Previous studies revealed that sera of patients with cutaneous melanoma-associated retinopathy (MAR) specifically reacted with bipolar cells of the re-tina. However, the specific bipolar cell antigen has not yet been identified. To identify the bipolar cell MAR antigen, we performed an immunological in-vestigation using serum from MAR patients. In western blot analysis, retinal 33kDa protein was probed commonly with sera from MAR patients, while such immunoreactivity was not detected from patients with malignant melano-ma without retinopathy. This data strongly suggests that a novel retinal 33kDa protein may act as an autoantigen of MAR
