Narrow‐band UVB irradiation stimulates the migration and functional development of vitiligo‐IgG antibodies‐treated pigment cells

Abstract

The pathogenesis of vitiligo remains unclear. Most authorities favoured the autoimmune cause for the strong associations of vitiligo with multiple autoimmune diseases and the presence of autoantibodies in vitiligo patients. Narrow-band UVB (NBUVB) irradiation has been considered to be an effective treatment for vitiligo with simple treatment procedure and decreased accumulated ultraviolet exposure doses. The aim this study was to investigate the effects of NBUVB irradiation on normal IgG antibodies (N-IgG) or vitiligo IgG antibodies (V-IgG)-treated NCCmelan5 cells in terms of proliferation, migration and melanin formation. Cultured NCCmelan5 cells were treated with (i) NBUVB irradiation alone, (ii) N-IgG or V-IgG alone, and (iii) combination of N-IgG or V-IgG with NBUVB irradiation. The proliferation of NCCmelan5 cells were evaluated using BrdU incorporation assay. Western blotting was used to determine the expressions of phosphorylated p125(FAK) (pp125(FAK)) and tyrosinase in NCCmelan5 cells. The locomotion of NCCmelan5 cells was assessed using time-lapse assay and in vitro wound scratch assay. Neither N-IgG nor V-IgG significantly affected the proliferation of NCCmelan5 cells. The migration, melanin formation and tyrosinase expression in NCCmelan5 cells were decreased by V-IgG. NBUVB irradiation increased the proliferation of V-IgG treated NCCmelan5 cells. In addition, NBUVB irradiation enhanced the mobility of V-IgG-treated NCCmelan5 cells via upregulation of pp125(FAK). The melanogenesis and tyrosinase expression in V-IgG-treated NCCmelan5 cells were promoted using NBUVB irradiation. Our study demonstrated that the deleterious effects of V-IgG in the pathogenesis of vitiligo might be overcome by NBUVB irradiation.