Psoriasiform dermatosis in a rhesus monkey. Epidermal labeling indexes, polyamines, and histopathologic findings.

We have previously described the clinical and dermatopathologic features of a psoriasiform dermatosis in a rhesus monkey (Macaca mulatta). This animal has been studied further in attempts to characterize its skin disease. Epidermal cell DNA synthesis was measured following the intradermal injection of tritiated thymidine. Epidermal cell labeling indexes in the involved and uninvolved skin of the affected monkey and in the skin of a normal monkey were compared. The labeling indexes in the involved skin were significantly increased as compared with uninvolved skin; they were also significantly higher than in normal skin. Epidermal polyamine assays showed increased epidermal putrescine in involved skin together with increased spermidine and an increased spermidine-spermine ratio compared with uninvolved and normal skin sites.