A clinicopathological study of TRAIL expression in halo nevi

Pathogenesis of the halo phenomenon in halo nevus (HN) is not completely understood. Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) is implicated in the causation of immune and inflammatory cutaneous disorders such as vitiligo. To evaluate the clinicopathological characteristics and the expression of TRAIL in HN, we analyzed clinicopathological data of 32 patients with HN and performed immunohistochemistry for TRAIL and CD8 on HN (n = 32) and melanocytic nevi of healthy controls (n = 10). Correlation of TRAIL expression with clinicopathological features was assessed. We also performed double immunofluorescence staining for TRAIL and CD8 to confirm their co-localization. A variable degree of inflammatory cell-infiltrate around the melanocytic nevus was observed in all cases. Immunohistochemical staining showed a significantly higher expression of TRAIL in HN lesions as compared to that in skin of healthy controls. The shorter the evolution time of HN, the stronger was the TRAIL expression. TRAIL had a positive association with the CD8+ T cells infiltrate. Co-localization of TRAIL in the CD8+ cells in HN was observed on double immunofluorescence. According to its abundant expression in HN lesions and close association with the disease course and predominant CD8+ inflammatory cells, it seems that TRAIL involves in the pathogenesis of HN.