Stereotyped Distribution of Proliferating Keratinocytes in Disorders Affecting the Epidermis

We used the technique of autoradiography after incorporation of tritiated thymidine (3H-TdR) to evaluate keratinocyte proliferation in basal, epibasal, and other epidermal layers in 30 diseases affecting the epidermis. The number and proportion of 3H-TdR-labeled keratinocytes were counted in the different layers of the epidermis. Significant correlations were found between the proliferative indices of the different epidermal layers. Such links indicate that the epidermis responds in a rather stereotyped way to various pathological conditions. There exists some regulation in the distribution, number, and proportion of 3H-TdR-labeled keratinocytes in the various layers of the epidermis.