Immunopathological changes in the skin following recombinant interleukin-2 treatment

The systemic administration of the cytokine recombinant interleukin-2 (rIL-2) is associated with a number of toxic effects, including dermatological complications. The clinical, histological, and immunopathological changes occurring in the skin of six patients receiving rIL-2 for metastatic colorectal carcinoma have been studied. All of the patients developed a diffuse erythema shortly after initiation of the treatment. In one patient, generalized erythroderma and photosensitivity developed. The initial biopsy revealed patchy spongiosis, focal exocytosis, and focal basal layer damage with a perivascular chronic inflammatory cell infiltrate. With further treatment there was progressive thickening of the epidermis. Immunohistochemistry revealed changes in the expression of CD1, CD3, CD4, and CD25, particularly on perivascular cells. Additionally, there was an increase in the expression of intercellular adhesion molecule-1 (ICAM-1) on keratinocytes in the basal and mid-layers of the epidermis, endothelial cells, and perivascular cells. It is hypothesized that the expression of ICAM-1 by the epidermal keratinocytes may be the important event in initiating the cutaneous manifestations associated with rIL-2 administration.