing activity is an important part of rehabilitation.” This approach, however, is far from new and has been tested in randomized trials with limited success.

The PACE study, for example, examined fourteen sessions of cognitive behaviour therapy (CBT) or graded exercise therapy (GET), each combined with specialist medical care. Treatment aimed to help ME/CFS patients gradually resume physical activities, address unhelpful cognitions, and reverse deconditioning. Recovery rates for GET and CBT were low and did not differ significantly from the control group, with rates of 4%, 7%, and 3%, respectively, as defined by the study’s pre-registered recovery criteria. [1] Employment and fitness data also showed no clinically significant improvement. [2]

Read the full letter by Michiel Tack here: https://www.bmj.com/content/389/bmj.r977/rr-3

How a Clinician Makes a Diagnosis for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS)

Abstract:

This chapter describes how a clinician with experience of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) makes a diagnosis of the condition in the absence of a routine laboratory diagnostic test.

Source: Vallings R. How a Clinician Makes a Diagnosis for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS). Methods Mol Biol. 2025;2920:3-11. doi: 10.1007/978-1-0716-4498-0_1. PMID: 40372674. https://link.springer.com/protocol/10.1007/978-1-0716-4498-0_1