Tag: 2025

Reframing Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS): Biological Basis of Disease and Recommendations for Supporting Patients

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, 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.

Source: Agarwal P, Friedman KJ. Reframing Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS): Biological Basis of Disease and Recommendations for Supporting Patients. Healthcare (Basel). 2025 Aug 5;13(15):1917. doi: 10.3390/healthcare13151917. PMID: 40805949. https://www.mdpi.com/2227-9032/13/15/1917 (Full text)

Circulating cell-free RNA signatures for the characterization and diagnosis of myalgic encephalomyelitis/chronic fatigue syndrome

Abstract:

People living with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) experience heterogeneous and debilitating symptoms that lack sufficient biological explanation, compounded by the absence of accurate, noninvasive diagnostic tools. To address these challenges, we explored circulating cell-free RNA (cfRNA) as a blood-borne bioanalyte to monitor ME/CFS. cfRNA is released into the bloodstream during cellular turnover and reflects dynamic changes in gene expression, cellular signaling, and tissue-specific processes.

We profiled cfRNA in plasma by RNA sequencing for 93 ME/CFS cases and 75 healthy sedentary controls, then applied machine learning to develop diagnostic models and advance our understanding of ME/CFS pathobiology. A generalized linear model with least absolute shrinkage selector operator regression trained on condition-specific signatures achieved a test-set AUC of 0.81 and an accuracy of 77%.

Immune cfRNA deconvolution revealed differences in platelet-derived cfRNA between cases and controls, as well as elevated levels of plasmacytoid dendritic, monocyte, and T cell-derived cfRNA in ME/CFS. Biological network analysis further implicated immune dysfunction in ME/CFS, with signatures of cytokine signaling and T cell exhaustion. These findings demonstrate the utility of RNA liquid biopsy as a minimally invasive tool for unraveling the complex biology behind chronic illnesses.

Source: Gardella AE, Eweis-LaBolle D, Loy CJ, Belcher ED, Lenz JS, Franconi CJ, Scofield SY, Grimson A, Hanson MR, De Vlaminck I. Circulating cell-free RNA signatures for the characterization and diagnosis of myalgic encephalomyelitis/chronic fatigue syndrome. Proc Natl Acad Sci U S A. 2025 Aug 19;122(33):e2507345122. doi: 10.1073/pnas.2507345122. Epub 2025 Aug 11. PMID: 40789036. https://pubmed.ncbi.nlm.nih.gov/40789036/

ME/CFS and PASC Patient-Derived Immunoglobulin Complexes Disrupt Mitochondrial Function and Alter Inflammatory Marker Secretion

Abstract:

Autoimmunity is a key clinical feature in both post-infectious Myalgic encephalomyelitis / chronic fatigue syndrome (ME/CFS) and Post-Acute Sequelae of COVID (PASC). Passive transfer of immunoglobulins from patients’ sera into mice induces some clinical features of PASC. IgG-induced transfer of disease phenotypes has long been appreciated, yet the exact mechanism of disease development remains largely elusive.

Here, we demonstrate that IgG isolated from post-infectious ME/CFS patients selectively induces mitochondrial fragmentation in human endothelial cells, thereby altering mitochondrial energetics. This effect is lost upon cleavage of IgG into its Fab and Fc fragments.

The digested Fab fragment from ME/CFS alone was able to alter the mitochondrial energetics, resembling the effect of intact IgG. In contrast, the Fc fragment alone induced a hypometabolic phenotype characterized by a trend towards reduced overall ATP content. IgG from ME/CFS and PASC patients induced distinct but separate cytokine secretion profiles in healthy PBMCs.

Proteomics analysis of IgG-bound immune complexes revealed significant changes within the immune complexes of ME/CFS patients, affecting extracellular matrix organization, while the same from PASC patients pointed towards alterations in hemostasis and blood clot regulation.

We demonstrate that IgGs from ME/CFS patients carry a chronic protective stress response that promotes mitochondrial adaptation via fragmentation, without altering mitochondrial ATP generation capacity in endothelial cells. Together, these results highlight a potential pathogenic role of IgG in post-infectious ME/CFS and point to novel therapeutic strategies targeting antibody-mediated metabolic dysregulation.

Source: Bhupesh Kumar Prusty, Zheng Liu, Claudia Hollmann, Sharada Kalanidhi, Andreas Schlosser, Stephanie Lammer, Georgy Nikolayshvili, E mils Edgars Basens, Liba Sokolovska, Zaiga Nora-Krukle, Robert K Naviaux, Gabriela Riemekasten, Rebekka Rust, Judith Bellmann, Friedemann Paul, Franziska Sotzny, Carmen Scheibenbogen. ME/CFS and PASC Patient-Derived Immunoglobulin Complexes Disrupt Mitochondrial Function and Alter Inflammatory Marker Secretion. medRxiv 2025.08.06.25332978; doi: https://doi.org/10.1101/2025.08.06.25332978 https://www.medrxiv.org/content/10.1101/2025.08.06.25332978v1 (Full text available as PDF file)

Functional and internalizing disorders co-aggregate with cardiometabolic and immune-related diseases within families: a population-based cohort study

Abstract:

Background: Functional disorders share familial risk with internalizing disorders such as generalized anxiety disorder and depression, and are comorbid with cardiometabolic and immune-related diseases. We investigated whether functional and internalizing disorders co-aggregate with these diseases in families to gain insight into the aetiology of functional and internalizing disorders.

Methods: We included 166,774 subjects (aged 3-94), from the population-based Lifelines Cohort Study, a Dutch general population cohort. We defined cases for three functional disorders (myalgic encephalomyelitis/chronic fatigue syndrome; ME/CFS, fibromyalgia, and irritable bowel syndrome; IBS), two internalizing disorders (major depressive disorder; MDD and generalized anxiety disorder; GAD), cardiometabolic diseases (obesity, metabolic associated steatotic liver disease, type 2 diabetes, hypertension and cardiovascular disease) and immune-related diseases (composite measures of auto-immune disease and atopy). We used logistic regression to model the prevalence of these disorders in the general population and in participants with affected relatives. Using these prevalence estimates, we assessed familial co-aggregation with (1) recurrence risk ratios (λR), and (2) familial correlations (rf).

Results: All functional and internalizing disorders co-aggregated with immune-related diseases (λR range 1.06-1.24). ME/CFS, FM, and MDD co-aggregated with most cardiometabolic diseases (λR range 1.00-1.23). MDD, fibromyalgia, and ME/CFS showed similar familial correlation patterns with both disease groups (rf range 0.12-0.44), while patterns of IBS and GAD were more variable.

Conclusions: Internalizing and functional disorders share familial risk with immune-related and cardiometabolic diseases. This suggests that risk factors relevant to immune-related and cardiometabolic diseases may also be relevant for FDs. Future studies should investigate such risk factors to identify novel treatment targets.

Source: Steen OD, Bos M, van Ockenburg SL, Zhou Y, Nolte IM, Snieder H, Kendler K, Rosmalen JGM, van Loo HM. Functional and internalizing disorders co-aggregate with cardiometabolic and immune-related diseases within families: a population-based cohort study. BMC Med. 2025 Aug 11;23(1):469. doi: 10.1186/s12916-025-04293-7. PMID: 40784894. https://bmcmedicine.biomedcentral.com/articles/10.1186/s12916-025-04293-7 (Full text)

Heightened innate immunity may trigger chronic inflammation, fatigue and post-exertional malaise in ME/CFS

Abstract:

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is characterized by unexplained fatigue, post-exertional malaise (PEM), and cognitive dysfunction. ME/CFS patients often report a prodrome consistent with infection. We present a multi-omics analysis based on plasma metabolomic and proteomic profiling, and immune responses to microbial stimulation, before and after exercise.

We report evidence of an exaggerated innate immune response after exposures to microbial antigens; impaired energy production involving the citric acid cycle, beta-oxidation of fatty acids, and urea cycle energy production from amino acids; systemic inflammation linked with lipid abnormalities; disrupted extracellular matrix homeostasis with release of endogenous ligands that promote inflammation; reduced cell-cell adhesion and associated gut dysbiosis; complement activation; redox imbalance reflected by disturbances in copper-dependent antioxidant pathways and dysregulation of the tryptophan-serotonin-kynurenine pathways.

Many of these underlying abnormalities worsened following exercise in ME/CFS patients, but not in healthy subjects; many abnormalities reinforced each other and several were correlated with the intensity of symptoms. Our findings may inform targeted therapeutic interventions for ME/CFS and PEM.

Source: Che X, Ranjan A, Guo C, Zhang K, Goldsmith R, Levine S, Moneghetti KJ, Zhai Y, Ge L, Mishra N, Hornig M, Bateman L, Klimas NG, Montoya JG, Peterson DL, Klein SL, Fiehn O, Komaroff AL, Lipkin WI. Heightened innate immunity may trigger chronic inflammation, fatigue and post-exertional malaise in ME/CFS. medRxiv [Preprint]. 2025 Jul 24:2025.07.23.25332049. doi: 10.1101/2025.07.23.25332049. PMID: 40778181; PMCID: PMC12330418. https://pmc.ncbi.nlm.nih.gov/articles/PMC12330418/ (Full text available as PDF file)

Initial findings from the DecodeME genome-wide association study of myalgic encephalomyelitis/chronic fatigue syndrome

Abstract:

Myalgic encephalomyelitis / chronic fatigue syndrome (ME/CFS) is a common, poorly understood disease that has no effective treatments, and has long been underserved by scientific research and national health systems. It is a sex-biased disease towards females that is often triggered by an infection, and its hallmark symptom is post-exertional malaise. People with ME/CFS often report their symptoms being disbelieved. The biological mechanisms causing ME/CFS remain unclear.
We recruited 21,620 ME/CFS cases and performed genome-wide association studies (GWAS) for up to 15,579 cases and 259,909 population controls with European genetic ancestry. In these GWAS, we discovered eight loci that are significantly associated with ME/CFS, including three near BTN2A2, OLFM4, and RABGAP1L genes that act in the response to viral or bacterial infection. Four of the eight loci (RABGAP1L, FBXL4, OLFM4, CA10) were associated at p < 0.05 with cases ascertained using post-exertional malaise and fatigue in the UK Biobank and the Netherlands biobank Lifelines. We found no evidence of sex-bias among discovered associations, and replicated in males two genetic signals (ARFGEF2, CA10) discovered in females. The ME/CFS association near CA10 colocalises with a known association to multisite chronic pain. We found no evidence that the eight ME/CFS genetic signals share common causal genetic variants with depression or anxiety.
Our findings suggest that both immunological and neurological processes are involved in the genetic risk of ME/CFS.
Source: DecodeME collaboration. Initial findings from the DecodeME genome-wide association study of myalgic encephalomyelitis/chronic fatigue syndrome. https://www.research.ed.ac.uk/en/publications/initial-findings-from-the-decodeme-genome-wide-association-study- (Full text available as PDF file)

Nutraceutical Supplementation Effects on Subjective Fatigue Symptoms in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: A Systematic Review

Abstract:

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a debilitating condition marked by severe, long-lasting fatigue and exhaustion that does not improve with rest. ME/CFS is reported in individuals of all ages and various racial, socioeconomic, and ethnic groups. This condition lacks standard treatment. Nutritional supplements and dietary interventions are often used to manage symptoms, but the efficacy of these interventions remains scarce in the current literature. This systematic review aims to evaluate and summarize recent evidence on nutrient supplementation and diet-based interventions in patients with ME/CFS sourced from clinical trial registries and article databases.

Registries improve the quality, integrity, and transparency of clinical trials by providing a standardized platform for reporting study design and results and, thus, reducing the biases related to selective reporting practices. Systematic reviews using these registries, therefore, are an efficient pathway to acquire current medical evidence for use in clinical decision-making and the development of practice guidance in various fields. ClinicalTrials.gov, Medline, PubMed, Cochrane, and Web of Science were systematically searched for interventional studies in which patients suffering from ME/CFS supplemented or altered their diet.

The results of this review showed several supplements that suggest improvement in patients’ symptomatology, including nicotinamide adenine dinucleotide (NADH), coenzyme Q10 (CoQ10), wasabi, and probiotics. However, many of these registered clinical trials did not employ the U.S. National Institutes of Health (NIH)’s National Institute of Neurological Disorders and Stroke (NINDS) suggested common data elements (CDEs). These standardized outcome-measuring tools allow the generalization and true comparison of the patient-reported outcomes.

Source: Brito EM, Bonifanti L, Patel R, Jimenez J, Junco J, Rozenfeld IR, Renesca V, Cheema AK. Nutraceutical Supplementation Effects on Subjective Fatigue Symptoms in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: A Systematic Review. Cureus. 2025 Jul 2;17(7):e87178. doi: 10.7759/cureus.87178. PMID: 40755709; PMCID: PMC12315604. https://pmc.ncbi.nlm.nih.gov/articles/PMC12315604/ (Full text)

Inflammation and Interferon Signatures in Peripheral B-Lymphocytes and Sera of Individuals With Fibromyalgia

Abstract:

Fibromyalgia (FM) is an idiopathic chronic disease characterized by widespread musculoskeletal pain, hyperalgesia and allodynia, often accompanied by fatigue, cognitive dysfunction and other symptoms. Autoimmunity and neuroinflammatory mechanisms have been suggested to play important roles in the pathophysiology of FM supported by recently identified interferon signatures in affected individuals. However, the contribution of different components in the immune system, such as the B-lymphocytes, in the progression to FM are yet unknown. Furthermore, there is a great need for biomarkers that may improve diagnostics of FM. Herein, we investigated the gene expression profile in peripheral B-cells, as well as a panel of inflammatory serum proteins, in 30 FM patients and 23 healthy matched control individuals. RNA sequence analysis revealed 60 differentially expressed genes when comparing the two groups.

The group of FM patients showed increased expression of twenty-five interferon-regulated genes, such as S100A8 and S100A9, VCAM, CD163, SERPINA1, ANXA1, and an increased interferon score. Furthermore, FM was associated with elevated levels of 19 inflammatory serum proteins, such as IL8, AXIN1, SIRT2 and STAMBP, that correlated with the FM severity score.

Together, the results shows that FM is associated with an interferon signature in B-cells and increased levels of a set of inflammatory serum proteins. Our findings bring further support for immune activation in the pathogenesis of FM and highlight candidate biomarkers for diagnosis and intervention in the management of FM.

Source: Fineschi S, Klar J, Gustafsson KA, Jonsson K, Karlsson B, Dahl N. Inflammation and Interferon Signatures in Peripheral B-Lymphocytes and Sera of Individuals With Fibromyalgia. Front Immunol. 2022 May 26;13:874490. doi: 10.3389/fimmu.2022.874490. PMID: 35693781; PMCID: PMC9177944. https://pmc.ncbi.nlm.nih.gov/articles/PMC9177944/ (Full text)

Defective peripheral B cell tolerance leads to dysregulated B cell responses in Fibromyalgia Syndrome

Abstract:

Fibromyalgia syndrome (FMS) is a chronic pain disorder characterised by widespread musculoskeletal pain, fatigue, and cognitive dysfunction, with no definitive biomarkers or mechanism-based treatments. Emerging evidence suggests that immune dysregulation may contribute to the FMS pathogenesis, particularly involving B cells, which have been implicated in autoantibody production and neuronal sensitisation. However, whether peripheral B cell tolerance, a critical safeguard against autoimmunity, is compromised in FMS remains unknown. Here, we combined high-resolution B cell receptor (BCR) repertoire sequencing, deep immunophenotyping, and functional assays in a well-characterised FMS cohort to uncover profound defects in peripheral B cell tolerance.

We reveal significant defects in peripheral B cell tolerance in FMS, including: (1) impaired naïve B cell anergy, marked by elevated CD21, CD22, and CD24 expression; (2) exaggerated proliferative responses and rapid CD24 downregulation upon stimulation; and (3) altered BCR selection patterns, with increased IGHV6-1/IGHJ6 usage, skewed class switching toward IGHA1, and enhanced clonal expansion. These features closely resemble immune pathology profiles observed in classical autoimmune diseases.

These findings redefine FMS as a disorder of immune dysregulation, with defective B cell tolerance contributing to disease mechanisms. The convergence of interferon-driven B cell activation, clonal expansion, and autoantibody production suggests shared pathways with classical autoimmune diseases. Our study provides a foundation for mechanism-based diagnostics and targeted immunomodulatory therapies, offering new avenues for intervention in this debilitating condition.

Source: Rachael Bashford-Rogers, Alexander Long, Antonio Choi Chiu et al. Defective peripheral B cell tolerance leads to dysregulated B cell responses in Fibromyalgia Syndrome, 18 June 2025, PREPRINT (Version 1) available at Research Square [https://doi.org/10.21203/rs.3.rs-6836742/v1] https://www.researchsquare.com/article/rs-6836742/v1 (Full text)

The sensitising effect of IgG in fibromyalgia syndrome is mediated by Mrgprb2 in mast cells

Abstract:

Fibromyalgia syndrome (FMS) is characterized by elevated levels of immunoglobulin G (IgG), altered bowel habits, and increased pain sensitivity, suggesting immune dysregulation, but the exact mechanism remains unclear. Here, we found that FMS-IgG binds to mast cells in a MRGPRX2/b2-dependent manner, leading to mast cell recruitment and IL-6 secretion.

Transferring serum-IgG from FMS patients to mice induced FMS-like symptoms and increased skin mast cells, indicating that FMS-IgG acts through mast cell activation. The ablation of mice Mrgprb2 mast cells or deleting Mrgprb2 receptors prevented IgG-induced heightened sensitivity to mechanical and cold stimuli. Stimulating human LAD2 cells with FMS IgG elicited MRGPRX2-dependent IL-6 production. Consistent with mice findings, mast cell density and tryptase levels increased in human FMS skin samples compared to healthy controls.

Taken together our results suggests that FMS IgG mediates hypersensitivity via activation of mast cells bearing the MRGPRX2 receptor and that these cells are a potential therapeutic target.

Source: Karla R. Sanchez, Jamie Burgess, Qin Zheng, Uazman Alam, Harvey Neiland, Richard Berwick, David Andersson, Samantha Korver, Anne Marshall, Andreas Goebel, Xinzhong Dong. The sensitising effect of IgG in fibromyalgia syndrome is mediated by Mrgprb2 in mast cells. bioRxiv 2025.05.15.652596; doi: https://doi.org/10.1101/2025.05.15.652596 https://www.biorxiv.org/content/10.1101/2025.05.15.652596v1.full (Full text)