Vitiligo Autoantigen VIT75 Is Identified as Lamin A in Vitiligo by Serological Proteome Analysis Based on Mass Spectrometry

VIT75 is a 75-kDa melanocyte membrane antigen (Ag) that had been observed, but not identified until now. Its immunopathogenic role in vitiligo remains unknown. In this study, serological proteome analysis based on mass spectrometry was employed to identify VIT75. Three disparate 75-, 60-, and 45-kDa proteins on two-dimensional (2D) gel were, respectively, identified as lamin A, tyrosinase-related protein 1, and melanin-concentrating hormone receptor 1. The latter two proteins are well-known Ags. Immunoreactivity analysis showed that the 75-kDa protein displayed on the 2D gel was recognized by human anti-lamin A IgG. Antibody (Ab) reactivity to lamin A was positive in 28.6% of patients' sera. Only 3.1% healthy sera reacted with the lamin A. A total of 91.7% of the positive sera was from the active non-segmental vitiligo (NSV). The positive rate and mean titer of anti-lamin A Ab are higher for NSV with autoimmune disease than for NSV without autoimmune disease. These data demonstrate that VIT75 is lamin A. To our knowledge, this is a previously unreported vitiligo Ag. Anti-lamin A Ab may be a potential marker of NSV with autoimmune disease. The study indicates that the targets of autoantibodies in vitiligo patients can be revealed by serological proteome analysis.