A population-based study of salivary lysozyme concentrations and candidal counts

The relationship between salivary lysozyme concentration and oral candida load was examined in 595 adults. Unstimulated whole saliva, and citrate-stimulated parotid and submandibular/sublingual saliva were collected from each participant. Candida colony-forming units (c.f.u.) in unstimulated whole saliva were determined. An enzyme-linked immunosorbent assay for lysozyme using commercially available antibodies was developed. This assay showed a linear relation of salivary lysozyme concentrations from 0.5 to 4.0 ng/ml. Significant negative relations were observed between lysozyme concentration and flow rate; r = −0.16 (p < 0.001) for stimulated parotid and r = −0.22 (p < 0.0001) for stimulated submandibular/sublingual saliva. The lysozyme concentration in stimulated submandibular/sublingual saliva was higher in males than in females, but no sex difference was observed for stimulated parotid saliva. The lysozyme concentration of stimulated parotid saliva was positively correlated with candida counts (r = 0.18; p < 0.005). Further study of groups according to their levels of candida in whole saliva revealed that lysozyme concentrations were higher in the high candida (⩾1000 c.f.u./ml) group than in the zero and moderate candida categories in stimulated parotid saliva (p < 0.001); there were no concentration differences in stimulated submandibular/sublingual saliva. These results suggest that parotid lysozyme concentration increases as candida load increases.