Relationship between antimicrobial protein levels in whole saliva and periodontitis

Antimicrobial proteins are abundant in saliva. The purpose of this study was to determine and compare the amounts of two types of antibacterial protein, cystatin and lysozyme, in saliva between healthy persons and subjects with periodontitis.

Forty subjects with periodontitis visiting Tokyo Dental College Chiba Hospital, Chiba, Japan, and 27 healthy persons were evaluated. Whole saliva was collected by requiring all subjects to expectorate into a sterile tube. Salivary levels of cystatin SA, cystatin C, and lysozyme were determined by enzyme-linked immunosorbent assay or immunoblot assay.

Cystatin SA levels in saliva from the periodontally diseased group showed a mean value of 0.063 +/- 0.026 mg/ml, statistically lower than that in the healthy group (P <0.05). The average cystatin C level in the periodontally diseased group was 2.27 +/- 1.20 ng/ml, markedly lower than that in the healthy group (3.79 +/- 1.28 ng/ml; P <0.05). Average lysozyme levels in the periodontitis and healthy groups were 16.75 +/- 15.31 microg/ml and 30.03 +/- 15.03 microg/ml, respectively. The lysozyme level in the periodontitis group was significantly lower than in the healthy group (P <0.05).

Specific monoclonal antibodies are useful for the detection of family 2 cystatins in saliva samples, and the amount of antibacterial protein in saliva offers a potential indicator of the risk for periodontitis.