Abstract
Purpose:
To characterize the humoral response against retinal autoantigens after laser photocoagulation.
Methods:
Serum samples were collected from 10 diabetic patients before and four weeks after initial panretinal photocoagulation. Collected serum samples were cross-blotted with human retinal protein extracts on a 2-dimensional gel. Retinal antigens recognized by patients’ serum were identified using LC-MS/MS. Similarly, laser 5 adult Brown Norway rats that were sacrificed two weeks after laser photocoagulation. Extracted retinal proteins were cross-blotted with pre- and post-laser serum samples. Retinal antigens were identified using mass spectroscopy.
Results:
Serum from untreated patients with proliferative diabetic retinopathy was positive 8 common autoantibodies against retinal proteins, i.e. carbonic anhydrase, glyceraldehyde-3-phosphate dehydrogenase, voltage-dependent anion-selective channel protein 1, creatine kinase B-type, alpha enolase, vimentin, pyruvate kinase and fructose-bisphosphate aldolase A. Laser photocoagulation boosted up antibody production against these proteins, as well as induced de novo antibodies against heat shock cognate 71 kDa protein, cellular retinoic acid-binding protein 1, tubulin beta, vimentin, aldolase, GFAP, aconitate hydratase and gamma-enolase. Antibodies against six of the identified retinal autoantigens (heat shock cognate 71 kDa protein, alpha enolase, creatine kinase B-type, glyceraldehyde-3-phosphate dehydrogenase, tubulin beta and pyruvate kinase) were also observed after the photocoagulation in the rat.
Conclusions:
Humoral response to retinal autoantigens is common among untreated patients with proliferative diabetic retinopathy due to leaky blood-retinal barrier. Laser photocoagulation boosts up this humoral response and induces additional retinal autoantibodies. Some of these autoantibodies may reflect neuronal damage, i.e. glyceraldehyde-3-phosphate dehydrogenase, whereas other may explain retinal function loss in diabetes, (pyruvate kinase, carbonic anhydrase) and/or after panretinal photocoagulation (heat shock cognate 71 kDa protein, alpha enolase).
Keywords: 499 diabetic retinopathy •
663 proteomics •
555 immunomodulation/immunoregulation