 A shaved biopsy specimen about 1 cm2 is taken from the patients normally pigmented area under local anesthesia lidocaine hydrochloride 20 mgml. The specimens are incubated in 0.25 trypsin solution for 15 minutes at 37C 0.02 EDTA solution for 10 minutes. Then epidermal sheets are gently manipulated with forceps to dissociate the epidermal cells and to yield a cell suspension, followed by treatment with 0.5 trypsinversene solution at 37C for 3-5 minutes. Well-dispersed cell suspension is aspirated into 1 ml syringes and injected directly in epidermis. 