DNA-SYNTHESIS OF PSORIATIC EPIDERMIS

Tissue specimens of psoriatic skin were incubated in the presence of tritiated Thymidine for 30 min and compared with noninvolved skin. The autoradiographed sections showed a decreased number of silver grains per labelled nucleus in the psoriatic epidermis, however, the labelling index of the basal layer was not altered. The findings indicate a reduced rate of DNA synthesis, so that the DNA synthesis phase as well as the generation time of the intermitotic basal cells in psoriasis are prolonged. Although in psoriasis therefore it takes longer for the individual basal cell to be ready for the next division, the increased epidermal proliferation can still be explained by the greatly augmented number of dividing cells per unit skin surface. © 1969 Springer-Verlag.