Expression of TLR9 and its mRNA in the lesions of lichen planus

To investigate the role of toll-like receptor 9 (TLR9) in the pathogenesis of lichen planus, the expressions of TLR9 and its mRNA in the lesional skin of lichen planus were detected by immunohistochemical technique (SP) and RT-PCR. As control, normal skin of healthy volunteers was also tested. The immunohistochemical study showed that the expression of TLR9 in the lesional skin of lichen planus was significantly higher than that in the normal controls. The results of RT-PCR showed that both skin lesions and normal controls had TLR9 expression. In skin lesions, the expression level of TLR9 mRNA was 1.6075+/-0.0930, which was significantly higher than that in normal controls (P<0.001). These findings indicated that up-regulated expression of TLR9 and its mRNA might be involved in the pathogenesis of lichen planus.