Crevicular fluid myeloperoxidase--an indicator of acute gingival inflammation.

Paper strips inserted into 100 gingival sulci or periodontal pockets in 9 patients for 3 minutes in each case were assayed for polymorphonuclear (PMN) leukocyte-derived myeloperoxidase (MP) activity. This activity was then analysed in relation to the simultaneously recorded gingival index, probing depth and bleeding on probing. MP activity was always very low if the gingiva was clinically healthy, with no bleeding or signs of loss of attachment. However, sites at which the marginal gingiva was inflamed and bleeding and/or the pocket depth was greater than or equal to 6 mm exhibited MP activities ranging from very low to very high. The wide variation most likely reflects differing numbers of PMN cells in these crevices and is, therefore, probably indicative of acute or chronic periodontal disease at any particular site. The assays of the paper strips resulted in values linear with respect to the actual concentrations of purified, PMN cell-derived MP in the strips. Our method is a relatively simple way to quantitate the products of PMN cells at a single periodontal site and, in this way, to possibly identify the acute phases of the disease.