IL17A polymorphism and elevated IL17A serum levels are associated with oral lichen planus.

Objective: The aim of this study was to evaluate the association of IL17A G197A polymorphism and serum levels with oral lichen planus (OLP) susceptibility and clinical presentation.
Subjects and Methods: Eighty-three individuals diagnosed with OLP and 99 healthy controls (C) were consecutively recruited. All participants had desquamating oral mucosal cells collected and DNA isolated for IL17A (G197A) genotyping. Blood samples of 42 OLP individuals and 23 healthy controls were collected for evaluation of IL17A serum levels.
Results: IL17A G197A genotypes were associated with an increased chance of having OLP (GA/AA × GG, OR = 3.44, 95% CI = 1.87-6.33, p < .001). Overall A carriers (GA or AA) were more common in OLP (38.1%) than in C (20.2%; OR = 2.43, 95% CI = 1.53-3.87, p < .001). Serum levels of IL17A were higher among patients with OLP than in healthy controls (reticular, p = .0003; erosive, p < .001), but no difference was found among the disease types.
Conclusions: IL17A G197A is associated with a higher susceptibility of developing OLP and these patients seem to present a considerable increase in IL17A serum levels. These findings suggest that Th17 cells, and IL17A in particular, may play a pivotal role in OLP pathogenesis.
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