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

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.

To evaluate the levels of SII and other potential inflammatory biomarkers derived from full blood count (FBC) in patients with active uveitis in BD.

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.

58 subjects were enrolled; 24 patients with BD and current active uveitis, 15 patients with inactive BD, and 19 healthy matched volunteers. The NLR and PLR were significantly higher in the active uveitis group than in the inactive group. SII was higher in the active uveitis group compared with the inactive group (P < .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.

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.