Circulating S100A8/A9 Levels Reflect Intraocular Inflammation in Uveitis Patients

Purpose: To investigate whether there is an association between circulating S100A8/A9 levels and uveitis activity. Methods: A total of 549 plasma samples were collected from uveitis patients and non-uveitic controls. Results: S100A8/A9 plasma levels were elevated in uveitis patients compared to non-uveitic controls (P < 0.001). S100A8/A9 plasma levels in patients with active acute anterior uveitis (AAU) were significantly elevated and remarkably decreased in parallel with the severity of intraocular inflammation after corticosteroid treatment (P < 0.001). S100A8/A9 plasma levels were also higher in AAU patients with ankylosing spondylitis (AS) than in patients without AS (P = 0.02). S100A8/A9 plasma levels were significantly increased in uveitis patients with elevated C-reactive protein (CRP, P = 0.004) or erythrocyte sedimentation rates (ESR, P = 0.049) levels compared to uveitis patients with normal CRP or ESR values. Conclusion: Circulating S100A8/A9 might be a useful biomarker for the measurement of intraocular inflammation.