Cell-mediated immunity to retinal antigens in patients with pigmentary retinal degenerations.

Twenty patients with pigmentary retinal degenerations of various types, nine patients with other ocular and systemic illnesses, and five normal volunteer subjects were tested for cellmediated immunity by the I-iododeoxyuridine (IUDR) cytotoxicity assay, against a longterm tissue culture line derived from retinoblastoma, which by electron microscopy showed evidence of being derived from photoreceptor elements; and against control tissue culture lines derived from ocular melanoma and breast carcinoma. Seventeen of 20 patients with retinal pigment degenerations showed significantly more cytotoxicity than the other subjects only against the retinoblastoma cell line. It seemed likely that the observed reactions were against normal retinal antigens in the tumor cell line. This finding of cell-mediated immunity in patients with benign retinal disease is consistent with animal experiments showing that parts of the retina are antigenic, and suggests that cellular immune processes may play a role in the pathogenesis or pathophysiology of pigmentary retinal degenerations.