The role of low-grade inflammation in ME/CFS (Myalgic Encephalomyelitis/Chronic Fatigue Syndrome) - associations with symptoms.
Jonsjö, Martin A, Olsson, Gunnar L, Wicksell, Rikard K et al. · Psychoneuroendocrinology · 2020 · DOI
Quick Summary
This study looked at whether low-level inflammation in the blood is connected to ME/CFS symptoms like exhaustion after activity, brain fog, muscle pain, and flu-like illness. Researchers tested 53 ME/CFS patients for various inflammatory markers and found that several of these markers were associated with cognitive problems and pain, though they were surprisingly less connected to post-exertional fatigue. Interestingly, the connection between inflammation and symptoms was different for men and women in some cases.
Why It Matters
This study helps identify which inflammatory pathways may underlie specific ME/CFS symptoms, particularly cognitive impairment and pain—offering potential biomarkers for future research and clinical assessment. The finding that sex influences these inflammatory associations suggests that ME/CFS may manifest differently in men and women, which could have implications for personalized treatment approaches.
Observed Findings
β-NGF was the only inflammatory marker significantly associated with post-exertional fatigue severity.
CCL11, CXCL10, IL-7, TNF-α, and TGF-β-1 were significantly associated with impaired cognitive processing.
CCL11, CXCL10, IL-7, TNF-α, and TGF-β-1 were significantly associated with musculoskeletal pain.
Sex significantly moderated the relationship between CXCL10, IL-7, TGF-β-1 and symptoms, suggesting different inflammatory patterns in men versus women.
No inflammatory markers showed consistent associations with recurrent flu-like symptoms.
Inferred Conclusions
Low-grade inflammation may contribute differently to various ME/CFS symptoms, with stronger associations for cognitive and pain symptoms than for post-exertional fatigue.
Sex differences in inflammatory responses warrant investigation as a potential biological basis for symptom variation between men and women with ME/CFS.
Longitudinal studies are needed to determine whether inflammatory markers predict symptom development or persistence.
Remaining Questions
Do these inflammatory markers change over time and predict symptom progression or improvement in individual patients?
Why does post-exertional fatigue show weak association with these inflammatory markers compared to cognitive symptoms and pain?
What This Study Does Not Prove
This study cannot establish that inflammation causes ME/CFS symptoms; it only shows statistical associations. The cross-sectional design means we cannot determine whether inflammation precedes symptoms, follows them, or both. The small sample size limits the strength of conclusions and may not represent all ME/CFS patients.