Oral and serum IL-6 levels in oral lichen planus patients

The purpose of this study was to compare IL-6 levels in oral exfoliated mucosal cell samples and in serum in subjects with oral lichen planus versus controls. Study design Ten patients with ulcerative OLP, 10 with reticular OLP, and 10 control subjects were recruited at a University Oral Medicine Clinic. Using smear tissue culture brushes, oral samples were collected from lesional sites for OLP patients and from buccal mucosa for controls into vials with 300 muL PBS. After centrifugation, the supernatants were aspirated for cytokine ELISA assay and protein assay. Venous blood was processed to serum for ELISA assay. Oral IL-6 was expressed as both pg/mL and pg/mug protein, and serum IL-6 was expressed as pg/mL.

The mean oral IL-6 levels were higher in the ulcerative OLP group (11.19 +/- 5.34 pg/mL) than in the reticular OLP (1.05 +/- 0.34 pg/mL) and control (0.52 +/- 0.29 pg/mL) groups. There were significant differences between ulcerative OLP and reticular OLP groups (P < .039), and between ulcerative OLP and control groups (P < .009). After the standardization of IL-6 concentration by protein, a significant difference in IL-6 concentration was shown only between the ulcerative OLP (0.0245 +/- 0.0121 pg/mug protein) and control (0.0023 +/- 0.0012 pg/mug protein) groups (P < .029). Similarly, the ulcerative OLP group showed a significantly higher serum IL-6 level than the control group (P < .021).

Both oral and serum IL-6 levels were higher in patients with ulcerative OLP. An oral exfoliated cell technique may be a useful and sensitive method to measure IL-6 in patients with OLP as it provided results consistent with those found in peripheral blood.