In Vitro Lymphocyte Stimulation by Simonsiella in Patients with Oral Lichen Planus

The relationship between cell-mediated immunity to sonicated whole cell extract of Simonsiella and lichen planus was investigated in 15 patients with lichen planus, 14 control diseases subjects and 14 controls with healthy oral mucosa by in vitro lymphocyte stimulation. The mean stimulation index was highest in lichen planus group (SI=13.8 ± 2.98), followed by the control diseases group (SI=10.9 ± 2.03) and finally by healthy control group (SI=7.2 ± 1.67). However, there was no statistically significant difference ( p > 0.5) in the level of lymphocyte proliferation induced by Simonsiella between lichen planus and both control groups. In vitro lymphocyte proliferation induced by Simonsiella was also compared in patients with erosive and non-erosive lichen planus. Lymphocytes from patients with non-erosive lichen planus responded by enhanced stimulation (mean SI=18.5 ± 4.72) when compared with lymphocytes from patients with erosive lichen planus (mean SI=8.3 ± 2.31). However, this difference was not statistically significant. These results show that there is no association between in vitro cell-mediated immunity to Simonsiella and lichen planus. However, they suggest the existence of natural cellular immunity to Simonsiella in man. Keywords: In vitro cell mediated immunity; Simonsiella ; Lichen planus; Oral flora; Erosive oral lesions.