E2 ModerateModerate confidencePEM not requiredCross-SectionalPeer-reviewedReviewed
Standard · 3 min
Detection of antinuclear antibodies by indirect immunofluorescence and by solid phase assay.
Op De Beeck, Katrijn, Vermeersch, Pieter, Verschueren, Patrick et al. · Autoimmunity reviews · 2011 · DOI
Quick Summary
This study compared two different blood tests for detecting antinuclear antibodies (proteins the immune system sometimes makes against the body's own cells). Researchers tested these methods in people with autoimmune diseases, healthy people, ME/CFS patients, and other disease controls. The newer solid phase test was better at correctly identifying people with certain autoimmune diseases, though both tests rarely showed false positives in ME/CFS patients.
Why It Matters
This study is relevant to ME/CFS research because it provides baseline data on antinuclear antibody prevalence in ME/CFS patients (showing <4% reactivity), helping distinguish ME/CFS from autoimmune connective tissue diseases. Understanding which diagnostic tests accurately differentiate ME/CFS from autoimmune conditions is important for proper patient classification in research and clinical care.
Observed Findings
Antinuclear antibody reactivity was <4% in ME/CFS patients using the EliA CTD Screen assay
The EliA CTD Screen showed 74% sensitivity for systemic lupus erythematosus and 100% sensitivity for mixed connective tissue disease
Positive EliA CTD Screen results had higher likelihood ratios for rheumatic disease than positive indirect immunofluorescence results
Negative indirect immunofluorescence results had lower likelihood ratios (higher negative predictive value) than negative EliA CTD Screen results
Antibody concentration correlated with increasing likelihood ratios in EliA assay results
Inferred Conclusions
Solid phase assays (EliA CTD Screen) may be more useful than indirect immunofluorescence for detecting antinuclear antibodies in patients suspected of having systemic rheumatic diseases
Indirect immunofluorescence remains valuable for ruling out rheumatic disease when results are negative
Antinuclear antibodies are rarely present in ME/CFS patients, supporting their utility in differential diagnosis
Remaining Questions
Why does indirect immunofluorescence have superior negative predictive value despite EliA detecting more antigens, and what antigens account for this difference?
What This Study Does Not Prove
This study does not prove that antinuclear antibodies cause or contribute to ME/CFS pathogenesis—it only describes their presence or absence. It also does not establish whether antinuclear antibodies play any functional role in either ME/CFS or rheumatic disease; it is purely a diagnostic performance comparison. The cross-sectional design cannot determine whether antibody status changes over time or precedes symptom development.
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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