Background  Lichen planus (LP) is an inflammatory disease of the skin and oral mucosa. The association of LP and chronic hepatitis C virus (HCV) is well established, with variable prevalence rates among different populations. Toll-like receptors (TLRs) are key regulators of both the innate response and the adaptive response. However, TLRs also interact with endogenous ligands released by necrotic cells, and this process can intensify autoimmune diseases such as rheumatoid arthritis and systemic lupus erythematosus.

Objective  To investigate the role of Toll-like receptor-7 (TLR-7) in LP through the detection of TLR-7 protein, and to compare between the expression of TLR-7 protein in HCV-positive and HCV-negative patients with LP.

Materials and methods  The study included 20 skin biopsies from patients with LP and 10 control biopsies. TLR-7 protein was detected by Western blot analysis. Detection of HCV-specific antibodies in the patient serum was done using ELISA technique.

Results  Our analysis revealed a significantly lower level of TLR-7 protein in all the LP skin biopsies compared with controls. The expression showed no difference between HCV-positive and HCV-negative patients.

Conclusion  We concluded that TLR-7 abnormal expression in LP may have an impact on the pathogenesis of the disease. TLR-7 receptor and HCV relationship in patients with LP could not be confirmed by this study.