THE ROLE OF TYROSINASE IN AUTOIMMUNE VITILIGO

Vitiligo is a common depigmenting skin disease, associated with certai n autoimmune endocrinopathies, and autoantibodies to several antigens can be found in melanoma cells. We set out to identify the antigens. W e examined 26 patients with vitiligo and associated endocrine disease. Of these, 18 patients (77%) and 8 immediate family members had autoan tibodies specific for a 69 kDa protein in HTB-70 human melanoma cells that was not seen in control cells. The autoantibody-positive patient sera reacted with recombinant human tyrosinase expressed in Escherichi a cell seen by western blots, as did antibodies raised in rabbits agai nst hamster tyrosinase, but not to recombinant tyrosinase-related prot ein. Not one of 31 normal controls or 8 patients with alopecia or syst emic lupus erythematosus had tyrosinase autoantibodies but a small pro portion (12%) of 42 patients with autoimmune endocrine disease without a history of vitiligo had them. The results show that tyrosinase, an enzyme important in melanin formation, is a principal autoantigen of a utoimmune vitiligo.