[Anti-epidermal cytotoxic reactions in the effector stage of lichen ruber planus].

Immunohistochemical investigations on skin lesions of lichen ruber planus indicate HLA-DR-expression by keratinocytes, Langerhans cells (LC), and infiltrated mononuclear cells. In the early stage of this condition, the lymphocytic infiltrate consists of a considerable part of (CD8+) cytotoxic/suppressor- and (LGL+) natural killer cells. Evidently, the cytotoxic potential of these lymphocyte subpopulations is directed against basal keratinocytes and epidermal LC. As a result of cytotoxic/cytolytic activities, non-cell associated CD 1-reactivity accumulates in the dermoepidermal junction zone, thus indicating damaged LC.