Phagocytosis of periodontopathogenic bacteria by crevicular granulocytes is depressed in progressive periodontitis

Background: The aim of this study was to examine crevicular polymorphonucle ar neutrophils (PMN) of patients with rapidly progressive periodontitis (RP P) for their in vitro phagocytic activity and intracellular killing of Porp hyromonas gingivalis ATCC 33277 and two strains of Actinobacillus actinomyc etemcomitans (NCTC 9710 - type strain and Tanner FDC 44 - leukotoxin produc ing strain). Patients and Methods: 18 patients with RPP and nine healthy controls were i ncluded in the study. Phagocytosis and intracellular killing were assessed by fluorescence microscopy after staining with acridine orange. The percent age of phagocytosing PMN was determined. The phagocytic cells were then sep arated into two groups; those containing < 10 phagocytosed bacteria and tho se containing > 10 bacteria. The percentage of PMN containing viable bacter ia was also determined. Results: The leukotoxic A. actinomycetemcomitans strain was phagocytosed to a lesser degree than the corresponding type strain. The number of phagocyt osing cells obtained from the RPP patients did not differ from the controls . However, in healthy subjects there were more phagocytes with more than te n ingested P. gingivalis than in RPP patients. The intracellular killing wa s diminished in the periodontitis group for P. gingivalis and for both A. a ctinomycetemcomitans strains. Conclusion: The PMN of patients with RPP show deficiencies in phagotcytic a ctivity and in the intracellular killing or peridontopathogenic bacteria.