TYROSINASE AS AN AUTOANTIGEN INPATIENTS WITH VITILIGO

Vitiligo is considered an autoimmune disorder due to the generation an d presence of autoantibodies directed against melanocyte antigens in t he patients' sera. In the present study we point towards a newly defin ed autoantigen in vitiligo, the enzyme tyrosinase, which participates in the process oi. melanogenesis. Anti-tyrosinase antibodies were dete cted in the sera of seven patients with diffuse and 11 patients with l ocalized vitiligo. Employing solid-phase ELISA to mushroom tyrosinase, we found that patients with diffuse vitiligo had significantly higher titres of IgG anti-tyrosinase autoantibodies than patients with local ized disease or healthy subjects. These anti-tyrosinase autoantibodies have relatively high functional affinity to tyrosinase and can be rec overed from vitiligo patients' sera by affinity purification. The anti -tyrosinase antibodies do not cross-react with other enzymes recognize d as autoantigens in different autoimmune disorders and the autoantibo dies do not block the enzymatic activity of tyrosinase, indicating tha t they are not reacting with the catalytic site of the enzyme. These d ata point to tyrosinase as an autoantigen in vitiligo and suggest that anti-tyrosinase titres call serve as a marker for disease activity.