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Keywords = myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS)

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10 pages, 220 KiB  
Perspective
Reframing Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS): Biological Basis of Disease and Recommendations for Supporting Patients
by Priya Agarwal and Kenneth J. Friedman
Healthcare 2025, 13(15), 1917; https://doi.org/10.3390/healthcare13151917 - 5 Aug 2025
Abstract
Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a worldwide challenge. There are an estimated 17–24 million patients worldwide, with an estimated 60 percent or more who have not been diagnosed. Without a known cure, no specific curative medication, disability lasting years to being life-long, [...] Read more.
Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a worldwide challenge. There are an estimated 17–24 million patients worldwide, with an estimated 60 percent or more who have not been diagnosed. Without a known cure, no specific curative medication, disability lasting years to being life-long, and disagreement among healthcare providers as to how to most appropriately treat these patients, ME/CFS patients are in need of assistance. Appropriate healthcare provider education would increase the percentage of patients diagnosed and treated; however, in-school healthcare provider education is limited. To address the latter issue, the New Jersey Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Association (NJME/CFSA) has developed an independent, incentive-driven, learning program for students of the health professions. NJME/CFSA offers a yearly scholarship program in which applicants write a scholarly paper on an ME/CFS-related topic. The efficacy of the program is demonstrated by the 2024–2025 first place scholarship winner’s essay, which addresses the biological basis of ME/CFS and how the healthcare provider can improve the quality of life of ME/CFS patients. For the reader, the essay provides an update on what is known regarding the biological underpinnings of ME/CFS, as well as a medical student’s perspective as to how the clinician can provide care and support for ME/CFS patients. The original essay has been slightly modified to demonstrate that ME/CFS is a worldwide problem and for publication. Full article
18 pages, 278 KiB  
Review
Biomarkers over Time: From Visual Contrast Sensitivity to Transcriptomics in Differentiating Chronic Inflammatory Response Syndrome and Myalgic Encephalomyelitis/Chronic Fatigue Syndrome
by Ming Dooley
Int. J. Mol. Sci. 2025, 26(15), 7284; https://doi.org/10.3390/ijms26157284 - 28 Jul 2025
Viewed by 363
Abstract
Chronic inflammatory response syndrome (CIRS) and Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) are debilitating multisystem illnesses that share overlapping symptoms and molecular patterns, including immune dysregulation, mitochondrial impairment, and vascular dysfunction. This review provides a chronological synthesis of biomarker development in CIRS, tracing its [...] Read more.
Chronic inflammatory response syndrome (CIRS) and Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) are debilitating multisystem illnesses that share overlapping symptoms and molecular patterns, including immune dysregulation, mitochondrial impairment, and vascular dysfunction. This review provides a chronological synthesis of biomarker development in CIRS, tracing its evolution from early functional tests such as visual contrast sensitivity (VCS) to advanced transcriptomic profiling. Drawing on peer-reviewed studies spanning two decades, we examine the layered integration of neuroendocrine, immunologic, metabolic, and genomic markers that collectively support a multisystem model of innate immune activation specific to environmentally acquired illness. Particular focus is given to the Gene Expression: Inflammation Explained (GENIE) platform’s use of transcriptomics to classify disease stages and distinguish CIRS from other fatiguing conditions. While ME/CFS research continues to explore overlapping pathophysiologic features, it has yet to establish a unified diagnostic model with validated biomarkers or exposure-linked mechanisms. As a result, many patients labeled with ME/CFS may, in fact, represent unrecognized CIRS cases. This review underscores the importance of structured biomarker timelines in improving differential diagnosis and guiding treatment in complex chronic illness and highlights the reproducibility of the CIRS framework in contrast to the diagnostic ambiguity surrounding ME/CFS. Full article
21 pages, 2776 KiB  
Article
Comparing DNA Methylation Landscapes in Peripheral Blood from Myalgic Encephalomyelitis/Chronic Fatigue Syndrome and Long COVID Patients
by Katie Peppercorn, Sayan Sharma, Christina D. Edgar, Peter A. Stockwell, Euan J. Rodger, Aniruddha Chatterjee and Warren P. Tate
Int. J. Mol. Sci. 2025, 26(14), 6631; https://doi.org/10.3390/ijms26146631 - 10 Jul 2025
Viewed by 1600
Abstract
Post-viral conditions, Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) and Long COVID (LC), share > 95% of their symptoms, but the connection between disturbances in their underlying molecular biology is unclear. This study investigates DNA methylation patterns in peripheral blood mononuclear cells (PBMC) from patients [...] Read more.
Post-viral conditions, Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) and Long COVID (LC), share > 95% of their symptoms, but the connection between disturbances in their underlying molecular biology is unclear. This study investigates DNA methylation patterns in peripheral blood mononuclear cells (PBMC) from patients with ME/CFS, LC, and healthy controls (HC). Reduced Representation Bisulphite Sequencing (RRBS) was applied to the DNA of age- and sex-matched cohorts: ME/CFS (n = 5), LC (n = 5), and HC (n = 5). The global DNA methylomes of the three cohorts were similar and spread equally across all chromosomes, except the sex chromosomes, but there were distinct minor changes in the exons of the disease cohorts towards more hypermethylation. A principal component analysis (PCA) analysing significant methylation changes (p < 0.05) separated the ME/CFS, LC, and HC cohorts into three distinct clusters. Analysis with a limit of >10% methylation difference and at p < 0.05 identified 214 Differentially Methylated Fragments (DMF) in ME/CFS, and 429 in LC compared to HC. Of these, 118 DMFs were common to both cohorts. Those in promoters and exons were mainly hypermethylated, with a minority hypomethylated. There were rarer examples with either no change in methylation in ME/CFS but a change in LC, or a methylation change in ME/CFS but in the opposite direction in LC. The differential methylation in a number of fragments was significantly greater in the LC cohort than in the ME/CFS cohort. Our data reveal a generally shared epigenetic makeup between ME/CFS and LC but with specific, distinct changes. Differences between the two cohorts likely reflect the stage of the disease from onset (LC 1 year vs. ME/CFS 12 years), but specific changes imposed by the SARS-CoV-2 virus in the case of the LC patients cannot be discounted. These findings provide a foundation for further studies with larger cohorts at the same disease stage and for functional analyses to establish clinical relevance. Full article
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7 pages, 404 KiB  
Brief Report
A Signal for Voice and Speech Abnormalities in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome
by Stephanie L. Grach, Jaime Seltzer and Diana M. Orbelo
J. Clin. Med. 2025, 14(14), 4847; https://doi.org/10.3390/jcm14144847 - 8 Jul 2025
Viewed by 2584
Abstract
Background/Objectives: Patients with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) may report abnormalities in voice and speech; however, no formal research has been conducted in this area. Methods: An online mixed-methods survey was completed by 685 people with ME/CFS. A total of 302 [...] Read more.
Background/Objectives: Patients with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) may report abnormalities in voice and speech; however, no formal research has been conducted in this area. Methods: An online mixed-methods survey was completed by 685 people with ME/CFS. A total of 302 respondents completed the qualitative component (44.09%). Questions assessed disease experience with ME/CFS and post-exertional malaise without prompting on specific symptoms. Within the qualitative results, a search of the terms “speech, voice,” “words,” and “speak” was conducted. Results: Excluding neurocognitive associations, colloquial phrases, and “speech therapy,” there were 38 mentions of the terms in the context of voice or speech changes across 28 unique qualitative survey responses (9.27%). Conclusions: A notable portion of respondents reported voice or speech changes when responding to open-ended qualitative questions about their disease experience. More research is needed regarding the implications of voice and speech anomalies in ME/CFS pathology and disease monitoring. Full article
(This article belongs to the Special Issue POTS, ME/CFS and Long COVID: Recent Advances and Future Direction)
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12 pages, 3191 KiB  
Article
Systems Modeling Reveals Shared Metabolic Dysregulation and Potential Treatments in ME/CFS and Long COVID
by Gong-Hua Li, Fei-Fei Han, Efthymios Kalafatis, Qing-Peng Kong and Wenzhong Xiao
Int. J. Mol. Sci. 2025, 26(13), 6082; https://doi.org/10.3390/ijms26136082 - 25 Jun 2025
Viewed by 6966
Abstract
Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) and Long COVID are complex multisystem conditions that pose significant challenges in healthcare. Accumulated research evidence suggests that ME/CFS and Long COVID exhibit overlapping metabolic symptoms, indicating potential shared metabolic dysfunctions. This study aims to systematically explore shared [...] Read more.
Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) and Long COVID are complex multisystem conditions that pose significant challenges in healthcare. Accumulated research evidence suggests that ME/CFS and Long COVID exhibit overlapping metabolic symptoms, indicating potential shared metabolic dysfunctions. This study aims to systematically explore shared metabolic disturbances in the muscle tissue of patients. Utilizing genome-wide metabolic modeling, we identified key metabolic irregularities in the muscle of patients with ME/CFS, notably the downregulation of the alanine and aspartate metabolism pathway and the arginine and proline metabolism pathway. Further, in silico knockout analyses suggested that supplementation with aspartate (ASP) or asparagine (ASN) could potentially ameliorate these metabolic deficiencies. In addition, assessments of metabolomic levels in Long COVID patients also showed the significant downregulation of ASP during post-exertional malaise (PEM) in both muscle and blood. Consequently, we propose that a combination of l-ornithine and l-aspartate (LOLA) is a potential candidate to alleviate metabolic symptoms in ME/CFS and Long COVID for future clinical trials. Full article
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19 pages, 3087 KiB  
Article
Neurodevelopment Genes Encoding Olduvai Domains Link Myalgic Encephalomyelitis to Neuropsychiatric Disorders
by Mauricio Arcos-Burgos, Mauricio Arcos-Holzinger, Claudio Mastronardi, Mario A. Isaza-Ruget, Jorge I. Vélez, Donald P. Lewis, Hardip Patel and Brett A. Lidbury
Diagnostics 2025, 15(12), 1542; https://doi.org/10.3390/diagnostics15121542 - 17 Jun 2025
Viewed by 1660
Abstract
Background/Objectives: The aetiology of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS), a chronic and severe debilitating disease with a complex phenotype, remains elusive. Associations with infectious diseases and autoimmune and neuropsychiatric disorders have been observed, without the identification of mechanisms. Previous studies suggest that genetic [...] Read more.
Background/Objectives: The aetiology of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS), a chronic and severe debilitating disease with a complex phenotype, remains elusive. Associations with infectious diseases and autoimmune and neuropsychiatric disorders have been observed, without the identification of mechanisms. Previous studies suggest that genetic predisposition plays a role, but results are difficult to replicate, with Genome-Wide Association Studies of ME/CFS being challenging due to the relative rareness and heterogeneity of the disorder. Methods: We studied a well-defined Australian patient cohort diagnosed via the International Consensus Criteria, recruited by a specialist ME/CFS clinic. The whole-exome sequences of 77 patients were contrasted against genome variation in the 1000 Genome Project’s genome-matched population. Results: Significant associations with ME/CFS were harboured in genes that belong to the Neuroblastoma Breakpoint Family encoding Olduvai (DUF1220) domains, namely NBPF1 (rs3897177, p-value = 3.15 × 10−8), NBPF10 (rs1553120233, p-value = 9.262 × 10−13), and NBPF16 (rs200632836, p-value = 1.04 × 10−6). Other significantly associated variants were detected in the ATR, RSPH10B, ADGRE5-CD97, and NTRK2 genes, among others. Replication of these results was attempted via a GWAS on raw data from a US cohort, which confirmed shared significant associations with variation identified in the PTPRD, CSMD3, RAPGEF5, DCC, ALDH18A1, GALNT16, UNC79, and NCOA3 genes. Conclusions: These genes are involved in cortical neurogenesis, brain evolution, and neuroblastoma, and have been implicated by several studies in schizophrenia and autism. The sharing of these associations by the two cohorts supports their validity and grants the necessity of future studies to evaluate the implications for ME/CFS aetiology. Full article
(This article belongs to the Section Pathology and Molecular Diagnostics)
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18 pages, 1560 KiB  
Article
Heat vs. Fatigue: Hyperthermia as a Possible Treatment Option for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS)
by Barbara Hochecker, Katja Matt, Melanie Scherer, Alica Meßmer, Alexander von Ardenne and Jörg Bergemann
Int. J. Mol. Sci. 2025, 26(11), 5339; https://doi.org/10.3390/ijms26115339 - 1 Jun 2025
Viewed by 3739
Abstract
The aetiology and pathophysiology of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) have not yet been clarified. Its exact diagnosis is also difficult because it has no biomarkers. This lack of knowledge leads to difficulties in treating the disease. In our work, we are attempting [...] Read more.
The aetiology and pathophysiology of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) have not yet been clarified. Its exact diagnosis is also difficult because it has no biomarkers. This lack of knowledge leads to difficulties in treating the disease. In our work, we are attempting to counteract this problem by analysing the central cellular mechanisms in ME/CFS patients and comparing them with those of healthy individuals. This pilot study provides a small glimpse into the journey of nine people with ME/CFS—more specifically, how their peripheral blood mononuclear cells (PBMCs) responded immediately after a session of whole-body hyperthermia (WBH). The clinical effect of WBH has already been investigated in other studies on the treatment of ME/CFS, and these studies have provided valuable insights into its potential benefits. The present study is concerned with the investigation of cellular parameters, namely autophagy, mitochondrial function and mRNA expression, before and after WBH. The results suggest that ME/CFS patients may have higher autophagy-related protein light chain 3 (LC3)-II levels and increased mitochondrial function compared with healthy individuals. A whole-body hyperthermia session could lead to a reduction in LC3-II levels, resulting in a reversion to the levels observed in healthy donors. In the case of mitochondrial parameters, hyperthermia could lead to an increase in the measured parameters. This pilot study is a continuation of a previously published study in which only the isolated cells of ME/CFS patients and a healthy control group were treated with hyperthermia. Full article
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16 pages, 1306 KiB  
Article
The Effect on Quality of Life of Therapeutic Plasmapheresis and Intravenous Immunoglobulins on a Population of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Patients with Elevated β-Adrenergic and M3-Muscarinic Receptor Antibodies—A Pilot Study
by Boglárka Oesch-Régeni, Nicolas Germann, Georg Hafer, Dagmar Schmid and Norbert Arn
J. Clin. Med. 2025, 14(11), 3802; https://doi.org/10.3390/jcm14113802 - 29 May 2025
Viewed by 2843
Abstract
Background/Objectives: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a debilitating condition with not fully understood causes, though evidence points to immune system involvement and possible autoimmunity. ME/CFS could be triggered by various infectious pathogens, like SARS-CoV-2; furthermore, a subset of the post-COVID-19 condition (PCC) [...] Read more.
Background/Objectives: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a debilitating condition with not fully understood causes, though evidence points to immune system involvement and possible autoimmunity. ME/CFS could be triggered by various infectious pathogens, like SARS-CoV-2; furthermore, a subset of the post-COVID-19 condition (PCC) patients fulfill the diagnostic criteria of ME/CFS. According to the Canadian Consensus Criteria (CCC), the presence of specific symptoms such as fatigue, post-exertional malaise, sleep dysfunction, pain, neurological/cognitive manifestations, and symptoms from at least two of the following categories lead to the diagnosis of ME/CFS: autonomic, neuroendocrine, and immune manifestation. In this study, the patient selection was based on the identification of ME/CFS patients with elevated autoantibodies, regardless of the triggering factor of their condition. Methods: The aim of this study was to identify ME/CFS patients among long COVID patients with elevated autoantibodies. In seven cases, plasmapheresis (PE) and intravenous immunoglobulins (IVIGs) with repetitive autoantibody measurements were applied: four PE sessions on days 1, 5, 30, and 60, and a low-dose IVIG therapy after each treatment. Antibodies were measured before the first PE and two weeks after the last PE session. To monitor clinical outcomes, the following somatic and psychometric follow-up assessments were conducted before the first PE, 2 weeks after the second, and 2 weeks after the last PE: the Schellong test, ISI (insomnia), FSS (fatigue), HADS (depression and anxiety), and EQ-5D-5L (quality of life) questionnaires. Results: There was a negative association between both the β2-adrenergic and M3-muscarinic receptor autoantibody concentration and the quality of life measurements assessed with the EQ-5D-5L questionnaire. Per 1 U/mL increase in the concentration levels of β2-adrenergic receptor antibodies or M3-muscarinic acetylcholine receptor antibodies, the EQ-5D-5L index score [−0.59 to 1] decreased by 0.01 (0.63%) or 0.02 (1.26%), respectively. There were no significant associations between the ISI, HADS, and FSS questionnaires and the β1-adrenergic and M4-muscarinic receptor antibodies titers. Conclusions: After a thorough selection of patients with present autoantibodies, this pilot study found negative associations concerning autoantibody concentration and somatic, as well as psychological wellbeing. To validate these promising feasibility study results—indicating the potential therapeutic potential of antibody-lowering methods—further investigation with larger sample sizes is needed. Full article
(This article belongs to the Section Clinical Laboratory Medicine)
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16 pages, 392 KiB  
Article
The Implications and Predictability of Sleep Reversal for People with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: A Machine Learning Approach
by Meghan P. Dietrich, Raam Pravin, Jacob Furst and Leonard A. Jason
Healthcare 2025, 13(11), 1255; https://doi.org/10.3390/healthcare13111255 - 26 May 2025
Viewed by 2415
Abstract
Background/Objectives: Impaired sleep is one of the core symptoms of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), yet the mechanisms and impact of sleep-related issues are poorly understood. Sleep dysfunctions for patients with ME/CFS include frequent napping, difficulties falling asleep, waking up early, and sleep [...] Read more.
Background/Objectives: Impaired sleep is one of the core symptoms of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), yet the mechanisms and impact of sleep-related issues are poorly understood. Sleep dysfunctions for patients with ME/CFS include frequent napping, difficulties falling asleep, waking up early, and sleep reversal patterns (e.g., sleeping throughout the day and staying awake throughout the night). The current study focuses on sleep reversal for patients with ME/CFS. Methods: We explored the symptoms and functional impairment of those with and without sleep reversal by analyzing the responses of a large international sample (N = 2313) using the DePaul Symptom Questionnaire (DSQ) and Medical Outcomes Study 36-item Short-Form Health Survey (SF-36). Results: We found that those in our Sleep Reversal group (N = 327) compared to those without sleep reversal (N = 1986) reported higher symptom burden for 53 out of 54 DSQ symptoms and greater impairments for all six SF-36 subscales. The most accurate predictors of sleep reversal included age (p < 0.05), body mass index (p < 0.05), eleven DSQ symptoms (p < 0.01), and two SF-36 subscales (p < 0.01). Conclusions: These features provide clues regarding some of the possible pathophysiological underpinnings of sleep reversal among those with ME/CFS. Full article
(This article belongs to the Special Issue Recent Advances in Sleep Disorder)
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14 pages, 786 KiB  
Article
The Relation Between Cardiac Output and Cerebral Blood Flow in ME/CFS Patients with a POTS Response During a Tilt Test
by C. (Linda) M. C. van Campen and Frans C. Visser
J. Clin. Med. 2025, 14(11), 3648; https://doi.org/10.3390/jcm14113648 - 22 May 2025
Viewed by 3857
Abstract
Background/Objectives: Orthostatic intolerance is prevalent in patients with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and is caused by an abnormal reduction in cerebral blood flow (CBF). In healthy controls (HCs), CBF is regulated complexly, and cardiac output (CO) is an important determinant of [...] Read more.
Background/Objectives: Orthostatic intolerance is prevalent in patients with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and is caused by an abnormal reduction in cerebral blood flow (CBF). In healthy controls (HCs), CBF is regulated complexly, and cardiac output (CO) is an important determinant of CBF. A review in HC showed that a 30% reduction in CO results in a 10% reduction in CBF. In contrast, we showed in ME/CFS patients with a normal HR (HR) and blood pressure response during a tilt test that CO and CBF decreased to a similar extent. The relation between CO and CBF in ME/CFS patients with postural orthostatic tachycardia syndrome (POTS) is unknown. Therefore, the aim of this study is to assess the relation between CBF and CO, in ME/CFS patients with POTS. The methods used in this retrospective study analyze this relation in a large group of patients. We also analyzed the influence of clinical data. A total of 260 ME/CFS patients with POTS underwent tilt testing with measurements of HR, BP, CBF, CO, and end-tidal PCO2. We measured CBF using extracranial Doppler flow velocity and vessel diameters obtained with a General Electric echo system, and suprasternal aortic flow velocities were measured using the same device. We recorded end-tidal PCO2 using a Nonin Lifesense device. Results: End-tilt HR and the HR increase were significantly higher in the patients with a %CO reduction ≥ −15% than in the other group. End-tilt CO was higher and the %CO reduction was lower in patients with %CO reduction ≥ −15% than in the other group. CBF data (supine, end-tilt and the %CBF reduction) were not different between the two patient groups. The use of HR increases and %SV reductions were not as discriminative as the %CO reduction. Conclusions: In ME/CFS patients with POTS during tilt testing with measurements of both the CO and the CBF, two different patterns were observed: (1) appr. two-thirds of patients had an almost 1:1 relation between the %CBF reduction and the %CO reduction. (2) Appr. one-third of patients showed a limited reduction in CO together with a substantial increase in HR. In these patients, there was no relation between the CO and CBF reduction. These data suggest the presence of a hyperadrenergic response. Full article
(This article belongs to the Section Cardiology)
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15 pages, 643 KiB  
Case Report
HERV Dysregulation in a Case of Myalgic Encephalomyelitis and Multiple Sclerosis Responsive to Rituximab
by Eva Martín-Martínez, Sara Gil-Perotin, Karen Giménez-Orenga, Lucas Barea-Moya and Elisa Oltra
Int. J. Mol. Sci. 2025, 26(10), 4885; https://doi.org/10.3390/ijms26104885 - 20 May 2025
Viewed by 1433
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 [...] Read more.
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. Full article
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13 pages, 2753 KiB  
Article
Evaluating the Causal Role of Genetically Inferred Immune Cells and Inflammatory Cytokines on Myalgic Encephalomyelitis/Chronic Fatigue Syndrome
by Lincheng Duan, Jingyi Yang, Junxin Zhao, Zhuoyang Chen, Hong Yang and Dingjun Cai
Biomedicines 2025, 13(5), 1200; https://doi.org/10.3390/biomedicines13051200 - 15 May 2025
Viewed by 1445
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 [...] Read more.
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. Full article
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44 pages, 549 KiB  
Opinion
The PACE Trial’s GET Manual for Therapists Exposes the Fixed Incremental Nature of Graded Exercise Therapy for ME/CFS
by Mark Vink and Katarzyna Partyka-Vink
Life 2025, 15(4), 584; https://doi.org/10.3390/life15040584 - 2 Apr 2025
Viewed by 3184
Abstract
The British National Institute for Health and Care Excellence (NICE) published its updated guidelines for myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) in October 2021. NICE concluded, after an extensive review of the literature, that graded exercise therapy (GET) is harmful and should not be [...] Read more.
The British National Institute for Health and Care Excellence (NICE) published its updated guidelines for myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) in October 2021. NICE concluded, after an extensive review of the literature, that graded exercise therapy (GET) is harmful and should not be used, and that cognitive behavioural therapy (CBT) is only an adjunctive and not a curative treatment. An article by White et al., which is written by 51 researchers, claims that there are eight anomalies in the review process and the interpretation of the evidence by NICE. In this article, we reviewed the evidence they used to support their claims. Their three most important claims are that NICE redefined the disease, that CBT and GET are effective, and that fixed incremental increases are not part of GET. However, our analysis shows that the disease was not redefined by NICE. Instead, it was redefined in the 1990s by a group of doctors, including a number of authors of White et al., when they erased the main characteristic of the disease (an abnormally delayed muscle recovery after trivial exertion, which, over the years, has evolved into post-exertional malaise) and replaced it with chronic disabling severe fatigue. Their own studies show that CBT and GET do not lead to a substantial improvement of the quality-of-life scores or a reduction in CFS symptom count, nor do they lead to objective improvement. Also, both treatments have a negative instead of a positive effect on work and disability status. Moreover, a recent systematic review, which included one of the authors of White et al., showed that ME/CFS patients remain severely disabled after treatment with CBT. Our analysis of, for example, the PACE trial’s GET manual for therapists exposes the fixed incremental nature of GET. Why the authors are not aware of that is unclear because eight of them were involved in the PACE trial. Three of them were centre leaders and its principal investigators, four others were also centre leaders, and another one was one of the three independent safety assessors of the trial. Moreover, many of these eight authors wrote, or were involved in writing, this manual. In conclusion, our analysis shows that the arguments that are used to claim that there are eight anomalies in the review process and the interpretation of the evidence by NICE are anomalous and highlight the absence of evidence for the claims that are made. Furthermore, our analysis not only exposes the fixed incremental nature of GET, but also of CBT for ME/CFS. Full article
(This article belongs to the Section Medical Research)
11 pages, 1018 KiB  
Review
Predisposing and Precipitating Factors in Epstein–Barr Virus-Caused Myalgic Encephalomyelitis/Chronic Fatigue Syndrome
by Leonard A. Jason and Ben Z. Katz
Microorganisms 2025, 13(4), 702; https://doi.org/10.3390/microorganisms13040702 - 21 Mar 2025
Viewed by 7452
Abstract
Long COVID following SARS-CoV-2 and Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) following infectious mononucleosis (IM) are two examples of post-viral syndromes. The identification of risk factors predisposing patients to developing and maintaining post-infectious syndromes may help uncover their underlying mechanisms. The majority of patients [...] Read more.
Long COVID following SARS-CoV-2 and Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) following infectious mononucleosis (IM) are two examples of post-viral syndromes. The identification of risk factors predisposing patients to developing and maintaining post-infectious syndromes may help uncover their underlying mechanisms. The majority of patients with ME/CFS report infectious illnesses before the onset of ME/CFS, with 30% of cases of ME/CFS due to IM caused by the Epstein–Barr virus. After developing IM, one study found 11% of adults had ME/CFS at 6 months and 9% had ME/CFS at 1 year. Another study of adolescents found 13% and 7% with ME/CFS at 6 and 12 months following IM, respectively. However, it is unclear which variables are potential risk factors contributing to the development and maintenance of ME/CFS following IM, because few prospective studies have collected baseline data before the onset of the triggering illness. The current article provides an overview of a study that included pre-illness predictors of ME/CFS development following IM in a diverse group of college students who were enrolled before the onset of IM. Our data set included an ethnically and sociodemographically diverse group of young adult students, and we were able to longitudinally follow these youths over time to better understand the risk factors associated with the pathophysiology of ME/CFS. General screens of health and psychological well-being, as well as blood samples, were obtained at three stages of the study (Stage 1—Baseline—when the students were well, at least 6 weeks before the student developed IM; Stage 2—within 6 weeks following the diagnosis of IM, and Stage 3—six months after IM, when they had either developed ME/CFS or recovered). We focused on the risk factors for new cases of ME/CFS following IM and found factors both at baseline (Stage 1) and at the time of IM (Stage 2) that predicted nonrecovery. We are now collecting seven-year follow-up data on this sample, as well as including cases of long COVID. The lessons learned in this prospective study are reviewed. Full article
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16 pages, 2849 KiB  
Article
An In-Depth Exploration of the Autoantibody Immune Profile in ME/CFS Using Novel Antigen Profiling Techniques
by Arnaud Germain, Jillian R. Jaycox, Christopher J. Emig, Aaron M. Ring and Maureen R. Hanson
Int. J. Mol. Sci. 2025, 26(6), 2799; https://doi.org/10.3390/ijms26062799 - 20 Mar 2025
Cited by 1 | Viewed by 5518
Abstract
Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a debilitating disorder characterized by serious physical and cognitive impairments. Recent research underscores the role of immune dysfunction, including the role of autoantibodies, in ME/CFS pathophysiology. Expanding on previous studies, we analyzed 7542 antibody–antigen interactions in ME/CFS [...] Read more.
Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a debilitating disorder characterized by serious physical and cognitive impairments. Recent research underscores the role of immune dysfunction, including the role of autoantibodies, in ME/CFS pathophysiology. Expanding on previous studies, we analyzed 7542 antibody–antigen interactions in ME/CFS patients using two advanced platforms: a 1134 autoantibody Luminex panel from Oncimmune and Augmenta Bioworks, along with Rapid Extracellular Antigen Profiling (REAP), a validated high-throughput method that measures autoantibody reactivity against 6183 extracellular human proteins and 225 human viral pathogen proteins. Unlike earlier reports, our analysis of 172 participants revealed no significant differences in autoantibody reactivities between ME/CFS patients and controls, including against GPCRs such as β-adrenergic receptors. However, subtle trends in autoantibody ratios between male and female ME/CFS subgroups, along with patterns of herpesvirus reactivation, suggest the need for broader and more detailed exploration. Full article
(This article belongs to the Special Issue Cellular and Molecular Mechanisms of Autoimmune Disorders)
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