Recovery processes during regression of plane warts.

The regressing process of plane warts can be divided into two phases: initial changes of wart virus-infected cells that later result in degeneration of warts, and recovery phase in which degenerating warts are rejected from the level of the basal layer followed by regeneration of normal epidermal cells from the surrounding epidermis. Electron microscopic observations of recovery phase of wart regression showed (1) the epidermal lesion was clearly divided into degenerating wart possessing altered viruses and regerating epidermis; (2) melanocytes were demonstrated in degenerating warts; and (3) a new granular layer was evident beneath regressing wart in late recovery. Throughout the recovery process, infiltration of lymphocytes and macrophages was observed only in regenerating epidermis.