Increased adhesion of peripheral blood neutrophils from patients with localized juvenile periodontitis

Adhesion of peripheral blood neutrophils from 5 patients with localized juvenile periodontitis (LJP) and age- and gender-matched healthy controls was measured using a semi-automated 96-well microtiter plate assay method. Both unstimulated and formyl-methionyl-leucyl-phenylalanine (FMLP, 10-1000 nM)-stimulated neutrophils from LJP patients showed in general higher adhesion than did their controls. After 15-60 min incubation with 100 and 1000 nM FMLP the numbers of adherent cells were significantly (p < 0.05), 2.1-2.6-fold higher in LJP patients than in controls. Neutrophils from these LJP patients showed also enhanced respiratory burst activity in response to unopsonized zymosan stimulation. To test whether a decrease in intracellular diacylglycerol (DAG) kinase activity could account for the increased neutrophil adhesion of LJP patients normal neutrophils were treated with R59949 (10 microM), a DAG-kinase inhibitor. Both unstimulated and FMLP-stimulated normal neutrophils showed significantly (p < 0.05) enhanced adhesion after R59949-treatment. Taken together, our data indicate that neutrophils from the 5 LJP patients investigated here exhibit 2 parallel hyperactivities, namely increased adhesion and enhanced production of reactive oxygen species. Furthermore, our present and previous (Hurttia et al., J Periodont Res 1997; 32: 401-407) results suggest that the observed neutrophil functional abnormalities in some LJP patients may be associated with decreased cellular DAG-kinase activity. It is proposed that the hyperadherent and -active neutrophils may promote the development of LJP by causing tissue damage in the periodontium.