Vitiligo autoantibodies are effective against melanoma.

Vitiligo is a dermatologic disease characterized by local, dispersed, or diffuse white patches on the skin. The disease is defined as an autoimmune disorder because autoantibodies against membranal components of melanocytes are found in the patients' sera. The current study examined whether the autoantibodies reacting with the normal melanocytes could be a potent therapy against melanoma cells. The three in vitro assays used to determine the antibody reactivities using a mouse melanoma cell line B-16-F10 and M-14 human melanoma cells as targets are as follows: enzyme-linked immunosorbent assay (ELISA), proliferation assay, and morphologic examination in the presence of antibodies purified from sera of patients with vitiligo. In the in vivo studies, experimental melanoma was intravenously induced in C57BL/6J mice, and the mice were treated by daily intraperitoneal injections with purified immunoglobulin G (IgG) fraction derived either from patients with vitiligo or from healthy subjects. The binding of IgG derived from patients with vitiligo was demonstrated by ELISA: Exposure of melanoma cells to the vitiligo autoantibodies was followed by inhibition of their proliferation capacity. In addition, morphologic alterations exemplified by detachment of the cells from their solid support associated with melanin release were observed in the B-16-F10 cells. Less metastatic foci developed in the lungs of the mice treated with the purified IgG fraction from the sera of patients with vitiligo compared with those treated with purified IgG fraction from healthy subjects. The results of this study point to the presence of anti-melanoma autoantibodies in the sera of patients with localized and diffuse vitiligo. These antibodies have a destructive effect on melanoma cells in vitro and in vivo.