Abstract
Purpose: :
To evaluate therapeutic response to immunosuppressive therapy using systemic steroids, intraocular and systemic IVIg administration in dogs with spontaneously occurring auto-immune retinopathies (AIR).
Methods: :
Diagnosis of AIR was established in 47 dogs based on history (sudden onset of blindness with near normal retinal appearance), extinguished ERG tracings, absent photoreceptor-mediated spectral pupil light reflex (PLR) response and evaluation of serum samples for retinal auto-antibodies (using Western Blot and ELISA). Optical coherence tomography was performed in 20 dogs to evaluate retinal thickness. Generalized screening for presence of systemic neoplasia was performed in all patients (thoracic and abdominal radiographs, MRI/CT of brain).
Results: :
Neoplasia screening revealed presence of tumors in 9 AIR dogs (19%). Systemic steroid therapy (prednisolone 1mg/kg BW twice daily) resulted in functional recovery in 10 patients (21%). Systemic IVIg treatment resulted in functional recovery in 12 of 16 treated patients (75%). Intraocular IVIg administration resulted in functional recovery in 5 of 11 treated patients (45%). AIR serum analysis showed presence of following retinal auto-antibody fractions: 20, 23, 33, 35, 46, 60, 64, 65, 67, 82 and 120 kDa. AIR dogs which responded to any form of treatment usually had only one (or two) fractions of antibodies, most frequently 20 and 23 kDa. Patients with >2 fractions of auto-antibodies and fractions which were >35kDa were usually non-responsive to any therapeutic treatments. Retinal thickness of 150 micrometers or less (normal thickness 180-200 microm) was associated with poor response to treatment with systemic and intraocular IVIg.
Conclusions: :
Canine AIR patients share numerous similarities with human AIR patients. Systemic and intraocular IVIg therapy is associated with significant recovery of visual function in canine AIR patients, which may be utilized for developing novel treatment protocols for human patients.
Keywords: autoimmune disease • retinitis • tumors