Abstract
Purpose:
Using protein microarrays we could previously show evidence for differentiation between pseudoexfoliation syndrome (PEXS) and pseudoexfoliation glaucoma (PEXG) on the basis of sera autoantibody profiles. To gain further insight into immunoreactivities of PEXS and PEXG patients we analyzed the IgG-autoantibody reactivities in aqueous humor of these patients and cataract controls (CAT).
Methods:
Aqueous humor of patients with PEXG (n=45), PEXS (n=17) and controls with cataract (n=41) were used for antibody analysis. Analyses were performed using protein-microarrays, which were prepared by spotting 51 different ocular antigens onto microarray slides. Arrays were incubated with aqueous humor (1:10), and were treated with fluorescence labeled (Cy5) anti-human IgG antibodies and scanned with a high-resolution confocal scanner. Emitted signals were digitized and spot intensities were compared using diverse statistical techniques, such as ANOVA and multivariate discriminant analysis. A neuronal network was trained with 50% of the data and used to classify the other 50% of the patients as CAT, PEXS or PEXG.
Results:
Intensity of the autoantibody-IgG-reactions was increased in PEXG in comparison to PEXS and CAT, e.g. HSP 10 (P≤0.001), β-S-Crystallin (P≤0.0001) and Proteinase K (P≤0.001). The autoimmunity of PEXS is similar to CAT with some antigens that differ significantly between PEXS and PEXG as well as between PEXS and CAT, e.g. the immunreactivity of PEXS was increased against α-Synuclein (P≤0.01) and decreased against calreticulin (P≤0.001) in comparison to PEXG and CAT. Based on 10 antigens with the strongest autoimmunity, we were able to differentiate between PEXG and CAT (area under curve (AUC) =0.81) with a sensitivity and specificity of 80% and between PEXS and PEXG (AUC=0.96) with a sensitivity and specificity of 90%.
Conclusions:
Analysis of IgG autoantibody patterns in aqueous humor revealed significant shifts in autoimmunoreactivities of CAT, PEXS and PEXG patients. PEXG patients showed an increased immunoreactivity in comparison to CAT and PEXS. There is evidence for differentiation between PEXS and PEXG on the basis of specific autoantibody profiles
Keywords: 427 aqueous •
663 proteomics •
432 autoimmune disease