Study of the DNA content of basal and suprabasal keratinocytes in psoriatic patients.

We carried out a cytophotometric study of the DNA content of basal and suprabasal keratinocytes using involved and uninvolved histological sections of epidermis from psoriatic patients using the Feulgen technique. The reference 2C value of the DNA content was obtained from lymphocyte nuclei in a sub-epidermal infiltrate from normal skin. According to the DNA content profiles obtained for the keratinocytes of psoriatic patients, individuals were classified into three groups: Group 1, composed of individuals with a monomodal diploid profile and preferential keratinocytes with a 2C DNA content and, hence, a low proliferation activity; Group 2, consisting of patients with significantly increased 2C-4C and 4C populations; and Group 3, made up of individuals with high proportions of 4C and hyperdiploid (6C, 8C, and > 8C) keratinocytes. The results obtained in this work and the observed changes in the proliferative activity of the keratinocytes in the three groups of patients led us to suggest that the cytophotometric determination of the DNA content of basal and suprabasal keratinocytes may be useful as a prognostic criterion for the classification of psoriatic patients in terms of the extent of alteration of their proliferative epidermal activity.