Survival of allogeneic cells in cultured organotypic skin grafts

Organotypic cultures of human skin were made using dermal fibroblasts seeded into a type I collagen gel overlaid with epidermal keratinocytes. Full-thickness excision of tattoos was performed on five patients, three of whom received sex-mismatched allografts. Patients were not immunosuppressed. Biopsies were obtained up to 3.5 years later. In situ hybridization of the PHY2.1 repetitive Y chromosome sequence revealed male fibroblasts and keratinocytes at 11 weeks and 2.5 years in the two female patients grafted with male cells. Structural components in the dermal substitute matured with time, and elastic fibers formed an interlacing meshwork by 18 months. Electron microscopy of the dermal-epidermal junction of an organotypic allograft revealed anchoring fibrils that had normal features at this time. Hyperemia of early grafts settled and contour correction was maintained, while repigmentation was variable. Hypertrophic scars did not occur, and graft contracture was never more than 20 percent. We conclude that this organotypic skin graft shows potential toward the goal of allogeneic skin replacement in a one-step procedure.