Stimulated human melanocytes express and release interleukin-8, which is inhibited by luteolin: relevance to early vitiligo

Vitiligo is a disorder of depigmentation, for which the pathogenesis is as yet unclear. Interleukin (IL)-8 (CXCL8) is a key inflammatory chemokine. We investigated the regulation of IL-8 production in human melanocytes, and the IL-8 serum levels and skin gene expression in patients with vitiligo and in controls. Cultured melanocytes were stimulated for 24h with tumour necrosis factor (TNF) 100ng/mL and IL-1 10ng/mL, with or without pretreatment with luteolin 50mol/L for 30min, and IL-8 release was measured by ELISA. Serum cytokines were measured by a microbead array. Skin biopsies were taken from healthy subjects (n=14) as well as from marginal lesional and nonlesional skin from patients with vitiligo (n=15). IL-8 gene expression was evaluated by quantitative real time PCR. Both TNF and IL-1 stimulated significant IL-8 release (P<0.01) from melanocytes, whereas pretreatment with luteolin significantly inhibited this effect (P<0.01). IL-8 gene expression was significantly increased in vitiligo compared with control skin (P<0.05). IL-8 may be involved in vitiligo inflammation. Inhibition by luteolin of IL-8 release could be useful for vitiligo therapy.