Lactoferrin in the gingival crevice as a marker of polymorphonuclear leucocytes in periodontal diseases

Abstract
This study examined lactoferrin (LF) levels in gingival crevicular fluid (GCF) and set out to test the hypothesis that LF could act as a marker of crevicular polymorphonuclear leucocytes (PMN). Therefore, 2 experiments were conducted: (a) to quantify total LF (ng/30 s sample) in GCF; (b) to correlate LF levels (ng/microliters) and PMN numbers (PMNs/microliters) in gingival crevicular washings (GCW). GCF was collected from 71 sites in a total of 22 patients. These sites were classified on the basis of clinical indices of gingivitis (GI) and pocket depth (PD) into three clinical groups: 'healthy', 'gingivitis' and 'periodontitis'. GCWs were obtained from an additional 63 sites in 21 patients. LF in GCF and GCWs was assayed by a sandwich ELISA. Total leucocyte and differential counts were performed on the GCWs. GCF LF (ng/30 s) correlated positively with GI (r = 0.418, p < 0.001), PD (r = 0.415, p < 0.001) and GCF volume (r = 0.624, p < 0.001). Gingivitis (n = 21) and periodontitis sites (n = 24) demonstrated significantly higher (p < 0.05) total GCF LF than healthy (n = 26) sites. In GCWs LF (ng/microliters) showed stronger correlations with clinical indices (GI: r = 0.452, PD: r = 0.513, p < 0.001) than did PMN numbers (PMNs/microliters) (GI: r = 0.279, PD: r = 0.388, p < 0.05). LF correlated strongly with PMNs in GCWs (r = 0.531, p < 0.001) and provides a simple and effective marker of crevicular PMN numbers.