Gingival sulcular leukocytes in periodontitis and in experimental gingivitis in humans

Leukocytes may play an important defensive role against plaque microorganisms in the periodontium. The aim of the present study was to characterize some functional and morphological aspects of sulcular leukocytes in periodontitis and in experimental gingivitis in humans. In a cross-sectional study, cells were collected from periodontal pockets or from gingivitis (control) sites of patients with periodontitis. In a longitudinal study, cells were obtained from experimental or from control sites during a split-mouth experimental gingivitis. Leukocytes were examined for cell numbers, viability, phagocytic function, and morphology.
The cell numbers in periodontal pockets were higher than in control sites but the cell viability had a tendency to decrease. A significant decrease was also observed in the percent of leukocytes capable of phagocytizing Candida albicans in vitro in periodontitis sites compared to gingivitis sites. In the experimental gingivitis, the cell numbers showed a significant increase from day 0 to day 21 of the non-brushing period in the experimental sites when compared to the control sites. However, the cell viability did not vary significantly between the experimental and the control sites during the experimental period. No significant variations were observed in the leukocyte in vitro phagocytic function during the same period. Polymorphonuclear leukocytes collected from the sulcus presenting different clinical situations showed various degrees of phagocytosis, loss of lysosomes, and cell lysis, but no correlation could be established between these observations and the clinical status.