E2 ModerateModerate confidencePEM not requiredObservationalPeer-reviewedMachine draft
A study of the immunology of the chronic fatigue syndrome: correlation of immunologic parameters to health dysfunction.
Hassan, I S, Bannister, B A, Akbar, A et al. · Clinical immunology and immunopathology · 1998 · DOI
Quick Summary
This study examined immune system markers in 44 people with ME/CFS to see how these markers related to symptom severity and mental health. Researchers found that ME/CFS patients had unusual patterns in their immune cells—specifically, signs of increased immune activation and changes in how lymphocytes (white blood cells) behave. These immune changes correlated with worse physical function, pain, and mental health symptoms.
Why It Matters
This study provided early evidence that ME/CFS involves measurable immune system dysfunction, not psychological illness alone. Understanding how specific immune abnormalities correlate with symptom severity may help develop targeted treatments and validate ME/CFS as a biological condition.
Observed Findings
- Increased HLA-DR expression on CD4 and CD8 cells in CFS patients compared to controls (P < 0.05)
- Reduced CD28 costimulatory receptor expression on CD8 cells in CFS patients
- Increased bcl-2/bax apoptosis-repressor ratio in both CD4 and CD8 cells
- Elevated HLA-DR expression correlated with lower SF-36 total scores, worse body pain, and poorer physical functioning
- Reduced PHA proliferative responses associated with poor emotional and mental health scores
Inferred Conclusions
- T-lymphocytes show signs of immunoactivation and terminal differentiation in ME/CFS, consistent with possible viral etiopathogenesis
- Increased bcl-2 expression may enhance survival of activated lymphocytes in ME/CFS
- Specific immune parameters correlate with distinct aspects of disease symptomatology including physical function and mental health
Remaining Questions
- Are these immune abnormalities specific to ME/CFS or do they occur in other conditions?
- Do immune changes precede symptom onset or result from prolonged illness?
- Which immune abnormalities drive symptoms versus which are secondary compensatory responses?
What This Study Does Not Prove
This study does not prove that immune changes cause ME/CFS symptoms—only that they correlate. The cross-sectional design cannot establish causality or temporal relationships. It also does not demonstrate whether these immune changes are specific to ME/CFS or occur in other conditions, and it does not establish which immune changes are primary versus secondary responses.
Tags
Symptom:PainFatigue
Biomarker:CytokinesBlood Biomarker
Method Flag:PEM Not DefinedWeak Case DefinitionNo ControlsSmall SampleExploratory Only
Metadata
- DOI
- 10.1006/clin.1997.4512
- PMID
- 9576011
- Review status
- Machine draft
- Evidence level
- Single-study or moderate support from human research
- Last updated
- 8 April 2026
About the PEM badge: “PEM required” means post-exertional malaise was an explicit required diagnostic criterion for participant inclusion in this study — not that PEM was studied, observed, or discussed. Studies using criteria that do not require PEM (e.g. Fukuda, Oxford) are tagged “PEM not required”. How the atlas works →
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