Interleukin-8 immunoreactivity in epidermis of cutaneous T-cell lymphoma patients

The histopathologic hallmark of cutaneous T-cell lymphoma is collections of malignant T cells in the epidermis. The mechanism(s) involved in the T-cell localization is unknown, however recent evidence suggests that cytokines play a role. Since Interleukin-8 functions both as a leukocyte and lymphocyte chemoattractant, we measured IL-8 expression in skin of cutaneous T-cell lymphoma patients. Lesional skin was obtained by biopsy from cutaneous T-cell lymphoma (CTCL) patients and patients suffering from other dermatoses and subjected to in situ hybridization with a 35S-Riboprobe and immunofluorescence to detect IL-8. Fourteen out of 15 lesional biopsies from histologically proven CTCL patients displayed intense epidermal IL-8 immunoreactivity compared to negligible reactivity in sections from 14 normal patients and other inflammatory dermatoses. These results were corroborated by strong hybridization signals using IL-8 probes in only the lesional CTCL skin. Lesional CTCL epidermis contains elevated levels of IL-8 mRNA and protein suggesting a role for this cytokine in the pathogenesis of the disease.