Blistering by histological location Intra-epidermal blistering 2021-05-08T14:57:59Z A type of blistering in which the lesions are located within the epidermis with loss of cell-cell adhesion of keratinocytes. In simplex EB, cleavage occurs in the basal layer, which is the innermost layer of the epidermis and consists of a single layer of basal germinative cells (mostly epidermal Keratinocytes) that proliferate and thereby produce new cells for other epidermal layers. As the cells move towards the upper layers of the epidermis they mature and eventually form cornified cells. The suprabasal cell layer lies directly above the basal layer and is composed of five to ten layers of cells.