A systematic review of cytokines in chronic fatigue syndrome/myalgic encephalomyelitis/systemic exertion intolerance disease (CFS/ME/SEID).

Corbitt, Matthew, Eaton-Fitch, Natalie, Staines, Donald et al. · BMC neurology · 2019 · DOI

Quick Summary

Researchers reviewed 15 studies that measured immune signaling molecules called cytokines in people with ME/CFS compared to healthy people. Although many studies have looked at cytokines in ME/CFS, the results were too mixed and inconsistent to show that cytokines could be used as a reliable test for the condition or to confirm a clear role in causing the disease.

Why It Matters

Identifying reliable biomarkers is critical for ME/CFS diagnosis and treatment development, as the condition currently lacks objective diagnostic tests. This review reveals that while cytokine research is active, the field has not yet produced consistent enough evidence to move cytokines into clinical use, highlighting the need for more rigorous, standardized research approaches.

Observed Findings

15 studies met inclusion criteria after screening 16,702 publications
All included studies were observational case-control designs
Ten studies measured serum cytokines; four measured cytokines in other physiological fluids
Most included studies demonstrated consistent methodology and moderate quality
Findings across studies were too heterogeneous to reach definitive conclusions about cytokine differences

Inferred Conclusions

Cytokines cannot currently serve as reliable biomarkers for ME/CFS diagnosis
Despite moderate quality evidence, available research is inconclusive regarding whether cytokines play a definitive pathological role in ME/CFS
Further research using standardized methodologies is needed to clarify cytokine involvement in the disease

Remaining Questions

What methodological standardization is needed across cytokine studies to produce consistent, comparable results?
Are specific cytokine profiles or combinations more relevant to ME/CFS pathology than individual cytokine measurements?
Could longitudinal studies tracking cytokine changes over time reveal patterns that cross-sectional studies miss?
What role do measurement timing, sample collection methods, and patient stratification play in the inconsistency of findings?

What This Study Does Not Prove

This review does not prove that cytokines play no role in ME/CFS—only that current evidence is too inconsistent to establish them as reliable diagnostic markers. It also does not identify which specific cytokines, if any, are meaningfully altered in ME/CFS, nor does it establish causative relationships between cytokine abnormalities and disease symptoms.

Topics

Biomarkers Immune Dysregulation

Metadata

DOI: 10.1186/s12883-019-1433-0
PMID: 31445522
Review status: Editor reviewed
Evidence level: Established evidence from major reviews, guidelines, or evidence maps
Last updated: 7 April 2026