Experimental, cancer-induced retinopathy

Purpose: Vision loss occurring in association with cancers predominates in patients with small cell carcinoma of the lung (SCCL). The pathogenesis of some types of paraneoplastic retinopathy may be founded in autoimmunity, such as that previously proposed to explain the cause of the CAR syndrome, in which lung cancer cells expressing the CAR photoreceptor autoantigen, are considered the cause of the immune reaction which characterizes this form of cancer-induced blindness. An extended search for similar immunologic connections has uncovered a second example of this phenomenon, involving a cancer culture expressing a novel retinal antigen. This study inquired into the pathologic significance of the expression of this 'tumor-associated retinal antigen', as a possible trigger mechanism for the induction of autoimmune reactions affecting the eye. Methods: Cultures of SCCL (American Type Culture Collection) were evaluated for the expression of retinal antigens by propagation intraperitoneally in Lewis rats and evaluation of the induced immune response. Results: A culture of SCCL was found to be expressing a single retinal antigen, identified by the production of corresponding antibodies by the recipient rats in which the culture was introduced. Histologic examination of eyes of these rats revealed indications of retinal decay. Conclusions: Structural alterations to the retina can be induced experimentally in Lewis rats through the intraperitoneal cultivation of a SCCL recognized to be expressing a retinal antigen. This model of 'Experimental, Cancer Induced Blindness' provides further evidence of an autoimmune pathogenesis in certain forms of paraneoplastic retinopathy, demonstrating an immunologic pathway through which vision loss can occur as a remote effect of cancer, with eyesight declining as a result of a cancer-evoked autoimmune retinopathy.