IgG antibody patterns in aqueous humor of patients with primary open angle glaucoma and pseudoexfoliation glaucoma

There has been growing body of evidence indicating an immunological component in the pathogenesis of glaucoma. Several studies found specific antibodies in sera of glaucoma patients. Recently, we detected antibody profiles in aqueous humor of patients with normal tension glaucoma that showed significant differences when compared to control subjects. The aim of this study was to compare the IgG antibody patterns against retinal antigens in aqueous humor of patients with primary open angle glaucoma, pseudoexfoliation glaucoma, and control subjects then to identify some of the important biomarkers of this study.

Aqueous humor of 44 patients was analyzed: 15 patients with primary open angle glaucoma (POAG), 14 patients with pseudoexfoliation glaucoma (PEX), and 15 control subjects (CO). The aqueous was tested against western blots of bovine retinal antigens. The IgG antibody patterns were analyzed by multivariate statistical techniques. Some of the important biomarkers were identified via mass spectrometry (Maldi-TOFTOF).

All patients showed complex patterns of IgG antibodies against retinal antigens. The discriminant analysis revealed a statistically significant difference between the antibody profiles of the POAG and the CO group (p=0.00018). There was also a statistically significant difference between the antibody profiles of the PEX and the CO group (p=0.0013). Not only were up-regulations in the glaucoma groups observed, compared to controls, but also down-regulations. There was no significant difference between the antibody patterns of the POAG and PEX group. The identified biomarkers included heat shock protein 27, alpha-enolase, actin, and GAPDH.

We could show significant differences between the IgG antibody profiles of the glaucoma groups (PEX and POAG) and controls. The analysis of intraocular antibodies could provide further hints for autoimmune involvement in glaucoma.