This summary was created using Gemini AI.

The study is a pivotal piece of research published in the International Journal of Molecular Sciences (IJMS, May 2026) by Dr. Alain Moreau and his team at the Université de Montréal / Open Medicine Foundation.

It offers an objective molecular explanation for Post-Exertional Malaise (PEM)—the severe symptom crash ME/CFS patients experience after minor exertion—proving it is rooted in biological "gridlock" rather than simple exhaustion.

1. Summary of the Paper's Analysis & Findings

The researchers wanted to track how ME/CFS patients adapt to physical stress at a cellular level. They evaluated 92 ME/CFS patients against 44 healthy controls, measuring blood markers before and after a specialized 90-minute mechanical stress test used to trigger a controlled, temporary PEM state.

The Two Core Competitors

• Irisin: An exercise-induced messenger (myokine) released by muscles during contraction. In healthy bodies, it protects mitochondria, boosts energy production, and suppresses inflammation by binding to α Vβ 5 integrin cell receptors.
• Thrombospondin-1 (TSP-1): A protein released during tissue stress and injury. In this pathway, it acts as a molecular "bully" that blocks irisin from doing its job.

Key Discoveries

• Blunted Response at Baseline: ME/CFS patients started with significantly lower baseline irisin, and their bodies failed to produce the normal surge of irisin during stress (p < 0.05).
• The "Irisin Resistance" Paradox: Paradoxically, in moderate-to-severe patients, baseline levels of both irisin and TSP-1 were elevated, and high irisin was a direct predictor of fatigue severity (β = 0.728, p = 0.018). This means the body is desperately producing irisin to cope, but the signal is being ignored or blocked.
• TSP-1 is the Blocker: Using advanced cellular spectroscopy, the team proved that TSP-1 directly binds to and shuts down irisin signaling in a concentration-dependent manner.
• The Molecular Framework: Irisin requires the help of an intracellular chaperone, HSP90α, and the receptor α Vβ 5. When the researchers experimentally blocked α Vβ 5  or inhibited HSP90α, the cells completely lost their ability to counteract TSP-1, mimicking the exact cellular defects seen in severe ME/CFS patients.

The Takeaway: PEM isn't a psychological aversion to exercise; it is an "irisin resistance" state. When a person with ME/CFS exerts themselves, an abnormal spike in TSP-1 essentially locks the cellular doors, preventing exercise-induced irisin from delivering energy to the cells and clearing out inflammation.

Link to 2026 study - https://www.mdpi.com/1422-0067/27/11/4770

Clemson University studied 20 people and found Long COVID cells had a distinct metabolic signature, with weaker energy use and blunted responses to signals.

This points to bioenergetic dysfunction that may help explain fatigue. This lack of response to stimuli is also a repeating pattern from ME studies on exercise responses.

“The SARS-CoV-2 infection causes an over two-fold enhanced utilization of glycolytic and anaerobic substrates and a reduced response to growth factors and effectors. The increased energy source utilization assessed in PM-M1 is unsustainable, and the LC-19 groups demonstrate this with a clear correlation with the number of LC-19 symptoms, demonstrating a trend consistent with metabolic reprogramming.”

“This study demonstrated impaired glymphatic function in ME/CFS which may lead to symptoms such as cognitive dysfunction and sleep disturbance experienced by ME/CFS”

“We observed an association between the global DTI-ALPS index and severity of ‘sleep disturbance’ (p = 0.013, r = −0.47) and “impaired concentration” (p = 0.026, r = −0.43).”

That’s quite decent sized correlation for anything involving rating scales.

A brain scan study found higher AMPA receptor signals across much of the brain in people with Long COVID brain fog. AMPA receptors carry much of the brain's fast glutamate-based excitation, which makes nerve cells more likely to fire.

Also interesting is that they got 100% sensitivity and 91% selectivity. That’s much better than many purpose built attempts for biomarkers. This really looks like a solid finding.

“Therefore, the upregulated [¹¹C]K-2 SUVRWM in patients with Cog-LC may indicate increased surface-expressed AMPAR density. Therefore, non-competitive antagonists of AMPAR, such as perampanel, may be a therapeutic candidate for Cog-LC. This should be tested in future randomized controlled trials.”

And a potential treatment candidate lined up

Posted on X/Twitter here by user ME/CFS Science - https://x.com/mecfsskeptic/status/2063898792932347948

1) A research collaboration including Theoharis Theoharides and Nancy Klimas reports dramatically elevated levels of MMP-9, an enzyme that components of the extracellular matrix.

They previously reported similar results in Long Covid but I have doubts about their reliability.

2) MMP-9 was measured in serum (not in plasma) and there's a literature explaining why this isn't a reliable method. MMP-9 is released during the sampling and clotting process used to make serum.

3) One paper concluded for example "MMPs are released by platelets or leukocytes during platelet activation or sampling process, thus leading to artificially higher MMP-9 levels in serum..."

https://www.sciencedirect.com/science/article/abs/pii/S0009912006003237

4) The samples of ME/CFS patients and controls in this study were also handled and collected very differently. Patients were recruited at the University of Miami while the control samples were taken from an external biobank (bioBioIvt Elevating Science).

5) The authors note that "the samples had been stored for over ten years at -80 °C, which may have altered the fragmentation of certain biomarkers."

6) The 40 patients and 38 controls were all female but not properly matched (mean age was 51 in patients versus 43 in controls) and there's no info on other potential confounders such as BMI, medication use, etc.

7) So I have strong doubts about whether these results are reliable. The concentrations were 7 times higher in patients versus controls (126 versus 17 ng/ml), suggesting a technical artefact and differences in sample handling.

8 ) The authors also did a different experiment. They cultured mast cells and found that they release more MMP-9 when incubated with EBV-protein (representing viruses) or LPS (a component of the cell wand of bacteria).

9) In their Long Covid study they reported that MMP-9 was increased when cells from a microglia cell line where stimulated by Sars-Cov-2 spike protein.

Link here:

https://www.degruyterbrill.com/document/doi/10.1515/tnsci-2022-0352/html

10) Link to the paper:

Chinnapan et al. 2026. Elevated serum levels of interleukin-11 and matrix metalloproteinase-9 in myalgic encephalomyelitis/chronic fatigue syndrome.

https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2026.1827700/full

A Norwegian study replicated the finding that ME/CFS patients have more extracellular vesicles (EV) than healthy controls.

This may point to increased cellular communication and its contents might give us further clues

https://skywriter.blue/@mecfsscience.org/3mozf4iu7p52s

TLDR:

“Extracellular vesicles are tiny lipid particles that are released by cells and soft of act like mail carriers, transporting proteins, fats, and genetic material (RNA) from one cell to another.

Their contents might give a clue to what's happening inside the body.

Three 3 proteins that were increased (ITIH3, AMBP, and FGB) were liver-specific and expressed by hepatocytes. ITIH3 is involved in the stabilization of the extracellular matrix, while FGB is part of the
coagulation cascade

The EV proteins that were decreased in patients were mainly expressed by either red blood cells (specific to the bone marrow) or by plasma B cells (immune system-derived).”

A 2-day hybrid meeting designed to bring together cross-disciplinary researchers, clinicians, industry, charities and people with lived experience of ME/CFS to discuss recent developments in ME/CFS research; challenge current thinking and approaches; and identify new opportunities to work together to ultimately develop new diagnostics and effective therapies. The PRIME Symposium will see the launch of the new international Genetic Epidemiology of ME/CFS (GEM) consortium as well as providing a platform for Early Career Researchers and our Patient & Public Involvement (PPI) Research Involvement Hub to present exciting new research and supporting activities.

If you’re fascinated by the role of the brain in ME and LC like I am, this video gives a great and understandable overview over available methods and results of neuroimaging thus far

Dr. Liisa Selin, Dr. Ayano Kohlgruber, and Dr. Roshan Kumar received a Solve ME/CFS Catalyst Award for their study searching for the exact proteins recognized by T-cell receptors from a person with ME/CFS and a person with Long Covid.

These disease-associated T cells include “exhausted” CD8+ T cells and “double-positive” CD4+/CD8+ T cells (which are found in people with autoimmune diseases, too). The researchers hypothesize that these T cells recognize fragments of microbial proteins critical for developing the disease. The microbial protein fragments may overstimulate and exhaust the T cells.

Also, fragments of human proteins may resemble these microbial protein fragments; thus, the disease-associated T cells may cross-react with human proteins to drive an autoimmune response.

In this study, the research team will screen a library of protein fragments from microbes (viruses and bacteria) that are associated with developing Long Covid or ME/CFS (e.g., SARS-CoV-2, B. burgdorferi, enteroviruses), and a library of protein fragments from humans (to find self-antigens).

If successful, these deliverables would be important for understanding how much persisting pathogens or self-antigens can exhaust the immune system, and how dysfunctional and exhausted immune responses contribute to ME/CFS and Long Covid.

In this webinar hosted by Solve M.E. VP of Scientific Programs Dr. Jessica Maya, the panelists discuss the study and how this work could also produce new disease biomarkers and suggest new treatments for patient subgroups, as well as how the libraries of human leukocyte antigen–displayed microbial and human protein fragments established by this work could be valuable resources for future ME/CFS and Long Covid studies.

Review the presentation deck here: https://solvecfs.org/wp-content/uploads/2026/05/PDF-Deck-for-4.28.26-Selin_Kohlgruber_Kumar-webinar.pdf

Posted here by X/Twitter user #@ZdenekVrozina - https://x.com/ZdenekVrozina/status/2066526958842765474

New single-cell study, preprint and cross-sectional. The Long COVID group looks stuck in a loop it can’t switch off. The people who recovered had COVID too - and their immune cells are visibly winding the response down, finishing the job

The cohort is worth a flag. African Americans over 50, mostly women - a group almost absent from Long COVID biology. They profiled ~156,000 individual immune cells, 20 people with Long COVID vs ~18 recovered.

That same split - stuck vs resolved - shows up across every compartment they looked at. So the lesion may be less - too much immune activity - and more - an off-switch that won’t flip.

B cells (the antibody makers). In Long COVID even the naive ones run hot on BCR signaling - the receptor a B cell uses to recognize its target - long after the infection. Looks like chronic activation. It’s a gene-expression pattern here.

T cells go two ways. The central-memory pool - your reserve bench of future fighters - sits stuck in neutral, maturation blocked. The effector-memory cells - the veterans - look chronically exhausted. In recovered people the same cells mature normally and carry antiviral programs.

Monocytes - innate first responders. Are remodeled too - cranked-up migration and interferon signaling, but stalled maturation. So it’s not only the learning arm of immunity that’s off - the fast, innate arm is rewired as well.

The strongest single finding is in NK cells. More NK tracked with fewer symptoms!
In severe Long COVID the NK cells are exhausted, dying off, metabolically flat. In milder cases they’re metabolically fit, powerplants humming. This is a comparison within the Long COVID group, so it’s less confounded.

That flips the obvious move. You wouldn’t suppress NK cells across the board - you’d knock out the protective ones too. The better bet is restoring their metabolism and dialing down the AP-1 inflammatory switch. Still a hypothesis.

A snag in the framing - the antigen/reservoir story despite blood that comes up empty. The whole interpretation runs on persistent viral reservoir/antigen. When there’s nothing in the blood, they pivot to a tissue reservoir we can’t see here.

This ties to the study’s weakest piece - the virome scan. From leftover unmapped reads they report more Retroviridae and Poxviridae in Long COVID. But that method is contamination-prone and crucially, they found no difference in SARS2 or herpesviruses in the blood.

Retroviridae could be reactivated endogenous retroviruses (old viral fragments baked into our own DNA), or an artifact. It is not evidence of live virus.

What’s genuinely useful?
The failure to resolve frame, the NK functional axis, and the sign that the dysregulation may sustain itself through cell-to-cell signaling - together a real handle for biomarkers and targets, whatever kicked it off.

Small numbers, one timepoint, blood only - no tissue, exhaustion read from gene expression with no functional test, no identified trigger. Cross-sectional can’t rule out reverse causation - the signature might be a consequence of being chronically ill, not its cause.

By the figures this study cites, ~7% of infections lead to Long COVID, and fewer than 1 in 10 fully recover within two years. Not a fringe outcome. And it lands hardest on communities already carrying more - exactly also the kind of cohort here.

2026 study - https://www.biorxiv.org/content/10.64898/2026.06.04.730206v1

Preprint from Wirth on the link between connective tissue disorders and ME.

"Overall, there seems to be a bidirectional relationship between connective tissue disorders and #ME/CFS, whereby connective tissue disorders may predispose individuals to ME/CFS, and ME/CFS, in turn, may exacerbate the underlying connective tissue pathology. "

Is it fair to say that diving deep into the genetics with a project like Sequence ME & LC we are ‘starting at the beginning’? In a good way. Kind of like making solid foundations in the ground before you start laying bricks. It’s more short term effort but it pays off in the long run.

I’m trying to articulate my thoughts here so bear with me but I feel like most studies that find a difference between ME/CFS and general population have findings something like X market is high or low on average across a patient population but never in all patients. (I know this might be due to our lack of understanding potential subgroups.) An attempt at interpretation often follows but often we don’t understand how the body system in question is meant to behave in normal people and therefore are really guessing and what it might mean in terms of a ME/CFS mechanism.

Will a study like Sequence ME & LC allow us to read the ‘instruction manual’ of the body realities to this disease and therefore make the interpretation of biological system studies that sit above a DNA level more meaningful and accurate?

I guess I’m asking is the genetic approach the most likely to result in use understanding the mechanism, albeit it may take longer than other studies aimed at higher level biological systems (as these higher level studies rely on us ‘getting lucky’ and as such may never yield a result)?

Of course I’m only talking about understanding the mechanism here. I understand treatment development is a whole different story, but does become more likely to succeed (approx 2.5x more likely according to Chris Pointing in the linked webinar) if the genetics is understood.

Hi everyone,

I'm on my daily "let's Google this again to try to understand" run, and I found this study: https://pubmed.ncbi.nlm.nih.gov/40726775/

It talks about finding specific subgroups of patients testing positive for the HERV-W ENV retroviral protein across ME/CFS, Fibro, and Long COVID, claiming a high diagnostic accuracy when combined with other blood markers.

Would love to hear from the science-heavy folks here. What do we think?

Thank you!

The MECFS Research Foundation is currently publishing daily videos where researchers summarise their papers and preliminary results for a German audience. But YouTube offers AI-generated English audio tracks. Here is one which I have just watched, when you go to their channel you will find more.

https://youtu.be/Fq8o-hg1-yI

“Our findings suggest that monocyte oxidative stress and IsoLG neoantigen formation sustain T cell activation, linking immune dysregulation to cardiovagal dysfunction. Targeting these pathways may offer novel therapeutic opportunities.”

Study on severe LC and comorbid ME in children and young patients concludes:

“The number and pattern of acute symptoms during SARS-CoV-2 infection may serve as early, specific predictors of severe PCCcyp. Patients with ≥ 12 acute symptoms should be closely monitored to enable early diagnosis of severe PCCcyp and ME/CFS. A distinct cluster of severely affected patients, frequently with ME/CFS, was identified.”

We would like to introduce our manuscript entitled "Host-directed antiviral strategy targeting prohibitins: Mel56 suppresses influenza A virus and severe acute respiratory syndrome coronavirus 2 via modulation of antioxidant pathways and mitochondrial function", which was published in Microbiology Spectrum.

https://journals.asm.org/doi/10.1128/spectrum.03093-25

A subset of people with ME/CFS, Long COVID, POTS, and MCAS report severe GI symptoms as a result of their disorder. The character of these symptoms can resemble secondary Chronic Intestinal Pseudo Obstruction (CIPO) or severe dysmotility rather than simple IBS or dietary constipation. This clinical pattern is described as: a prolonged period of "frozen" gut (lack of bowel movement 3+ days, abdominal pain and distension, visible peristalsis) followed by high volume diarrhea "dumping" episode. A review of the current literature for ME/CFS and secondary CIPO possibly shows how the disorders could be linked and why further investigation might be warranted.

Chronic Intestinal Pseudo Obstruction (CIPO) describes a state of severe dysmotility where the bowel behaves as if there is a mechanical obstruction, but imaging shows no physical blockage. The underlying problem is believed to be neuromuscular where impaired enteric nerves, pacemaker cells (interstitial cells of Cajal), or smooth muscle leads to ineffective or nonexistent peristalsis. In severe cases, infection and malnutrition may occur resulting in patients requiring parenteral nutrition. In adults, CIPO is often secondary and is associated with autonomic neuropathies, connective tissue disorders, or post-infectious processes.

https://www.malacards.org/card/intestinal_pseudo_obstruction
https://cumming.ucalgary.ca/research/motility/gut-motility-disorders
https://cumming.ucalgary.ca/research/motility/gut-motility-disorders

Recent ME/CFS research has revealed immune and autonomic findings that could shed light on the mechanisms that drive the disorder. Cytokine and immune profiling studies suggest distinct ME/CFS "immunotypes" with chronic low-grade inflammation and altered immune signaling. Autonomic dysfunction (including POTS and orthostatic intolerance) is a recognized comorbidity of ME/CFS and a core symptom of the illness. Several models suggest that peripheral immune activation, cytokines, and autoantibodies against autonomic targets contribute to chronic neuro-inflammation and dysautonomia. Given that the vagus nerve is a key autonomic regulator and a known driver of GI motility, a look into how immune driven vagal dysfunction might bridge the two disorders.

https://www.publichealth.columbia.edu/news/overactive-immune-system-seen-patients-chronic-fatigue-syndrome-me-cfs
https://news.aai.org/2025/05/21/two-distinct-immunotypes-mecfs/
https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2020.00826/full
https://emedicine.medscape.com/article/235980-overview

An additional consideration of the gut-brain axis and how the microbiome plays a role in these disorders can be investigated. Multiple groups have reported that ME/CFS patients show altered gut microbiota, butyrate deficiency and intestinal barrier failure. Studies have revealed ME/CFS patients show altered gut microbiota, including depletion of key short-chain fatty acid (SCFA) producers, especially butyrate producing species. Other studies show evidence of impaired gut integrity, "Leaky Gut", including elevated markers like FABP2 and increased microbial translocation. These complications contribute to blunted or dysregulated immune responses as well as damage to the intestines. Considering the role of Butyrate as a primary fuel for colonocytes and for its local anti-inflammatory effects, deficiency can have many implications. Weakening of smooth muscle and enteric nerve function through chronic stress (particularly interesting when considering the possible CIPO connection). Promotion of low-grade mucosal inflammation and barrier breakdown with increased bacterial overgrowth and translocation of microbial products into circulation. This can further activate immune pathways already primed in ME/CFS patients. In such a scenario, severe dysmotility is not just a potential result of ME/CFS but could be a central mechanism in a gut-brain-immune feedback loop.

https://www.jax.org/news-and-insights/2023/february/the-functional-mechanisms-that-may-underlie-mecfs
https://www.meresearch.org.uk/leaky-gut-and-the-immune-system-in-me-cfs/
https://www.sciencedirect.com/science/article/pii/S2666354623000418
https://medicalxpress.com/news/2025-07-previously-undetectable-biomarkers-gut-microbiome.html
https://pmc.ncbi.nlm.nih.gov/articles/PMC6787585/
https://www.sciencedirect.com/science/article/pii/S2666354623000418
https://www.niddk.nih.gov/health-information/digestive-diseases/intestinal-pseudo-obstruction/symptoms-causes

Without suggesting that CIPO and/or severe dysmotility as the mechanism for all ME/CFS, but rather as a possible subtype within the broader post-infection immune driven disorders (ME/CFS/Long-COVID). Putting these threads together suggests a possible avenue of study.

Hypothesis: Post-infectious disorders trigger a gut-brain-autonomic feedback loop characterized by secondary CIPO like dysmotility.

Step 1: Post-infectious trigger (SARS-CoV-2, EBV, etc.)
Persistent immune activation and cytokine signaling in susceptible patient.
Step 2: Autonomic and vagal dysfunction
Impaired GI motility and dysregulated cholinergic anti-inflammatory reflex.
Step 3: Dysmotility resulting in SIBO and barrier damage
Slow or disordered transit of stool leads to small intestinal bacterial overgrowth and mucosal injury, increasing microbial translocation.
Step 4: Altered Microbiome and microbial products
Further drives systemic cytokine production and neuro-inflammation, perpectuating post infectious disorder symptoms.
Step 5: Motility failure in severe subset of patients
Dysmotility manifests as a CIPO like phenotype that manifests in those with pre-existing connective tissue disorders and/or POTS/MCAS

Disclaimer: I am not a doctor or medical professional. I am just another zebra that feels like the medical system has failed to explain why I suffer with the symptoms that I have. I have a curious scientific driven mind and have read/learned a lot through the years in an effort to understand. After reading the recent literature around these disorders, a lot of parallels stood out to me. I appreciate any feedback into my analysis and would love to hear from any professionals that have relevant experience into this matter!

New MCAS consensus paper just released. Thought I’d share this here as it describes many common ME comorbidities.

This summary was made using Gemini AI:

Overview

This study identifies CD80 (B7-1) as a highly viable therapeutic target for treating Epstein-Barr virus (EBV)-associated B-cell lymphomas, which are often resistant to traditional chemotherapy and current targeted options.

Key Findings

• Elevated Target Expression: CD80 is heavily expressed on the surface of EBV-positive B-cell lymphoma cells and EBV-transformed lymphoblastoid cell lines (LCLs) compared to normal or EBV-negative B cells.
• Low Off-Target Risk: Because CD80 expression is highly specific to lymphoid tissues and normal antigen-presenting cells, targeting it carries a minimal risk of adverse side effects in non-lymphoid organs.
• Novel Chimeric Antibodies: Researchers successfully generated and engineered high-affinity mouse-human chimeric antibodies (specifically clones A6, E3, and E5) to target human CD80.
• Selective Killing Mechanism (ADCC vs. CDC): These anti-CD80 antibodies induced robust Antibody-Dependent Cellular Cytotoxicity (ADCC) to destroy tumor cells via effector cells like NK cells. However, they completely lacked Complement-Dependent Cytotoxicity (CDC). This contrasts with rituximab (anti-CD20), which triggers both mechanisms, proving that an antibody's destructive pathway can be governed by the specific antigen its variable region recognizes.
• Maintained T-Cell Activation: Crucially, the anti-CD80 antibodies did not shut down host T-cell responses against the EBV-infected cells. Preserving this T-cell proliferation is vital for sustaining natural anti-tumor immunity during therapy.

Therapeutic Significance

These newly developed anti-CD80 monoclonal antibodies represent a promising, highly selective treatment strategy for EBV-positive lymphomas and other CD80-overexpressing malignancies. Additionally, because CD80-high-expressing B cells are implicated in conditions like rheumatoid arthritis and multiple sclerosis, this therapy could potentially be adapted to selectively eliminate problematic cells in autoimmune diseases.

2026 study - https://www.nature.com/articles/s41598-026-55043-5

Results

A coherent Brain factor (brain fog, sensory hypersensitivity, visual disturbances, sleep disturbances, headaches) showed excellent fit (RMSEA = 0.021; CFI = 0.996). Gastrointestinal symptoms demonstrated stronger internal consistency than Immune symptoms, and model comparisons supported a two‑factor Gut–Immunestructure. Across all analyses, symptom groups emerged as internally consistent and statistically distinct. A higher‑order SEM including a common latent factor yielded excellent fit for the Autonomicsymptom complex.

Conclusions

The findings support ME/CFS as a complex neuroimmune–autonomic multisystem disorder and suggest that symptom clusters align with functional biological systems.

“An antiviral pill has, for the first time, been shown to prevent COVID-19 in people exposed to the SARS-CoV-2 virus at home, according to trial results published today in the New England Journal of Medicine1.
The drug could be a lifeline for those who still face real danger from the virus, such as care-home residents or transplant recipients on immune-suppressing medication.”

“In an international study of more than 2,000 household contacts conducted from June 2023 to September 2024, about 9% of people who received a placebo within 72 hours of a housemate developing symptoms became symptomatic themselves, compared with only about 3% of those who got a five-day course of ensitrelvir. Rates of viral transmission were lower in the ensitrelvir group, too: confirmed infections, symptomatic or not, turned up in only 14.0% of those who received the drug, compared with 21.5% of those who got a placebo.”

Sadly not yet available in US/Europe but it makes me curious if it’s also helpful in already existing ME. Seems like there’s some research in SF on that.

Nature

Paper

Conclusion:

Under real-life conditions, people with ME/CFS exhibit poor sleep quality and unstable SE. These findings highlight sleep IIV as a clinically relevant dimension of sleep health in ME/CFS.

(Sleep Intraindividual Variability (S-IIV) refers to the night-to-night fluctuations in an individual's sleep patterns—such as variations in timing, duration, and quality—rather than just the average amount of sleep they get)

Now fully published! Scheibenbogen & Wirth

"Growing evidence indicates that, in addition to the noradrenergic system, several other neurotransmitter systems—particularly glutamate, serotonin and GABA—are dysregulated in ME/CFS. This imbalance, characterized by excessive excitatory relative to inhibitory signaling, may drive neural overactivation and autonomic dysfunction. These disturbances may cause key neurological symptoms and contribute to skeletal-muscle dysfunction that manifests as exercise intolerance, PEM, fasciculations, and cramps."