Disturbance of DNA-Synthesis in early psoriasis.

In earlier studies we have shown that there is a significant prolongation of DNA-synthesis time (ts) in the epidermal cells of fully developed psoriatic lesions. The present study shows that this prolongation is to be observed even in very early plaques. The prolongation of ts precedes the development of acanthosis. A dermal infiltrate with increased proliferative activity seems to be a stimulus, in the sense of a Koebner-phenomenon. There is no pronounced prolongation of ts in other acute or chronic inflammatory processes of the skin. The behaviour of the infiltrate in psoriasis is similar to that in allergic patch test reaction. However, the abnormal psoriatic epidermis, with disturbed DNA-synthesis, does not react to the above mentioned infiltrate with a limited hyperproliferation but with the development of a psoriatic plaque. There is obviously congenital disturbances of metabolism within the epidermal cells in psoriasis.