Systemic Immune-Inflammation Index as a Marker of Activity in Behcet’s Uveitis

Background: Behcet's disease (BD) is an immune-mediated disease with ocular involvement in ~70% cases. Clinical assessment of uveitis activity can be challenging in special situations. The Systemic Immune-Inflammation Index (SII), a novel biomarker, may aid assessment but remains unstudied in BD uveitis. Objective: To evaluate the levels of SII and other potential inflammatory biomarkers derived from full blood count (FBC) in patients with active uveitis in BD. Methods: This is a case-control study that included 3 groups; an active uveitis group with a confirmed diagnosis of BD, an inactive disease group with BD without any activity for at least 3 months, and a control group of age and sex-matched healthy adults. Full blood count was done for all participants from a venous sample. Neutrophil-lymphocyte ratio (NLR), Platelet-lymphocyte ratio (PLR), and SII (neutrophils × platelets/lymphocytes) were calculated and compared between the groups. Results: < .001) and the healthy controls (P .002). The cutoff value for SII was > 701.72 with 79.17% sensitivity and 100% specificity. SII levels were higher in bilateral uveitis (1232.47) compared with unilateral active uveitis (870); however, the difference was not statistically significant. Conclusion: SII was highest in BD patients with active uveitis, significantly differing from those with inactive disease and healthy controls, supporting its potential as a biomarker for uveitis activity. Further research is needed to explore its correlation with disease severity.