comparison between DNA synthesis and mitosis in uninvolved and involved psoriatic epidermis and normal epidermis

Biopsies have been taken from the involved and uninvolved skin of eleven patients with psoriasis and the normal skin of six patients without psoriasis, 1 h after in vivo injection of 10 μCi of ³H-thymidine. Mitotic counts and counts of labelled cells (synesizing DNA) after autoradiography have been carried out. The ratio of mitoses to labelled cells was 1: 25 in clinical psoriasis, 1: 190 in uninvolved psoriatic epidermis and 1: 450 in normal epidermis. The number of labelled cells in clinical psoriasis was approximately 12 times greater than normal epidermis. However, the number of labelled cells in uninvolved psoriatic epidermis was approximately twice that of normal. These results imply an alteration in the components of the cell cycle in both involved and uninvolved psoriatic epidermis.