Abstract: The skin biopsies from thirty patients with psoriasis and fifteen normal controls were examined for-interferon (IFN-γ) by using murine monoclonal antibodies against human IFN-γ, immunohistochemical technique (APAAP method) and microspectrophotometry. Our results showed that the staining for IFN-γ could be detected in the epidermis as well as in the dermis of all the psoriatic lesions, with more intense staining and wider distribution in lesional epidermis than in lesional dermis. IFN-γ was observed in the intercellular spaces of the keratinocytes in the upper and mid layers of epidermis, but not in stratum basale and first 1-3 cell rows of stratum spinosum. The IFN-γ levels were increased in the lesional epidermis of active stage and decreased in the stationary stage. No positive staining was found in the skin of the normal controls.

Key words: Interferon, type Ⅱ, Psoriasis