Tumour-specific antibodies in human malignant melanoma and their relationship to the extent of the disease.

Biopsy specimens and sera were obtained from 103 melanoma patients. Autoantibodies were demonstrated by (1) complement-dependent cytotoxicity of autologous melanoma cells in short-term culture; (2) complement-dependent inhibition of ribonucleic acid synthesis; (3) immunofluorescent staining of the cytoplasm of killed melanoma cells and of the surface membrane of viable melanoma cells. Over one-third of the sera studied had antibodies to autologous melanoma cells. Although for technical reasons all three tests could not be performed with the cells from every melanoma, whenever multiple testing was possible there was complete concordance. The autoantibodies were virtually confined to patients in whom the disease was not widely disseminated, and over 80% of such patients had positive sera. In a limited number of patients who have been followed autoantibodies disappeared as the disease progressed to become widely disseminated. Two patients with generalized disease developed autoantibodies following inoculation by their own irradiated tumour cells.TWO TYPES OF AUTOANTIBODIES WERE RECOGNIZED: one, active against antigen(s) in the cell surface membrane, was specific for each tumour-that is, only the autologous serum reacted-and was concerned in the cytotoxic activity; the other reacted with cytoplasmic antigens which appeared to be present in most or all melanoma cells.