title: A case of paraneoplastic optic neuropathy and outer retinitis positive for autoantibodies against collapsin response mediator protein-5, recoverin, and α-enolase.
abstract: BACKGROUND
  Specific cross-reacting autoimmunity against recoverin or collapsin response mediator protein (CRMP)-5 is known to cause cancer-associated retinopathy or paraneoplastic optic neuropathy, respectively. We report a rare case with small cell lung carcinoma developing bilateral neuroretinitis and unilateral focal outer retinitis positive for these antibodies.
  
  
  METHODS
  A 67-year-old man developed bilateral neuroretinitis and foveal exudation in the right eye. Optical coherence tomography showed a dome-shaped hyperreflective lesion extending from inner nuclear layer to the photoreceptor layer at the fovea in the right eye. Single-flash electroretinography showed normal a-waves in both eyes and slightly reduced b-wave in the left eye. Results of serological screening tests for infection were within normal limits. The patient's optic disc swelling and macular exudation rapidly improved after oral administration of prednisolone. Systemic screening detected lung small cell carcinoma and systemic chemotherapy was initiated. Immunoblot analyses using the patient's serum detected autoantibodies against recoverin, CRMP-5, and α-enolase, but not carbonic anhydrase II. Neuroretinitis once resolved after almost remission of carcinoma on imaging but it recurred following the recurrence of carcinoma.
  
  
  CONCLUSIONS
  The development of neuroretinitis in this cancer patient with anti-retinal and anti-optic nerve antibodies depended largely on the cancer activity, suggesting the possible involvement of paraneoplastic mechanisms. Patients with paraneoplastic optic neuropathy and retinopathy are likely to develop autoimmune responses against several antigens, thus leading to various ophthalmic involvements.
authors.forename: Michiyuki
authors.initials: M
authors.lastname: Saito
authors.affiliation: Department of Ophthalmology, Hokkaido University Graduate School of Medicine, Sapporo, Japan. wsaito@med.hokudai.ac.jp.
authors.forename: Wataru
authors.initials: W
authors.lastname: Saito
authors.forename: Atsuhiro
authors.initials: A
authors.lastname: Kanda
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ohguro
authors.forename: Susumu
authors.initials: S
authors.lastname: Ishida
mesh_terms: D000368:Aged; D001323:Autoantibodies / Q000276:immunology*; D006801:Humans; D006867:Hydrolases; D008175:Lung Neoplasms / Q000150:complications; D008297:Male; D008869:Microtubule-Associated Proteins; D009419:Nerve Tissue Proteins / Q000276:immunology*; D009901:Optic Nerve Diseases / Q000276:immunology*; D059545:Paraneoplastic Syndromes, Ocular / Q000276:immunology*; D010751:Phosphopyruvate Hydratase / Q000276:immunology*; D051603:Recoverin / Q000276:immunology*; D012173:Retinitis / Q000276:immunology*; D055752:Small Cell Lung Carcinoma / Q000150:complications
chemical_list: D001323:Autoantibodies; D008869:Microtubule-Associated Proteins; D009419:Nerve Tissue Proteins; D051603:Recoverin; C415087:DPYSL5 protein, human; D006867:Hydrolases; D010751:Phosphopyruvate Hydratase