Phagocytic functions of salivary neutrophils in oral mucous membrane diseases

Phagocytic functions of salivary polymorphonuclear neutrophils (sPMNs) have not been comprehensively studied in patients with oral mucous membrane diseases, although available data suggest the role of immunity in their pathogenesis.

Phagocytic functions of sPMN were determined in 15 patients with acute recurrent aphthous ulceration (RAU), 11 patients with oral lichen planus (OLP) and 20 healthy volunteers. In healthy subjects, the same parameters were also determined in peripheral blood polymorphonuclear neutrophils (bPMNs). Phagocytic activity (proportion of ingesting cells, PA), ingestion ability (number of ingested targets per 100 phagocytes, IA) and intracellular microbicidity (proportion of killed targets, IM) of PMNs separated from peripheral blood and the whole unstimulated saliva were determined by acridine orange method with living yeast cells as targets.

Salivary PMNs in healthy individuals showed significant reduction in PA (33% vs. 76%; P < 0.009) and IA (0.47% vs. 2.93%; P < 0.009) and significant increase in IM (12.0% vs. 5.5%; P = 0.011) in comparison with bPMNs. In RAU patients, reduced PA (27% vs. 37%; P = 0.035) and IA (0.25% vs. 0.47%; P = 0.05) were detected, while in OLP patients enhanced IM was detected (12% vs. 19%; P = 0.033) in comparison with healthy controls.

Salivary PMNs present functional features distinct from those in peripheral blood. Some phagocytic functions of sPMNs are reduced in RAU and enhanced in OLP, indicating their role in pathogenesis or reflecting clinical changes in these conditions.