Effects of nonopsonized Escherichia coli on myeloperoxidase activity in medium used for incubation of leukocytes from patients with gingivitis and periodontitis.

An attempt was made to explore the myeloperoxidase (MPO) activity in medium used for incubation of peripheral venous blood (PVB) leukocytes from patients with gingivitis and periodontitis and to compare it with that of periodontally healthy subjects. The study population included 54 gingivitis patients (G), 52 periodontitis patients (P) and 52 control subjects (C). All these groups were assessed by clinical, laboratory and statistical methods. The leukocytes were incubated with opsonized zymosan, Escherichia coli ATCC25922, nonopsonized E.coli or Staphylococcus aureus 256. The respective levels of MPO activity in incubation media of PVB leukocytes taken from group G patients were 598.0 +/- 29.2 conventional units (c.u.), 640.0 +/- 26.3 c.u., 662.0 +/- 37.6 c.u. and 750.0 +/- 40.8 c.u. (control incubation medium: 564.0 +/- 25.1 c.u.); those for group P patients were 672.0 +/- 34.3 c.u., 678.0 +/- 43.1 c.u., 692.0 +/- 47.9 c.u. and 762.0 +/- 34.7 c.u. (control: 612.0 +/- 35.2 c.u.); those for group C subjects were 556.0 +/- 30.2 c. u., 714.0 +/- 28.2 c.u., 1276.0 +/- 69.0 c.u. and 794.0 +/- 47.1 c.u. (control: 534.0 +/- 29.0 c.u.). MPO activity was increased most significantly when nonopsonized E.coli was added to the incubation medium of PVB leukocytes taken from subjects with intact periodontium. MPO activity was unchanged when the leukocytes were taken from periodontitis patients.