Secretion of antimicrobial proteins from the parotid glands of different aged healthy persons.

The secretion of three antimicrobial proteins from the parotid glands of 82 generally healthy men and women, 22 to 81 years in age, was examined. No change was observed in the levels of secretory IgA, but statistically significant, modest elevations (approximately 50 to 100%) of lactoferrin, in both unstimulated and stimulated secretions, and lysozyme, in unstimulated secretions, were detected when results were expressed as mg antimicrobial protein/100 ml saliva. However, these alterations were not observed if data were expressed as mg antimicrobial protein/g total protein. Also, no change was detected in an acinar cell exocrine product, the anionic proline-rich proteins, as reported previously by our laboratory. The data are consistent with a maintenance of protective functions in parotid saliva during aging.