Analysis of IgG antibody patterns against retinal antigens and antibodies to α-crystallin, GFAP, and α-enolase in sera of patients with “wet” age-related macular degeneration

Abstract

Background The aim of this study was to compare the IgG antibody patterns against retinal antigens in sera of patients with age-related macular degeneration (AMD) and healthy subjects to learn more about possible immunological aspects of this disease and to identify some of the most important antigens.Methods Sera of 140 patients were analyzed: healthy volunteers (CO, n=101) and patients with "wet" age-related macular degeneration (AMD, n=39). The sera were tested against western blots of bovine retinal antigens. The IgG antibody patterns were analyzed by multivariate statistical techniques and some antigens were identified via LC-MS/MS.Results All patients showed complex patterns of IgG antibodies against retinal antigens. The discriminant analysis revealed a statistical significant difference between the antibody profiles of the AMD and the CO group (P=0.000023). Not only up-regulations of antigen-antibody-reactivities in the AMD group at some molecular weight ranges, e.g. at 46 and 52 kDa, could be seen, but also down-regulations, e.g. at 18 and 36 kDa. The 18 kDa antigen band was identified as alphaB-crystallin, the band at 46 kDa as alpha-enolase, and one at 52 kDa as glial fibrillary acidic protein.Conclusions We could demonstrate that both groups (wet AMD and CO) show complex IgG antibody patterns against retinal antigens, which are highly specific for each group. This provides further hints for the immunological basis of the disease. These changes in the antibody profiles in "wet" AMD could represent a secondary response to retinal damage or can play a causative role in the disease.