CD69 EXPRESSION AND TUMOR-NECROSIS-FACTOR-ALPHA IMMUNOREACTIVITY IN THE INFLAMMATORY CELL INFILTRATE OF HALO NEVI

It has been suggested that the involution of the pigmented lesions of halo naevus (HN) is mediated by an immune response, with the involveme nt of specific cytotoxic T lymphocytes, To explore further the pathoge nesis of HN, skin biopsies from six patients with this condition were obtained and the characteristics of the infiltrating inflammatory cell s were studied by immunostaining techniques. We found that the cell in filtrate of HN is mainly composed by CD8(+) T lymphocytes that express the activation molecule CD69, Tumour necrosis factor-alpha (TNF-alpha ) immunoreactivity was detected on the inflammatory cells, a finding t hat suggests that the infiltrating T cells of HN are actively synthesi zing this cytokine. Our results indicate that the infiltrating cells o f HN predominantly have an activated cytotoxic phenotype, and suggest that these cells are indeed involved in the regression of the naevomel anocytic naevus of HN.