Mehdi Tavassoli

54 patients with localized or primary malignant melanoma had circulating cytoplasmic antibody. A few patients formerly positive but who had converted to negative, and some who on clinical grounds had a primary lesion but who had negative tests for cytoplasmic antibody, were found to have developed metastatic lesions. It is postulated that the halo naevus represents a seldom seen interim stage natural protective mechanism-that is, a rejection phenomenon of malignant melanoma. It is the visualization, so to speak, of the surveillance system normally so effective in preventing malignant melanoma from developing in every individual. The study of such aspects in the behaviour of moles and melanomas raises the question not only why are halo naevi spontaneously rejected and heal, but why do malignant melanomas develop and persist in patients who in all other respects appear to have normal and intact immunological mechanisms.-We are, etc.,