Abstract
Purpose: :
To examine if specific serum anti-retinal autoantibodies can predict the phenotype and progression of paraneoplastic and autoimmune retinopathy.
Methods: :
Patients with sudden unexplained loss of vision were referred for evaluation. Retinal function was evaluated by ophthalmologic examination, including electroretinography. Antibodies against human retinal proteins were tested by Western blotting and ELISA. A proteomic map of human retinal proteins was prepared.
Results: :
Immunoblotting analysis of patient sera revealed autoantibodies that specifically recognized photoreceptor proteins (transducin-α, arrestin, recoverin), glycolytic enzymes (enolase, aldolase), and other functionally important retinal proteins (carbonic anhydrase II). These antibodies were more frequent than any other retinal proteins and antibody titers were higher than in normal subjects. The identity of these proteins was confirmed by mass spectrometric analysis. When the seropositive patients were grouped according to their autoantibody profiles, their clinical findings revealed similarities in visual field and ERG patterns and new phenotypes different from anti-enolase and anti- recoverin retinopathies were identified. Patients with anti-transducin-α autoantibodies were represented by a majority of women, were usually without cancer, and were younger (54.6 years) than typical CAR patients (63 years), and featured defects in rod (scotopic) photoreceptor function. In contrast, there was a poor correlation of specific retinal presentation with the presence of anti-carbonic anhydrase II autoantibodies. Anti-CAII antibodies are found more frequently in male patients irrespective of cancer, and are more likely a general indication of an autoimmune process than a specific subtype of AR.
Conclusions: :
Antibodies against specific retinal autoantigens are associated with certain retinal phenotypes and help predict the prognosis for different subtypes of AR. Anti-recoverin CAR is almost invariably associated with cancer and is associated with equal loss of rod and cones retinal responses, while anti-enolase retinopathy typically presents with cone dysfunction and is equally represented in cancer and non-cancer patients. Anti-transducin-α retinopathy features defects in rod (scotopic) photoreceptor function and is typically not associated with cancer. Proteomic analysis of bands also more confidently identified immunoreactive retinal proteins and provided important evidence for the mechanisms of retinal damage.
Keywords: autoimmune disease • CAR • retinal degenerations: hereditary