Generalized aggressive periodontitis (GAgP) is an inflammatory disease of host response to bacterial challenge. To explore the role of platelets in host–microbial interactions in patients with periodontitis, 124 patients with GAgP and 57 healthy subjects were enrolled. Reliable indicators of subclinical platelet functional status, platelet count (PLT), platelet large cell ratio (PLCR), and mean platelet volume (MPV), were significantly lower in the GAgP group than in the control group and were negatively correlated with clinical periodontal parameters. The levels of important cytosolic protein in neutrophils, calprotectin (S100A8/A9) in plasma, and gingival crevicular fluid (GCF) were significantly higher in patients with GAgP compared with healthy subjects. Moreover, the GCF calprotectin level was negatively correlated with PLCR and MPV values. To explore the possible mechanisms of changes in platelet indices in periodontitis, flow cytometry analysis was performed, and patients with GAgP were found to have a higher status of platelet activation compared with healthy controls. Porphyromonas gingivalis (P. gingivalis) and recombinant human S100A8/A9 (rhS100A8/A9) induced platelet activation and facilitated platelet–leukocyte aggregate formation in whole blood of healthy subjects. In response to P. gingivalis and rhS100A8/A9, platelets from patients with GAgP increased activation and increased formation of platelet–leukocyte aggregates compared with those from healthy subjects. Platelet aggregates and platelets attached to leukocytes were found on gingival tissues from patients with GAgP, suggesting that decreased platelet size and count in the circulation might be related to consumption of large, activated platelets at inflamed gingiva. Platelets may have a previously unrecognized role in host response to periodontal infection.

Background: Epidermal growth factor (EGF) is a pro-inflammatory small peptide that stimulates cell growth, proliferation and differentiation through binding to its receptor.EGFrs2237051 and serum EGF levels have been demonstrated to be related with a variety of diseases, including several tumors and inflammatory diseases. Therefore, this study aims to investigate the association of theEGFrs2237051 variant and serum EGF levels in Chinese patients with generalized aggressive periodontitis (GAgP).Material and Methods: A case-control study was conducted among 216 patients with GAgP and 138 healthy controls. The clinical parameters of plaque index, probing depth, attachment loss and bleeding index were recorded. TheEGF rs2237051polymorphism was genotyped using time-of-flight mass spectrometry, and serum EGF levels were determined. Logistic and linear regression models were used to investigate the association between the genotypes ofEGFrs2237051, serum EGF levels and GAgP risk.Results: The AA genotype ofEGFrs2237051 showed higher risk for GAgP than the combined genotypes GG and AG (adjusted OR = 1.65, 95% CI [1.06–2.57]). Increased serum EGF levels were associated with GAgP (adjusted OR = 1.18, 95% CI [1.14–1.22]). Moreover, the serum EGF level for the AA genotype was significantly higher than that for the AG/GG genotypes in patients with GAgP (adjusted β = 4.70, 95% CI [2.09–7.31]).Conclusion: We demonstrated thatEGFrs2237051 variant and the increased level of serum EGF were associated with the risk of GAgP, the serum EGF was up-regulated in patients with GAgP. It was indicated that serum EGF might be a biomarker of GAgP andEGFrs2237051 may be related to the genetic background of GAgP.