Intralesional interferon alfa-2b in the treatment of basal cell carcinoma. Immunohistochemical study on cellular immune reaction leading to tumor regression.

Abstract

Four patients with basal cell carcinomas were treated with intralesional injections of interferon alfa-2b (1.5 million IU per injection) three times a week for 2 weeks. Histopathologic examination of biopsy specimens of the lesions confirmed the absence of basal cell carcinoma in all cases 4 weeks after completion of therapy. A dense mononuclear cell infiltrate and numerous ectatic blood vessels were present in the dermis at the sites of previous basal cell carcinoma. Immunohistologic analysis of the dermal infiltrate revealed a marked increase of Leu-4+ T cells with a slight predominance of Leu-3+ helper/inducer T cells over Leu-2+ suppressor/cytotoxic T cells. Most of the dermal infiltrate expressed HLA-DR antigen. In addition, Leu-11+ natural killer cells were observed in the dermal infiltrate. Immunohistologic changes in the skin lesions at the sites of previous basal cell carcinoma suggest that intralesional interferon alfa-2b acts on tumor cells by enhancement of local T-cell-mediated immune responses.