Cultured epidermal autografts from clinically revertant skin as a potential wound treatment for recessive dystrophic epidermolysis bullosa.

Inherited skin disorders have been recently reported to have sporadic normal-looking areas, where a portion of the keratinocytes have recovered from causative gene mutations (revertant mosaicism, or "RM"). We observed a case of recessive dystrophic epidermolysis bullosa (RDEB) treated with cultured epidermal autografts (CEAs), whose CEA-grafted site remained epithelized for 16 years. We proved that the CEA product and the grafted area included cells with RM. Based on these findings, we conducted an investigator-initiated clinical trial of CEAs from clinically revertant skin for RDEB. The donor sites were analyzed by genetic analysis, immunofluorescence, electron microscopy and quantification of the reverted mRNA with deep sequencing. The primary endpoint was the ulcer epithelization rate per patient at 4 weeks after the last CEA application. Three RDEB patients with 8 ulcers were enrolled, and the epithelization rate for each patient at the primary endpoint was 87.7%, 100% and 57.0%, respectively. The clinical effects were found to persist for at least 76 weekCEA transplantation. One of the three patients had apparent RM in the donor skin and in the post-transplanted area. CEAs from clinically normal skin are a potentially well-tolerated treatment for RDEB.