Abstract
Purpose :
The currently available methods for detecting anti-retinal antibodies in autoimmune retinopathy often do not identify the exact protein against which the antibodies are directed. Phage immunoprecipitation sequencing is a new technique for autoantigen discovery that is based on a synthetic representation of a complete human peptidome. The purpose of this case series study is to use phage immunoprecipitation sequencing to identify autoantigens in the plasma of autoimmune retinopathy patients.
Methods :
After institutional review board approval, plasma was obtained from eleven patients with autoimmune retinopathy and eight controls without a history of eye or autoimmune disease. The samples were each mixed with a T7-phage peptide library and phage immunoprecipitation sequencing was used to extract and sequence putative autoantigens. An informatics pipeline was used to identify autoantigens that were enriched for in autoimmune retinopathy patients. These autoantigens were characterized for their expression in the retina. The molecular weights of these autoantigens were also compared to the molecular weights of proteins detected by anti-retinal antibody Western blot in these same patients.
Results :
Several autoantigens were enriched for in cases and not detected in controls. Autoantigens RTN3, PRPF6 and B3GNT8, three proteins expressed in the retina, were detected in plasma from one patient each and no controls. Only one patient had an autoantigen within a similar MW range as that detected by anti-retinal antibody Western blot. This was the patient whose plasma was enriched for the autoantigen B3GNT8 (43.4 kDa) and she had an anti-retinal antibody Western blot band for a 42 kDa protein. POLR3A autoantibodies, which have a well-characterized role in scleroderma, were detected in two cases and no controls.
Conclusions :
In this pilot study, phage immunoprecipitation sequencing detected autoantigens that are expressed in the retina as well as scleroderma-related autoantigens in autoimmune retinopathy patients. Additional studies are needed to determine if these autoantigens are truly pathogenic and if phage immunoprecipitation sequencing can be used more broadly to identify autoantigens in autoimmune retinopathy.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.