Melanoma specific protein: occurrence in the urine of patients with halo naevus and vitiligo.

Melanoma specific protein is immunologically related to altered naevus cell cytoplasm. It is excreted by patients with malignant melanoma but in no other malignancy. The protein has been detected in patients with actively developing halo naevi but not when repigmentation is taking place. It also occurs in patients with very active vitiligo but in no other pigment condition we have studied. It is suggested that the protein is a marker of active destruction of naevus cells by immune mechanisms and that the release of toxic materials during this immune reaction may be responsible for the production of the halo phenomenon and for the areas of vitiligo that may be seen elsewhere on the skin.