Activation of nuclear factor-kappa B correlates with tumor necrosis factor-alpha in oral lichen planus: a clinicopathologic study in atrophic-erosive and reticular form.

BACKGROUND: Nuclear factor-kappa B (NF-kappaB) is believed to be involved in the pathogenesis of various inflammatory diseases, including oral lichen planus (OLP). The objective of the present study was to investigate the possible relationship between NF-kappaB activation and expression of tumor necrosis factor-alpha (TNF-alpha) in OLP and their expression pattern in relation to several clinical features.
METHODS: Thirty OLP cases were divided into atrophic-erosive form (14 cases) and reticular form (16 cases) according to their clinical manifestations. The expression of NF-kappaB p65 and TNF-alpha of both two groups were investigated by immunohistochemical staining, and the percentage of positive cells was calculated in each case. Biopsies of 10 normal oral mucosa (NOM) also underwent the same procedure as controls.
RESULTS: Nuclear factor-kappa B p65 nuclear staining was found in nuclei of basal and suprabasal epithelial keratinocytes in OLP, however, no positive staining was found in NOM. Positive TNF-alpha staining was detected in cytoplasm of basal epithelial keratinocytes in OLP, and only scattered staining was detected in NOM. Expression of NF-kappaB p65 and TNF-alpha were significantly different with respect to clinical forms and lesion sites (P < 0.05), except for genders (P > 0.05) in 30 OLP cases. NF-kappaB nuclear staining positively correlated (r = 0.676, P < 0.01) with TNF-alpha overexpression in OLP.
CONCLUSIONS: Nuclear factor-kappa B activation and its correlation with overexpression of TNF-alpha may play an important role in pathogenesis of OLP. There might be a positive regulatory loop between NF-kappaB and TNF-alpha, which may contribute to inflammation in OLP; NF-kappaB may also protect epithelial keratinocytes from excessive apoptosis.