Plasminogen activation in psoriasis

Plasminogen activation is a widely documented physiological phenomenon in which plasminogen activators (mainly urokinase and tissue type plasminogen activator) transform the zymogen plasminogen into the wide-spectrum proteinase plasmin. We show here that psoriatic epidermis is provided with abnormal plasminogen activator activity, mainly dependent on the activity of tissue type plasminogen activator and that this abnormal activity can be reversed with common topical treatments (i.e. anthralin, and 0.1% betamethasone valerate cream). We also report abnormal immunohistochemical localization of plasminogen, urokinase and tissue type plasminogen activator in psoriatic epidermis which returned to normal after the topical treatments. These data suggest a major role of plasminogen activation in the pathogenesis of psoriasis.