Humoral and cellular immune reactions against retinal antigens in clinical disease.
Autoimmune reactions against retinal antigens have been suggested to play an important role in clinical uveitis in man. As yet the evidence for this assertion is very weak. Sympathetic Ophthalmia is a disease entity which comes closest to acceptance as an autoimmune disease although the autoantigen involved has not been identified. Both cellular and humoral autoreactivity against retinal antigens have been found both in uveitis patients as well as in healthy controls. Very high levels of retinal antibodies were found in onchocerciasis patients but no relation was observed with the occurrence of chorioretinitis. Differences were observed when testing patient sera against human or bovine retinal antigens (S-antigen or IRBP) emphasizing the need for using human tissue when investigating autoimmune responses. Circumstantial evidence in favor of an autoimmune etiology of uveitis include the morphology of the inflammatory infiltrate, effect of immuno-suppressive therapy and especially the establishment of experimental animal models. The experimental models of S-antigen or IRBP induced uveitis are primarily T cell mediated and also show pineal gland involvement. As yet no "established" human autoimmune disease has been described with a dominant role for T cells. Furthermore there is no evidence for pineal gland involvement in clinical uveitis. Analysis of the specificity of the T cell infiltrate or deposited immunoglobulins obtained from the diseased tissues may provide conclusive evidence for a possible autoimmune character of certain clinical uveitis entities.