Uninvolved skin from psoriatic patients develops signs of involved psoriatic skin after being grafted onto nude mice.

Clinically involved psoriatic epidermis maintains its histological appearance, increased labeling index, and increased level of plasminogen activator after being grafted onto athymic nude mice. Uninvolved psoriatic epidermis develops increases in plasminogen activator activity after being grafted onto athymic nude mice; this is accompanied by an increased labeling index. Thus, psoriatic skin can develop markers of psoriasis independent of the host.