Evaluation of correlation between transcription factors and IL-17 in oral and cutaneous lichen planus lesions and Leukocytes

Background: Lichen planus (LP) is a chronic autoimmune disease with different clinical subtypes including cutaneous LP (CLP) and oral LP (OLP). We aimed to compare mRNA expression of ROR gamma t and IL-17 in paraffin-embedded blocks of OLP and CLP lesions with normal oral mucosa (NOM), and also its correlation with hematologic parameters. Materials & methods: This study included 89 paraffin-embedded blocks contain OLP (44 cases), CLP (45 cases) and NOM from the archive of Mashhad University of Medical Sciences, Mashhad, Iran. The expression of ROR gamma t and IL-17 was evaluated by Real-time RT-PCR method. The result was compared to Leukocyte counts and the other hematological parameters of studied patients. Results: The results of our study showed IL-17 and ROR gamma t expression in OLP lesions were significantly higher than CLP and NOM groups (P = 0.001). Although we found high expression of ROR gamma t and IL-17 in erosive OLP in compared to classic OLP lesion, but this increment was not significant for IL-17 (P = 0.26) and RORt (P = 0.14). Further, Leukocyte and monocyte counts were substantially high in OLP group in compared to the CLP and NOM groups (P < 0.05). Conclusions: We concluded that increased expression of ROR gamma t and IL-17 in LP lesions could play role in the pathogenesis of LP. As well, higher expression of ROR gamma t and IL-17 in oral LP more than cutaneous LP might be associated with difference in clinical behavior of the two types of disease and role of these factors in premalignant behavior of OLP lesions.