Immune Response to Specific Molecules of the Retina in Proliferative Vitreoretinal Disorders

In recent years, several reports have contributed to a growing suspicion that there is immunologic involvement in proliferative intraocular disorders such as proliferative vitreoretinopathy and proliferative diabetic retinopathy. Immune privilege, as in the brain, ovary and testis, also exists in the eye. Therefore, immune responses to unique molecules of the eye, e.g. retinal S-antigen (S-Ag), which the immune system never learns to regard as "self", are possible. This study describes the presence of S-Ag, a major soluble photoreceptor protein involved in the visual transduction cascade, in pathological vitreous. We employed indirect immunoblotting, with human retina as substrate, and demonstrated the occurrence of antiretinal antibodies in the sera of a series of patients with proliferative vitreoretinal disorders. Immunoblot analysis of physiological retina and lyophilized S-Ag, revealed this protein as a target molecule of the immunological involvement of the retina. Further immunochemical investigation, however, must clarify whether this autoimmune reaction is the cause, a consequence, or an aggravating factor of the disease. As we come to understand the cellular and molecular mechanism, a new generation of therapeutic strategies may be envisioned.