Meta-analysis reports elevated IL-6 and IL-17 in thyroid eye disease patients

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Frontiers in Medicine Published May 8, 2026 Medically reviewed May 8, 2026 DOI ↗ By Dr. Amelia Tan, PhD · Internal Medicine & Chronic Disease

Key Takeaway

Consider that IL-6 and IL-17 levels are elevated in thyroid eye disease, but findings are observational and not causal.

This is a meta-analysis of observational studies examining cytokine levels in patients with thyroid eye disease (TED) and controls. The scope was to synthesize evidence on serum or tear levels of IL-6 and IL-17 as potential biomarkers. The authors found that IL-6 levels in TED patients were significantly elevated compared to controls, with a pooled standardized mean difference (SMD) of 1.68 (95% CI: 0.83–2.53). IL-17 levels were markedly higher in TED patients, with a pooled SMD of 1.78 (95% CI: 1.18–2.37). The analysis also indicated that both IL-6 and IL-17 levels were significantly higher in active TED versus inactive TED, though effect sizes were not reported for this comparison. The authors acknowledge substantial heterogeneity in the IL-6 results, which limits the certainty of the pooled estimate. They note that the findings describe the circulating cytokine profile in the studied population and may inform future hypothesis-driven research. The review does not report on study populations, interventions, or adverse events, as these details were not provided in the source. Practice relevance is restrained to generating hypotheses rather than guiding clinical decisions.

Study Details

Study typeMeta analysis

EvidenceLevel 1

PublishedMay 2026

View Original Abstract ↓

BackgroundThyroid Eye Disease (TED) is the most common extrathyroidal manifestation of Graves’ disease. Interleukin-6 (IL-6) and interleukin-17 (IL-17) have been implicated in its pathogenesis, but individual study results remain inconsistent. However, existing findings on IL-6 and IL-17 levels in the serum or tears of TED patients remain inconsistent.AimThis meta-analysis aimed to statistically evaluate the level of IL-6 and IL-17 in patients with TED.MethodsA systematic literature search was conducted across five electronic databases (PubMed, Web of Science, Elsevier Science Direct, Wiley Online Library, and CNKI). The search strategy targeted the terms “Thyroid Eye Disease” in conjunction with “Interleukin-6” or “Interleukin-17” in title and abstract fields. Results are presented as standardized mean differences (SMD) with 95% confidence intervals (CI).ResultsThis meta-analysis demonstrated significantly elevated levels of both IL-6 and IL-17 in patients with TED compared to controls. Pooled estimates showed a substantial increase in IL-6 (SMD: 1.68; 95% CI: 0.83–2.53), with substantial heterogeneity. Similarly, IL-17 levels were markedly higher in TED patients overall (SMD: 1.78; 95% CI: 1.18–2.37). Furthermore, patients with active TED exhibited significantly higher IL-6 and IL-17 levels than those with inactive disease.ConclusionsTo our knowledge, this meta-analysis is a large-scale systematic evaluation of IL-6 and IL-17 levels in patients with TED. These findings describe the circulating cytokine profile in the studied population and may inform future hypothesis-driven research.Systematic Review Registrationhttps://www.crd.york.ac.uk/PROSPERO/view/CRD420261277844, identifier CRD420261277844.