Skip to content

Start Here
Atlas
Evidence
Research
Ask
Updates
About
Support

Evidence Atlas

ME/CFS Atlas — A public knowledge atlas for ME/CFS

Start Here
Atlas
Evidence
Research
Ask
FAQ
Glossary
Updates
Methodology
Press
Retractions
Contribute
About
Support
Contact

Weekly research digest — no spam

ME/CFS Atlas is an evidence reference platform, not a medical provider. Content is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional.

Generator v1·Scanner v1.4·Lint gate: enforce·See methodology

© 2026 ME/CFS Atlas

ME/CFS Evidence Browser — Classified Studies on Myalgic Encephalomyelitis

Evidence browser

Search and filter 6,206 studies by evidence level, diagnostic criteria, PEM status, and research domain. Each entry links to the original source.

Studies sorted by evidence level, then year. Browse by topic instead →

Evidence level (E0–E3) reflects study type and replication, not methodological quality. A weak systematic review still sits at E0. How evidence levels work →

Sort

1205 studies

E0 — Consensus655E1 — Replicated321E2 — Moderate2,807E3 — Preliminary2,423

ME/CFS4,041Long COVID224Post-infectious190Overlapping1,064

Required for diagnosis417Not specified / unclear2,252Not required3,537

Post-Exertional Malaise1,082Cognitive Dysfunction1,750Pain1,629Unrefreshing Sleep805Orthostatic Intolerance484

Cytokines821Gene Expression573Metabolomics478Neuroimaging472Autoantibodies460

Infection-Triggered1,182Long COVID Overlap604Pediatric496Severe232

Strong Phenotyping445Sex-Stratified330Severe ME Included119

Systematic Review272Meta-Analysis61RCT301

Peer-reviewed6,149Preprint3Unclear54

1061–1080 of 1,205 studies

E3 PreliminaryReviewPEM unclearReview-Narrative

[Use of IVIG in secondary immunodeficiencies].

Zeman, Krzysztof, Lewandowicz-Uszyńska, Aleksandra·Postepy higieny i medycyny doswiadczalnej·2002

This review article examines whether intravenous immunoglobulin (IVIG)—a blood product containing antibodies—might help patients with weakened immune systems, including those with HIV and chronic fatigue syndrome. The authors looked at published research to understand when and how IVIG might be useful, particularly for people recovering from serious injuries, burns, or major surgery.

E3 PreliminaryReviewPEM unclearReview-Narrative

Evidence for the presence of immune dysfunction in chronic fatigue syndrome.

Natelson, Benjamin H, Haghighi, Mohammad H, Ponzio, Nicholas M·Clinical and diagnostic laboratory immunology·2002

This review article examines whether people with ME/CFS have problems with their immune system. The researchers looked at evidence from multiple studies and found signs that the immune system may not be working normally in people with this condition. This helps explain why ME/CFS causes such severe fatigue and other symptoms.

E3 PreliminaryMechanismPEM not requiredMechanistic

A computational analysis of Canale-Smith syndrome: chronic lymphadenopathy simulating malignant lymphoma.

Krueger, Gerhard R F, Brandt, Michael E, Wang, Guanyu et al.·Anticancer research·2002

Researchers used a computer model to simulate how the immune system changes when infected with a virus called HHV-6. They found that a chronic (long-lasting) simulated infection produced immune cell patterns similar to what is seen in ME/CFS patients, suggesting that persistent viral infection might be connected to the disease.

E3 PreliminaryReviewPEM not requiredReview-Narrative

Theoretical accounts of Gulf War Syndrome: from environmental toxins to psychoneuroimmunology and neurodegeneration.

Ferguson, E, Cassaday, H J·Behavioural neurology·2002

This paper suggests that the confusing mix of symptoms seen in Gulf War Syndrome and chronic fatigue syndrome may actually be one condition caused by inflammation in the body rather than separate diseases. The authors propose that inflammatory molecules called cytokines trigger a 'sickness response' similar to what happens when you have the flu, and that smells or other reminders from the environment can keep this sickness response going long after it should have stopped.

E3 PreliminaryMechanismPEM not requiredCase-Control

Using an interleukin-6 challenge to evaluate neuropsychological performance in chronic fatigue syndrome.

Arnold, M C, Papanicolaou, D A, O'Grady, J A et al.·Psychological medicine·2002

Researchers gave ME/CFS patients and healthy people a substance called interleukin-6 to temporarily trigger flu-like symptoms. They then tested how well both groups could think and remember during this induced illness. ME/CFS patients reported more overall sickness symptoms, but surprisingly, both groups performed equally well on memory and thinking tests, suggesting that the temporary immune activation didn't impair cognitive abilities in either group.

E3 PreliminaryReviewPEM not requiredReview-Narrative

Connecting cytokines and brain: a review of current issues.

Quan, N, Herkenham, M·Histology and histopathology·2002

This review examines how immune molecules called cytokines communicate with the brain and affect how it works. Scientists have found that cytokines can trigger fatigue, changes in mood and behavior, and problems with the nervous system. The authors suggest that cytokines may play a role in several brain-related conditions, including chronic fatigue syndrome.

NeuroinflammationImmune System

E3 PreliminaryCohortPEM unclearCase-Control

Peripheral blood mononuclear cell beta-endorphin concentration is decreased in chronic fatigue syndrome and fibromyalgia but not in depression: preliminary report.

Panerai, Alberto E, Vecchiet, Jacopo, Panzeri, Paolo et al.·The Clinical journal of pain·2002

This study measured a natural pain-relieving substance called beta-endorphin in immune cells from people with ME/CFS, fibromyalgia, depression, and healthy controls. The researchers found that people with ME/CFS and fibromyalgia had significantly lower levels of beta-endorphin than healthy people and those with depression. This suggests the immune systems of people with ME/CFS and fibromyalgia may be working differently than in other conditions.

E3 PreliminaryReviewPEM not requiredReview-Narrative

Cytokine responses to physical activity, with particular reference to IL-6: sources, actions, and clinical implications.

Shephard, Roy J·Critical reviews in immunology·2002

When people exercise, their muscles release a protein called IL-6 that helps control inflammation and manage energy. This review examines how the body produces different types of inflammatory signals during and after exercise, with IL-6 playing a central role. The authors note that people with ME/CFS have higher levels of these inflammatory proteins, though it's unclear whether these proteins actually cause the fatigue experienced by patients.

Immune SystemPost-Exertional Malaise

E3 PreliminaryCohortPEM not requiredLongitudinal

Dynamics of chronic active herpesvirus-6 infection in patients with chronic fatigue syndrome: data acquisition for computer modeling.

Krueger, G R, Koch, B, Hoffmann, A et al.·In vivo (Athens, Greece)·2001

This study followed 10 ME/CFS patients for two years to understand how a virus called HHV-6 might be involved in their illness. Researchers measured virus levels and immune cell counts in the patients' blood over time. They found that ME/CFS patients had slightly elevated virus levels and abnormal immune responses, different from what happens during acute HHV-6 infection.

E3 PreliminaryMechanismPEM not requiredMechanistic

Detection of immunologically significant factors for chronic fatigue syndrome using neural-network classifiers.

Hanson, S J, Gause, W, Natelson, B·Clinical and diagnostic laboratory immunology·2001

Researchers used advanced computer analysis to find immune system differences in ME/CFS patients that traditional statistical methods had missed. They discovered that ME/CFS patients have lower levels of certain immune cells and higher levels of a chemical messenger called interleukin-4, suggesting their immune system may be stuck in a particular type of response pattern.

E3 PreliminaryReviewPEM unclearReview-Narrative

Elevated nitric oxide/peroxynitrite mechanism for the common etiology of multiple chemical sensitivity, chronic fatigue syndrome, and posttraumatic stress disorder.

Pall, M L, Satterlee, J D·Annals of the New York Academy of Sciences·2001

This theory paper proposes that ME/CFS, multiple chemical sensitivity (MCS), and post-traumatic stress disorder may share a common cause: abnormally high levels of nitric oxide and related harmful molecules in the body. The authors suggest that feedback loops—where one problem triggers another, which makes the first worse—could explain why these conditions become chronic and persist over time.

E3 PreliminaryReviewPEM unclearReview-Narrative

Cytokines and chronic fatigue syndrome.

Patarca, R·Annals of the New York Academy of Sciences·2001

This study found that people with ME/CFS show signs of immune system activation (more active immune cells and elevated immune signaling molecules), yet paradoxically have weak immune function (poor natural killer cell activity and weak responses to infections). The immune system appears to be stuck in an imbalanced state, favoring certain types of inflammatory responses, which may relate to symptom cycles of improvement and worsening.

E3 PreliminaryReviewPEM unclearReview-Narrative

DHEA. Monograph.

Alternative medicine review : a journal of clinical therapeutic·2001

This article reviews DHEA, a hormone naturally produced by your body that decreases as you age. Research suggests that lower DHEA levels may be connected to several conditions, including ME/CFS, heart disease, diabetes, and autoimmune diseases like lupus and rheumatoid arthritis. DHEA acts as a 'buffer hormone' that can be converted into other important hormones like estrogen and testosterone.

E3 PreliminaryMechanismPEM not requiredMechanistic

Increased sensitivity to glucocorticoids in peripheral blood mononuclear cells of chronic fatigue syndrome patients, without evidence for altered density or affinity of glucocorticoid receptors.

Visser, J, Lentjes, E, Haspels, I et al.·Journal of investigative medicine : the official publication of the American Federation for Clinical Research·2001

Researchers found that immune cells from ME/CFS patients react more strongly to a stress hormone called dexamethasone (a type of glucocorticoid) than cells from healthy people. However, the cells have the same number of receptors for this hormone and bind it with the same strength, suggesting the heightened sensitivity comes from something happening inside the cells after the hormone attaches, rather than from problems with the receptors themselves.

E3 PreliminaryCohortPEM unclearCase-Control

Chronic fatigue syndrome following a toxic exposure.

Racciatti, D, Vecchiet, J, Ceccomancini, A et al.·The Science of the total environment·2001

This study looked at five people who developed ME/CFS symptoms after being exposed to toxic substances—either through seafood poisoning or chemical fumes. Researchers compared them to people with ME/CFS that started after viral infections or depression to see if the cause mattered. They found that people whose ME/CFS followed toxic exposure had more significant problems with immune system function than the comparison groups.

E3 PreliminaryMechanismPEM unclearCross-Sectional

Delayed-type hypersensitivity and chronic fatigue syndrome: the usefulness of assessing T-cell activation by flow cytometry--preliminary study.

Brunet, J L, Liaudet, A P, Later, R et al.·Allergie et immunologie·2001

This small study looked at whether people with ME/CFS have exaggerated immune reactions to common substances like yeast (Candida). Researchers tested this by applying yeast extract under the skin and watching for delayed reactions, then measuring immune cell activity in blood samples. About half of the ME/CFS patients showed these exaggerated reactions, suggesting the immune system may be responding unusually to everyday germs.

E3 PreliminaryReviewPEM not requiredReview-Narrative

Mediators of inflammation and their interaction with sleep: relevance for chronic fatigue syndrome and related conditions.

Mullington, J M, Hinze-Selch, D, Pollmächer, T·Annals of the New York Academy of Sciences·2001

This study explores how the body's immune system and sleep are connected, and how this connection might explain the severe fatigue in ME/CFS. Researchers found that when the immune system is activated, it releases chemical messengers called cytokines that can affect sleep quality and cause fatigue. The study suggests that abnormal levels of these immune chemicals in ME/CFS patients could be responsible for the debilitating tiredness that characterizes the condition.

E3 PreliminaryReviewPEM not requiredReview-Narrative

Anti-nuclear envelope antibodies: Clinical associations.

Nesher, G, Margalit, R, Ashkenazi, Y J·Seminars in arthritis and rheumatism·2001

This study looked at antibodies (immune proteins) that attack the nuclear envelope, the protective membrane around cell nuclei. Researchers found that different types of these antibodies are associated with different diseases, and preliminary findings suggest they may help diagnose ME/CFS. The study suggests that testing for these antibodies could help doctors identify certain autoimmune conditions.

E3 PreliminaryReviewPEM not requiredReview-Narrative

Cytokine and other immunologic markers in chronic fatigue syndrome and their relation to neuropsychological factors.

Patarca-Montero, R, Antoni, M, Fletcher, M A et al.·Applied neuropsychology·2001

This study looked at immune system markers in ME/CFS patients and found that their immune cells show signs of being overactive, with abnormal patterns of immune signaling molecules called cytokines. The researchers propose that when stress and difficult emotions interact with this immune dysfunction, they can perpetuate the cycle of fatigue, cognitive problems, and other symptoms seen in ME/CFS.

E3 PreliminaryCommentaryPEM not requiredEditorial

Altered glucocorticoid regulation of the immune response in the chronic fatigue syndrome.

Visser, J T, De Kloet, E R, Nagelkerken, L·Annals of the New York Academy of Sciences·2000

This study explores how stress hormones called glucocorticoids affect the immune system in ME/CFS patients. The researchers found evidence suggesting that in ME/CFS, these stress hormones may be shifting the immune system's balance in an unhelpful way—boosting certain types of immune responses while weakening others. This could help explain why ME/CFS patients experience ongoing immune system problems.

← Previous Next 20 studies →

Or browse by topic

PEM Immune Neuro Metabolic Biomarkers Severe ME Long COVID Cognitive

Curated Collections

Thematic groupings by clinical question or research area.

Neuroinflammation Evidence

PET imaging and other studies providing evidence for brain inflammation in ME/CFS.

Metabolism & Mitochondria

Metabolomics and mitochondrial function studies revealing energy metabolism disruption.

Biomarkers

Studies identifying potential biological markers for ME/CFS diagnosis and stratification.

PEM-Specific Research

Studies specifically examining post-exertional malaise, the hallmark symptom of ME/CFS.