[Mononuclear epithelial infiltration in squamous cell skin cancer, allergic contact dermatitis and skin allograft].

Histological and electron microscopic examinations of cellular infiltration were carried out in squamous cell carcinoma of the skin in humans, in the zone of dinitrochlorobenzene allergic contact dermatitis in guinea pigs, and in allotransplant and the surrounding skin in mice. In all the processes studied, the epithelial part of the cell infiltration area was found to differ from the connective tissue area by cell composition. The epithelial sheets were shown to be infiltrated mostly with heterogenous lymphocytes as well as occasional macrophages forming simple and slit-like contacts with epithelial cells. It is doubtful whether lymphocyte-macrophage infiltration of the epithelium causes necrobiotic changes in its cells in the processes studied.