Patients affected by vitiligo and autoimmune diseases do not show antibodies interfering with the activity of the melanocortin 1 receptor

Background : Vitiligo is an acquired depigmenting disorder characterized by the loss of melanocytes from the epidermis with the development of white patches in various distribution. The pathogenesis of vitiligo is still unknown, but the association with autoimmune disorders and organ specific autoantibodies, supports the hypothesis of an autoimmune pathogenesis. Aim : The aim of the present study was to investigate if autoantibodies present in sera of patients affected by vitiligo may be able to interfere with the activity of the αMSH on the melanocortin 1 receptor (MC1R). Materials/Subjects and methods : IgG from the sera of 41 patients with vitiligo associated or not with thyroid autoimmune diseases or other autoimmune pathologies were incubated with HBL20 cells (human malignant melanocytes expressing the MC1R) in the presence of a sub-maximal dose of αMSH. A normal IgG range was determined by using IgG extracted from 30 control sera of normal subjects. Results : None of the IgG from vitiligo patients was able to inhibit αMSH-stimulated cAMP production in HBL20 cells. Conclusions : Autoantibodies against MC1R are rare or absent in sera of vitiligo patients.