Most studies have failed to identify a specific antimelanocyte antibody in the serum of patients with vitiligo.1-3 Only recently, Hertz et al4 described two patients with vitiligo and polyendocrine deficiencies who had evidence for an autoantibody that binds to melanin-producing cells (MPC) in human skin, nevi, and melanomas. They stated that other investigators1,2 probably failed to identify this antibody because patients who were known antibody-formers were not selected, and only a conventional indirect immunofluorescence technique (IIT) was used. We have retested the serum of two patients with vitiligo and "autoimmune polyendocrine diseases" who had been described previously.2 Patients and Methods Patient 1 is a 25-year-old woman with vitiligo, chronic idiopathic hypoparathyroidism, Addison's disease, chronic candidiasis, and atrophic gastritis with thyroid microsomal, gastric parietal cells, adrenal cortex, pancreatic islet cell, and prolactinsecreting cell autoantibodies. Patient 2 is a 57-year-old man with vitiligo, Hashimoto's thyroiditis, atrophic gastritis, and