BPI modulates IL-1β-driven inflammation in periodontitis: A case-control study in gingival crevicular fluid

Bactericidal/permeability-increasing protein (BPI) is a neutrophil-derived antimicrobial protein with high affinity for lipopolysaccharide (LPS) of gram-negative bacteria. This study aimed to compare BPI and interleukin-1 beta (IL-1β) levels in gingival crevicular fluid (GCF) between healthy and diseased individuals and to investigate their correlation with clinical parameters. We collected GCF from 50 consecutive ≥18 to <65 years old individuals with generalized periodontitis (P group) and 50 consecutive healthy individuals (H group). Clinical periodontal parameters were documented. IL-1β and BPI levels from GCF were analyzed via ELISA. Receiver operating characteristic (ROC) analysis was performed to evaluate diagnostic performance. GCF levels of BPI and IL-1β were significantly higher in the periodontitis group compared to healthy controls (p < 0.001). Both biomarkers demonstrated strong positive correlations with clinical parameters (p < 0.01). Strong positive correlations were found between GCF BPI levels and GCF IL-1β levels in the P group (P ˂ 0.01). ROC analysis revealed that BPI had a sensitivity of 100 % and an area under the curve (AUC) of 0.76 for detecting periodontitis but low specificity (50 %, AUC = 0.76), while IL-1β had a specificity of 86 % and sensitivity of 72 %. Elevated GCF levels of BPI and its correlation with IL-1β and clinical periodontal measures suggest that BPI might play a dual role in host response by contributing to microbial elimination and regulating inflammation.