The effects of intralesional recombinant alpha-2 interferon(IFN) in the treatment of basal cell carcinoma(BCC) and actinic keratosis(AK) would be of value in selected patients.

Our purpose is to evaluate the differences of cellular immune reactions between the responded and the unresponded cases treated with IFN.

We treated five patients with BCC and two patients with AK with the intralesional injection of recombinant alpha-2 IFN. We performed immunohistochemical stainings with paraffin-embedded specimens from the pretreated and posttreated skin lesions.

Four patients(three with BCC and one with AK) were healed and three patients showed improvement after treatment. In immunohistochemical stainings, there was an increased number of T cells in the dermal infiltrate of the responded cases but not in the unresponded cases.

Intralesional IFN may induce T cell-mediated immune response at the site of the tumor by immune modulation.