Calprotectin in GCF as a predictive biomarker in periodontal therapy

Objectives: Clinical parameters such as probing depth (PD) and bleeding on probing (BOP) are common determinants for monitoring of periodontal disease activity and are applied for determination of sites at risk for disease progression and for specification of treatment need. However, these parameters merely reflect pathologic effects of previous inflammation and their ability to predict future disease activity is very low. Calprotectin, a marker substance for neutrophil granulocytes, is used for monitoring of other inflammatory conditions (e.g. inflammatory bowel disease) according to its excellent ability to predict a clinical relapse. Calprotectin is detectable in gingival crevicular fluid (GCF) and correlates to clinical disease severity and treatment outcome in patients with periodontal disease. However, the validity of calprotectin as a predictor for future periodontal disease activity has not been analysed.

Methods: Thirty-six periodontitis patients were monitored during supportive therapy in three month intervals after conclusion of non-surgical therapy. GCF samples were collected at one site/patient. PD, clinical attachment level (CAL) and BOP were assessed with an electronic constant-force periodontal probe. Calprotectin levels in GCF were determined with an ELISA kit. Sites presenting a PD increase > 0.5 mm within three months were considered as ‘relapse'. The ability of individual parameters to predict a ‘relapse' was analysed by construction of ROC curves and contingency tables.

Results: Nine sites with PD increase > 0.5 mm were identified. Clinical parameters (CAL, PD, BOP, GCF volume) were unable to predict a suchlike ‘relapse' (area under the curve AUC<0.6, p>0.05). However, both calprotectin concentration (AUC=0.793, p=0.01) and total amount/sample (AUC=0.776, p=0.02) significantly predicted a subsequent increase of PD with a corresponding positive predictive value of 44% and a negative predictive value of 94%.

Conclusions: In contrast to clinical parameters, calprotectin in GCF did significantly predict a subsequent increase of PD at the monitored site.