Immunoexpression of Th17-related Cytokines in Oral Lichen Planus

A recently described lineage of lymphocytes, Th17 cells, has been associated with inflammatory and autoimmune diseases. The aim of this article was to assess the immunoexpression of cytokines related to this lineage, interleukin-17 (IL-17) and IL-23 and in reticular and erosive oral lichen planus (OLP). The sample included 41 cases of OLP (23 reticular and 18 erosive) and 10 cases of inflammatory fibrous hyperplasia (IFH). Lymphocytes exhibiting cytoplasmic immunostaining were counted. Epithelial immunostaining was also evaluated. There was no statistical differences in the number of IL-17(+) and IL-23(+) lymphocytes between the OLP (55.40 and 48.40, respectively) and IFH (39.30 and 44.40, respectively). A significantly higher number of IL-23(+) lymphocytes was found in erosive OLP group (63.80) when compared with reticular (41.40) and IFH lesions (44.40) (P=0.019). Furthermore, epithelial immunopositivity for IL-17 and IL-23 was higher in OLP lesions than in IFH (P=0.012 and P=0.011, respectively). A significantly higher number of IL-23(+) lymphocytes in erosive OLP and the strong epithelial immunopositivity for IL-23 and IL-17 in OLP group could suggest an important participation of TCD4(+) Th17 response in this disorder.