Demonstration of giant and anular nexus in the psoriatic epidermis.

In the psoriatic skin, nexus were most prominent in the upper layers of the viable epidermis, using the Alcian blue-Lanthanum technique. There, they reached double and manifold the length (giant nexus) of those in normal epidermis. According to the villous transformation of the epidermal cell surface in psoriasis, the nexus showed a great variation in their shape. Undulating nexus were seen beside invagination--and anular nexus. On ther other hand, nexus were lacking in the deepest layers of the psoriatic epidermis in contrast to normal epidermis. From these findings it seems that the intercellular communication by specialized low resistant junctions is reduced in the deepest layers of the psoriatic epidermis. In the upper epidermal layers, however, the extensive formation and the variable configuration of the nexus express a high synthetic activity and a well developed intercellular information in these areas of the psoriatic epidermis.