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

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.