47-kDa (Presumed α-Enolase)–Positive Autoimmune-Related Retinopathy and Optic Neuropathy (ARRON)

Abstract

The aim of the article is to report the presentation, diagnosis, and treatment of two cases of unexplained painless vision loss attributed to 47-kDa (presumed α-enolase)-positive autoimmune-related retinopathy and optic neuropathy (ARRON); to describe 47-kDa (presumed α-enolase)-positive ARRON as a subtype of ARRON; and to propose that serum anti-enolase antibody might be a serologic marker of the disorder. We have reviewed retrospectively of two patients with ARRON positive for an antibody to a 47-kDa retinal antigen presumed to be α-enolase. The two patients had progressive bilateral visual acuity and/or visual field loss, electroretinographic evidence for retinal dysfunction, and evidence for serum anti-retinal antibodies to a 47-kDa antigen (presumed α-enolase). Although clinically the patients had symptoms of retinal-based visual loss, neither patient had optic disc oedema, optic atrophy, or any ophthalmoscopically visible retinal abnormalities. Both patients were treated with immunosuppressive therapy. One patient achieved improvement in visual acuity with oral corticosteroids alone, but the other patient did not respond to steroid treatment and only achieved improvement in vision following plasmapheresis. After immunosuppressive treatment, follow-up serum antibody levels to a 47-kDa antigen (presumed α-enolase) levels were retested and were undetectable in both patients. We hypothesize that these two patients have a constellation of clinical and electrophysiologic findings suggestive of a 47-kDa (presumed α-enolase)-positive ARRON that we believe is subtype of ARRON and that serum α-enolase antibody might be a marker of the disorder.