In situ expression and serum levels of tumour necrosis factor alpha receptors in patients with lichen planus.

In lichen planus (LP), an inflammatory skin disease of unknown origin, adhesion molecules and their ligands combined with the local and systemic release of various cytokines are fundamental in regulating inflammation. Therefore, we investigated the expression of tumour necrosis factor alpha receptor (TNF-R) I and II in lesional skin of 15 patients suffering from acute eruptive LP by means of immunohistochemistry. In addition, the serum levels of their soluble forms (sTNF-R) were measured by enzyme-linked immunosorbent assay (ELISA), compared with those of healthy volunteers (n = 10) and correlated with the in situ inflammatory response. In contrast to healthy controls, LP patients showed significantly increased serum levels of sTNF-RI as well as sTNF-RII (p < 0.02). These enhanced serum titres were correlated with a prominent expression of TNF-RI on lesional keratinocytes (basal > suprabasal) and of both receptors on skin-infiltrating lymphocytes. Our data suggest an important role of the TNF ligand/receptor interactions in the induction and/or perpetuation of the pathogenetical and apoptotic events in LP.