Clinical Features of Autoimmune Retinopathy Associated With Anti-Retinal Antibodies

Abstract

Purpose:: Autoimmune retinopathies are a group of acquired disorders characterized by acute or subacute visual loss in adults, visual field changes and electrophysiologic abnormalities. The identification of antibodies directed against specific retinal antigens such as recoverin, enolase, or Tubby-like protein 1 (TULP-1) is supportive of an autoimmune retinopathy; however clinical suspicion may remain despite a negative test. We describe the clinical features of autoimmune retinopathy associated with anti-retinal antibodies (ARA) in an immunohistochemical assay, which identifies serum antibodies against murine retina.

Methods:: Patients were referred to the Uveitis and Immunology service at the National Eye Institute for an evaluation of visual acuity or visual field loss thought to be of retinal origin. Visual acuity, ophthalmic exam, fundus photography and angiography, visual fields, and electrophysiologic testing were performed. 10 patients with clinical features of an autoimmune retinopathy were tested for ARA. Indirect immunoperoxidase staining of cryosections from normal mouse eyes was performed with serial two-fold dilutions of patient sera (from 1:40 to 1:1280). Serum reactivity at a dilution of greater than 1:160 was considered ARA positive.

Results:: Of the 10 patients with unexplained visual loss thought to be of retinal origin, 3 (30%) of 10 patients were found to have positive serum reactivity with immunostaining involving predominantly the nuclear layers (outer nuclear, inner nuclear, and ganglion cell layers). All three patients were on immunosuppressive therapy at the time of ARA testing. In one patient, anti-recoverin antibody testing was negative, but serum immunoreactivity was present with a 1:160 titer. Reduction in cone amplitudes and delay in implicit times were observed in all three patients. Rod responses were also diminished. Visual field testing revealed central and paracentral scotomas in 2 of 3 ARA positive patients.

Conclusions:: Autoimmune retinopathy may be characterized by loss of visual acuity and/or visual field. Abnormalities of cone and rod responses may be observed on electrophysiologic testing. Antibodies to mouse retinal antigens were observed in 30% of individuals suspected of having an autoimmune retinopathy despite immunosuppressive therapy. This ARA immunoassay may be a useful adjunct in the diagnosis of autoimmune retinopathy. Further studies are required to determine its specificity and sensitivity relative to currently available tests.

Keywords: retina • immunohistochemistry • uveitis-clinical/animal model