E3 PreliminaryPreliminaryPEM unclearMethods-PaperPeer-reviewedMachine draft
Autoantibodies to lens epithelium-derived growth factor/transcription co-activator P75 (LEDGF/P75) in children with chronic nonspecific complaints and with positive antinuclear antibodies.
Kuwabara, Natsuko, Itoh, Yasuhiko, Igarshi, Tohru et al. · Autoimmunity · 2009 · DOI
Quick Summary
This study found that a specific antibody called anti-Sa, detected in people with chronic fatigue and positive autoimmune markers, is actually targeting a protein called LEDGF/p75. Researchers developed a simple blood test (ELISA) to detect this antibody more accurately than previous methods. This new test could help doctors identify which patients with chronic fatigue may have an autoimmune component to their illness.
Why It Matters
Identifying specific autoantibodies in ME/CFS patients could provide an objective diagnostic biomarker and suggest autoimmune mechanisms underlying the disease. A standardized ELISA assay for anti-LEDGF/p75 may enable consistent diagnosis and help stratify CFS patients for research and clinical trials. This work bridges findings from different research groups and provides a practical diagnostic tool.
Observed Findings
- Anti-Sa antibodies detected by Western blot and anti-LEDGF/p75 antibodies detected by ELISA were identical in 226 AIFS sera (36 of which were from CFS patients).
- Recombinant LEDGF/p75 protein successfully inhibited anti-Sa reactivity on Western blot when used as a pre-incubation reagent.
- Antibodies eluted from Western blot nitrocellulose membranes reacted with LEDGF/p75 on the newly developed ELISA assay.
- Approximately 40% of AIFS patients were anti-Sa positive by Western blot.
Inferred Conclusions
- The Sa antigen is definitively LEDGF/p75, confirming earlier findings that anti-Sa and anti-DFS70 represent the same antibody specificity.
- A recombinant protein-based ELISA assay is a valid and potentially superior method for detecting anti-LEDGF/p75 compared to Western blot.
- The anti-LEDGF/p75 ELISA could serve as a diagnostic tool for identifying CFS patients with an autoimmune component.
Remaining Questions
- What is the functional or pathological role of anti-LEDGF/p75 antibodies in CFS pathogenesis?
- Do anti-LEDGF/p75 antibodies correlate with disease severity, symptom profiles, or prognosis in CFS patients?
- What is the prevalence of anti-LEDGF/p75 in unselected CFS populations and in healthy controls?
What This Study Does Not Prove
This study does not prove that anti-LEDGF/p75 causes CFS or that it is present in all CFS patients—only that it appears in some AIFS and CFS patients with positive ANA. The study does not establish the clinical significance, pathological role, or prognostic value of this antibody. The cross-sectional design cannot determine whether the antibody precedes symptom onset or is merely an epiphenomenon.
Tags
Symptom:Fatigue
Biomarker:AutoantibodiesBlood Biomarker
Phenotype:Pediatric
Method Flag:Weak Case DefinitionSmall SampleExploratory OnlyMixed Cohort
Metadata
- DOI
- 10.1080/08916930902736663
- PMID
- 19657776
- Review status
- Machine draft
- Evidence level
- Early hypothesis, preprint, editorial, or weak support
- 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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