Abstract: In order to study the status of cell apoptosis in psoriatic epidermis, we have investigated the changes of the lesions in various stages in patients with psoriasis vulgaris by using terminal deoxynueleotidyl transferase-mediation dUTP-biotin nick end labelling (TUNEL). The results showed that the highest frequency of apoptotic keratinocytes was observed in the early scaling papular lesions, and the frequency was reduced in the progressive maculo-papular lesions and the coalescent plaques successively. The frequency of hyperproliferation of epidermis was in the reverse order in comparison with the above results. These results suggest that increased apoptosis of keratinocytes is the initial change of psoriatic epidermis, then hyperproliferation of keratinoeytes follows.

Key words: Psoriasis, Keratinocyte, Apoptosis