The Role of Neutrophil to Lymphocytes Ratio (NLR) as a Predictor of Disease Activity in Behcet’s Syndrome—A Comprehensive Review

Behçet's syndrome (BS) is a chronic, relapsing inflammatory disease with multisystem involvement and prominent neutrophil activation. The neutrophil-to-lymphocyte ratio (NLR) has gained increasing attention as a potential surrogate marker for systemic inflammation. In this review we aimed to summarize and critically review the current evidence regarding the utility of NLR in BS, including its association with overall disease activity and specific organ involvement, as well as to explore its strengths and limitations as a clinical biomarker. NLR seems to be a simple, accessible, and cost-effective biomarker that can be elevated in Behçet's syndrome and tends to be higher during active disease. Studies have demonstrated its consistent correlation with overall disease activity, as well as with specific manifestations such as mucocutaneous, ocular, vascular, and articular involvement. Moreover, NLR levels have been shown to decrease in response to anti-inflammatory treatments, supporting its potential utility in monitoring treatment effectiveness. Despite its seemingly cost-effective features, its routine integration into daily practice remains largely limited, mainly due to low specificity and the lack of standardized cut-off level. Further prospective studies are needed to assess its use in daily practice before it can be integrated into any disease activity score.