Non-Paraneoplastic Autoimmune Retinopathy: The First Case Report in Korea

Abstract

Autoimmune retinopathy (AIR) is an immune-mediated retinopathy, resulting from an immunologic process caused by the aberrant recognition of retinal antigens as autoantigens. The diagnosis of AIR involves the detection of antiretinal antibodies with concurrent clinical and electrophysiological evidence of retinopathy. A 40-year-old patient presented with progressive loss of bilateral vision over several months. A fundus examination was unremarkable. Spectral domain optical coherence tomography revealed a blurred photoreceptor ellipsoid zone at the subfoveal region in both eyes with more prominent disruption in the left eye. Full-field electroretinography (ERG) showed relatively normal rod and cone responses in the right eye, and decreased photopic bwaves with minimal attenuation of a-waves in the left eye. Multifocal ERG demonstrated slightly reduced amplitude of the inner segment ring in the right eye and decreased amplitudes and delayed latencies of all modalities in the left eye. The patient was suspected to have AIR and it was supported by positive Western blots for 23-kDa protein, enolase (46-kDa), aldolase (40-kDa), 62-kDa and 78-kDa proteins and by immunohistochemical staining of human retinal bipolar and ganglion cells. Despite the immunosuppressive treatment, the destruction of the retinal photoreceptors progressed, and immunosuppressive interventions produced very little visual improvement. We report on what is, to the best of our knowledge, the very first case of serologically confirmed nonparaneoplastic AIR in Korea.

Keywords: AIR; Autoimmune retinopathy; antiretinal antibodies; enolase; nonparaneoplastic autoimmune retinopathy; recoverin.

Fig. 1. Fundus photographs, SD-OCT and visual field examination. (A) Color fundus photography of both eyes showing no apparent abnormalities. (B) Initial SD-OCT revealing blurring of ellipsoid zone at subfoveal region, more severe in the left than in the right eye. (C) Two months later, follow up SD-OCT demonstrating more progressed disruption of the ellipsoid zone across the entire fovea in both eyes. (D) Initial 30-2 HVF revealing central scotoma only in the left eye. (E) Follow up 30-2 HVF after 4 months displaying more profound cecocentral field deterioration in both eyes. SD-OCT, spectral domain-optical coherence tomography; HVF, humphrey visual field.

Fig. 2. Results of initial examinations: full-field electroretinography (A), and multifocal electroretinography (B) or (A) Initial full field ERG of the right eye displaying relatively intact responses, with slightly attenuated photopic a- and b-waves in the left eye. (B) Initial mfERG of the right eye revealing slightly reduced amplitude of inner segment ring and diminished amplitudes and delayed latencies of all modalities in the left eye. ERG, electroretinography; mfERG, multifocal ERG.

Fig. 3. Western blot and immunohistochemical staining results of patient's serum. (A) The patient's serum was positive for 23-kDa protein, enolase (46-kDa), aldolase (40-kDa), 62-kDa and 78-kDa proteins in Western blotting. The arrows indicate positive controls (C1: a positive control for recoverin; C2: a positive control for enolase). (B) Moderate immunohistochemical staining of some human retinal bipolar and ganglion cells as well as photoreceptor cells was noted. Scale bar=50 µm.