Tag: Klimas

Autonomic Dysfunction in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS): Findings from the Multi-Site Clinical Assessment of ME/CFS (MCAM) Study in the USA

Abstract:

Background/Objectives: Symptoms of autonomic dysfunction are common in infection-associated chronic conditions and illnesses (IACCIs), including myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). This study aimed to evaluate autonomic symptoms and their impact on ME/CFS illness severity.
Methods: Data came from a multi-site study conducted in seven ME/CFS specialty clinics during 2012–2020. Autonomic dysfunction was assessed using the Composite Autonomic Symptom Scale 31 (COMPASS-31), medical history, and a lean test originally described by the National Aeronautics and Space Administration (NASA). Illness severity was assessed using Patient-Reported Outcomes Measurement Information System measures, the 36-item short-form, as well as the CDC Symptom Inventory. This analysis included 442 participants who completed the baseline COMPASS-31 assessment, comprising 301 individuals with ME/CFS and 141 healthy controls (HC).
Results: ME/CFS participants reported higher autonomic symptom burden than HC across three assessment tools (all p < 0.0001), including the COMPASS-31 total score (34.1 vs. 6.8) and medical history indicators [dizziness or vertigo (42.6% vs. 2.8%), cold extremities (38.6% vs. 5.7%), and orthostatic intolerance (OI, 33.9% vs. 0.7%)]. Among ME/CFS participants, 97% had at least one autonomic symptom. Those with symptoms in the OI, gastrointestinal, and pupillomotor domains had significantly higher illness severity than those without these symptoms.
Conclusions: ME/CFS patients exhibit a substantial autonomic symptom burden that correlates with greater illness severity. Individualized care strategies targeting dysautonomia assessment and intervention may offer meaningful improvements in symptom management and quality of life for those with ME/CFS and similar chronic conditions.
Source: Issa A, Lin J-MS, Chen Y, Attell J, Brimmer D, Bertolli J, Natelson BH, Lapp CW, Podell RN, Kogelnik AM, et al. Autonomic Dysfunction in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS): Findings from the Multi-Site Clinical Assessment of ME/CFS (MCAM) Study in the USA. Journal of Clinical Medicine. 2025; 14(17):6269. https://doi.org/10.3390/jcm14176269  https://www.mdpi.com/2077-0383/14/17/6269 (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)

Stress-Induced Changes in Immune Signatures in ME/CFS Patients Determined by Transcriptome Analysis

Abstract:

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a chronic, complex multi-organ illness characterized by unexplained debilitating fatigue and post-exertional malaise (PEM). We evaluated transcriptomic changes in peripheral blood mononuclear cells (PBMC) of ME/CFS patients undergoing an exercise challenge and explored the transcriptomic response to exercise and recovery in PBMC of ME/CFS patients, as compared to healthy controls using RNA sequencing technology. As transcriptomic changes in ME/CFS patients are still in the phase of discovery, analysis of data has to be stringent, and the most important results have to be validated by a different technology, such as real-time PCR or NanoString.

Source: Gamer J, Van Booven D, Zarnowski O, Perez M, Frank J, Pangeni RP, Collado F, Klimas NG, Oltra E, Nathanson L. Stress-Induced Changes in Immune Signatures in ME/CFS Patients Determined by Transcriptome Analysis. Methods Mol Biol. 2025;2920:103-112. doi: 10.1007/978-1-0716-4498-0_7. PMID: 40372680. https://link.springer.com/protocol/10.1007/978-1-0716-4498-0_7

Cognitive assessment in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS): a cognitive substudy of the multi-site clinical assessment of ME/CFS (MCAM)

Abstract:

Introduction: Patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) experience cognitive problems with attention, information processing speed, working memory, learning efficiency, and executive function. Commonly, patients report worsening of cognitive symptoms over time after physical and/or cognitive challenges. To determine, monitor, and manage longitudinal decrements in cognitive function after such exposures, it is important to be able to screen for cognitive dysfunction and changes over time in clinic and also remotely at home. The primary objectives of this paper were: (1) to determine whether a brief computerized cognitive screening battery will detect differences in cognitive function between ME/CFS and Healthy Controls (HC), (2) to monitor the impact of a full-day study visit on cognitive function over time, and (3) to evaluate the impact of exercise testing on cognitive dysfunction.

Methods: This cognitive sub-study was conducted between 2013 and 2019 across seven U.S. ME/CFS clinics as part of the Multi-Site Clinical Assessment of ME/CFS (MCAM) study. The analysis included 426 participants (261 ME/CFS and 165 HC), who completed cognitive assessments including a computerized CogState Brief Screening Battery (CBSB) administered across five timepoints (T0-T4) at the start of and following a full day in-clinic visit that included exercise testing for a subset of participants (182 ME/CFS and 160 HC). Exercise testing consisted of ramped cycle ergometry to volitional exhaustion. The primary outcomes are performance accuracy and latency (performance speed) on the computerized CBSB administered online in clinic (T0 and T1) and at home (T2-T4).

Results: No difference was found in performance accuracy between ME/CFS and HCs whereas information processing speed was significantly slower for ME/CFS at most timepoints with Cohen’s d effect sizes ranging from 0.3-0.5 (p < 0.01). The cognitive decline over time on all CBSB tasks was similar for patients with ME/CFS independent of whether exercise testing was included in the clinic visit.

Conclusion: The challenges of a clinic visit (including cognitive testing) can lead to further cognitive deficits. A single short session of intense exercise does not further reduce speed of performance on any CBSB tasks.

Source: Lange G, Lin JS, Chen Y, Fall EA, Peterson DL, Bateman L, Lapp C, Podell RN, Natelson BH, Kogelnik AM, Klimas NG, Unger ER. Cognitive assessment in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS): a cognitive substudy of the multi-site clinical assessment of ME/CFS (MCAM). Front Neurosci. 2024 Nov 1;18:1460157. doi: 10.3389/fnins.2024.1460157. PMID: 39554847; PMCID: PMC11565701. https://pmc.ncbi.nlm.nih.gov/articles/PMC11565701/ (Full text)

Chronic Overlapping Pain Conditions in people with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS): a sample from the Multi-site Clinical Assessment of ME/CFS (MCAM) study

Abstract:

Background: Chronic overlapping pain conditions (COPCs), pain-related conditions that frequently occur together, may occur in patients with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and could impact illness severity. This study aimed to identify comorbid COPCs in patients with ME/CFS and evaluate their impact on illness severity.

Methods: We used data from 923 participants in the Multi-Site Clinical Assessment of ME/CFS study, conducted in seven U.S. specialty clinics between 2012 and 2020, who completed the baseline assessment (595 ME/CFS and 328 healthy controls (HC)). COPCs included chronic low back pain (cLBP), chronic migraine/headache (cMHA), fibromyalgia (FM), interstitial cystitis/irritable bladder (IC/IB), irritable bowel syndrome (IBS), temporomandibular disorder (TMD). Illness severity was assessed through questionnaires measuring symptoms and functioning. Multivariate analysis of variance and analysis of covariance models were used for analyses. Log-binomial regression analyses were used to compute prevalence of COPCs and prevalence ratios (PR) between groups with 95% confidence intervals. Both unadjusted and adjusted results with age and sex are presented.

Results: 76% of participants with ME/CFS had at least one COPCs compared to 17.4% of HC. Among ME/CFS participants, cMHA was most prevalent (48.1%), followed by FM (45.0%), cLBP (33.1%), and IBS (31.6%). All individual COPCs, except TMD, were significantly more frequent in females than males. The unadjusted PR (ME/CFS compared to HC) was highest for FM [147.74 (95% confidence interval (CI) = 20.83-1047.75], followed by cLBP [39.45 (12.73-122.27)], and IC/IB [13.78 (1.88-101.24)]. The significance and order did not change after age and sex adjustment. The COPC comorbidities of cLBP and FM each had a significant impact on most health measures, particularly in pain attributes (Cohen’s d effect size 0.8 or larger). While the impact of COPC comorbidities on non-pain attributes and quality of life measures was less pronounced than that on pain, statistically significant differences between ME/CFS participants with and without COPCs were still evident.

Conclusions: More than 75% of ME/CFS participants had one or more COPCs. Multiple COPCs further exacerbated illness severity, especially among females with ME/CFS. Assessment and management of COPCs may help improve the health and quality of life for patients with ME/CFS.

Source: Fall EA, Chen Y, Lin JS, Issa A, Brimmer DJ, Bateman L, Lapp CW, Podell RN, Natelson BH, Kogelnik AM, Klimas NG, Peterson DL, Unger ER; MCAM Study Group. Chronic Overlapping Pain Conditions in people with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS): a sample from the Multi-site Clinical Assessment of ME/CFS (MCAM) study. BMC Neurol. 2024 Oct 18;24(1):399. doi: 10.1186/s12883-024-03872-0. PMID: 39425035; PMCID: PMC11488184. https://pmc.ncbi.nlm.nih.gov/articles/PMC11488184/ (Full text)

Recent Research Trends in Neuroinflammatory and Neurodegenerative Disorders

Abstract:

Neuroinflammatory and neurodegenerative disorders including Alzheimer’s disease (AD), Parkinson’s disease (PD), traumatic brain injury (TBI) and Amyotrophic lateral sclerosis (ALS) are chronic major health disorders. The exact mechanism of the neuroimmune dysfunctions of these disease pathogeneses is currently not clearly understood.

These disorders show dysregulated neuroimmune and inflammatory responses, including activation of neurons, glial cells, and neurovascular unit damage associated with excessive release of proinflammatory cytokines, chemokines, neurotoxic mediators, and infiltration of peripheral immune cells into the brain, as well as entry of inflammatory mediators through damaged neurovascular endothelial cells, blood-brain barrier and tight junction proteins. Activation of glial cells and immune cells leads to the release of many inflammatory and neurotoxic molecules that cause neuroinflammation and neurodegeneration.

Gulf War Illness (GWI) and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) are chronic disorders that are also associated with neuroimmune dysfunctions. Currently, there are no effective disease-modifying therapeutic options available for these diseases. Human induced pluripotent stem cell (iPSC)-derived neurons, astrocytes, microglia, endothelial cells and pericytes are currently used for many disease models for drug discovery. This review highlights certain recent trends in neuroinflammatory responses and iPSC-derived brain cell applications in neuroinflammatory disorders.

Source: Cohen J, Mathew A, Dourvetakis KD, Sanchez-Guerrero E, Pangeni RP, Gurusamy N, Aenlle KK, Ravindran G, Twahir A, Isler D, Sosa-Garcia SR, Llizo A, Bested AC, Theoharides TC, Klimas NG, Kempuraj D. Recent Research Trends in Neuroinflammatory and Neurodegenerative Disorders. Cells. 2024 Mar 14;13(6):511. doi: 10.3390/cells13060511. PMID: 38534355; PMCID: PMC10969521. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10969521/ (Full text)

Heterogeneity in Measures of Illness among Patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Is Not Explained by Clinical Practice: A Study in Seven U.S. Specialty Clinics

Abstract:

Background: One of the goals of the Multi-site Clinical Assessment of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (MCAM) study was to evaluate whether clinicians experienced in diagnosing and caring for patients with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) recognized the same clinical entity.
Methods: We enrolled participants from seven specialty clinics in the United States. We used baseline data (n = 465) on standardized questions measuring general clinical characteristics, functional impairment, post-exertional malaise, fatigue, sleep, neurocognitive/autonomic symptoms, pain, and other symptoms to evaluate whether patient characteristics differed by clinic.
Results: We found few statistically significant and no clinically significant differences between clinics in their patients’ standardized measures of ME/CFS symptoms and function. Strikingly, patients in each clinic sample and overall showed a wide distribution in all scores and measures.
Conclusions: Illness heterogeneity may be an inherent feature of ME/CFS. Presenting research data in scatter plots or histograms will help clarify the challenge. Relying on case–control study designs without subgrouping or stratification of ME/CFS illness characteristics may limit the reproducibility of research findings and could obscure underlying mechanisms.
Source: Unger ER, Lin J-MS, Chen Y, Cornelius ME, Helton B, Issa AN, Bertolli J, Klimas NG, Balbin EG, Bateman L, et al. Heterogeneity in Measures of Illness among Patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Is Not Explained by Clinical Practice: A Study in Seven U.S. Specialty Clinics. Journal of Clinical Medicine. 2024; 13(5):1369. https://doi.org/10.3390/jcm13051369 https://www.mdpi.com/2077-0383/13/5/1369 (Full text)

Low-Dose Naltrexone Improves post-COVID-19 condition Symptoms

Abstract:

Purpose: Treatments for myalgic encephalomyelitis and chronic fatigue syndrome can be adapted for post-COVID-19 condition. Our aim was to compare treatments in patients from our post-COVID-19 clinic.

Methods: We conducted a retrospective cohort study and included consecutive patients enrolled in our post-COVID-19 clinic. We included patients who received low-dose naltrexone, amitriptyline, duloxetine, and physical therapy, and evaluated improvements in fatigue, pain, dyspnea, and brain fog recorded in the electronic health record. We calculated the adjusted relative hazard of improvement using Cox proportional models. We adjusted for demographic characteristics, comorbidities, and prior COVID-19 hospitalization.

Findings: We included the first 108 patients with post-COVID-19 enrolled in the clinic. Most of the patients received amitriptyline. The relative hazard of improvement for those taking low-dose naltrexone was 5.04 (95% CI, 1.22-20.77; P = 0.02) compared with physical therapy alone. Both fatigue and pain were improved in patients taking low-dose naltrexone; only fatigue was improved in patients taking amitriptyline.

Implications: Post-COVID-19 condition symptoms may improve in patients taking medications adapted from myalgic encephalomyelitis and chronic fatigue syndrome. Randomized controlled trials should evaluate these medications and translational studies should further evaluate their mechanisms of action.

Source: Tamariz L, Bast E, Klimas N, Palacio A. Low-Dose Naltrexone Improves post-COVID-19 condition Symptoms. Clin Ther. 2024 Jan 23:S0149-2918(24)00003-1. doi: 10.1016/j.clinthera.2023.12.009. Epub ahead of print. PMID: 38267326. https://pubmed.ncbi.nlm.nih.gov/38267326/

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

Highlights:

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

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

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

Abstract:

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

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

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

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

The potential role of ocular and otolaryngological mucus proteins in myalgic encephalomyelitis/chronic fatigue syndrome

Abstract:

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a debilitating illness associated with a constellation of other symptoms. While the most common symptom is unrelenting fatigue, many individuals also report suffering from rhinitis, dry eyes and a sore throat.

Mucin proteins are responsible for contributing to the formation of mucosal membranes throughout the body. These mucosal pathways contribute to the body’s defense mechanisms involving pathogenic onset. When compromised by pathogens the epithelium releases numerous cytokines and enters a prolonged state of inflammation to eradicate any particular infection.

Based on genetic analysis, and computational theory and modeling we hypothesize that mucin protein dysfunction may contribute to ME/CFS symptoms due to the inability to form adequate mucosal layers throughout the body, especially in the ocular and otolaryngological pathways leading to low grade chronic inflammation and the exacerbation of symptoms.

Source: Huitsing K, Tritsch T, Arias FJC, Collado F, Aenlle KK, Nathason L, Fletcher MA, Klimas NG, Craddock TJA. The potential role of ocular and otolaryngological mucus proteins in myalgic encephalomyelitis/chronic fatigue syndrome. Mol Med. 2024 Jan 3;30(1):1. doi: 10.1186/s10020-023-00766-8. PMID: 38172662. https://molmed.biomedcentral.com/articles/10.1186/s10020-023-00766-8 (Full text)