Direct injection of naked DNA and cytokine transgene expression: implications for keratinocyte gene therapy

Intradermally injected DNA diffuses into the epidermis and can then enter keratinocytes and become expressed by these cells. Using this method, plasmids containing cytokine genes that have been introduced into keratinocytes can induce a level of cytokine expression sufficient to provide biological effects in the treated skin. Furthermore, transgenic cytokines released from the transduced keratinocytes can also enter the circulation and have downstream effects on other target organs. Thus far, naked DNA injection appears to be a safe, simple, and relatively efficient method that enables genes to be expressed in transplanted human skin on immunosuppressed animals. In humans, keratinocyte gene therapy using the cytokine gene DNA injection method has the potential to become a powerful therapeutic tool for dermatologists in the management of certain inflammatory and other dermatoses.