MELANOMA-ASSOCIATED HYPOPIGMENTATION - WHERE ARE THE ANTIBODIES

Antibodies to the B16 melanoma cell line and to tyrosinase have been r ecently defined in our laboratory in sera of patients with vitiligo, m elanoma, melanoma-associated hypopigmentation (MAH), and in healthy su bjects. The antibody titers in each subject were measured by enzyme-li nked immunosorbent assay, were compared with the mean optical density (OD) of the control group, and were expressed as relative OD. The tite rs of anti-B16 antibodies (relative OD +/- standard error) were 1.000 (0.058) in the controls, 1.025 (0.077) in patients with metastatic mel anoma, 0.5862 (0.15) in MAH, 1.377 in surgery-induced MAH, 1.087 in va ccination with anti-idiotypic antibodies, and 2.098 (0.15) in autoimmu ne vitiligo. The titers in vitiligo were significantly higher (p < 0.0 001) than in MAH or in healthy controls. Antityrosinase antibodies wer e found in titers of 1.000 (0.1024) in the controls, 1.516 (0.225) in metastatic melanoma, 1.027 (0.180) in MAH, 1.075 in surgery-induced MA H, 2.308 in vaccination-induced MAH, and 4.536 in vitiligo. Difference s were found between vitiligo and MAH (p = 0.008), surgery-induced MAH (p = 0.009), vaccination-induced MAH (p = 0.059), and healthy subject s (p < 0.0001). The results of this study point to the cross-antigenic ity between melanocytes and melanoma cells, and to participation of an tibodies against melanoma-associated membrane antigens in the mechanis m leading to the development of MAH in patients with melanoma.