Abstract
Purpose: :
In the past decade multiple studies demonstrated changes in serum autoantibody profiles of glaucoma patients, leading to a differentiation between healthy individuals and glaucoma subjects with a high sensitivity and specificity. The aim of this study was to analyze autoantibody patterns in tear fluid or glaucoma patients and healthy subjects, which would allow the analysis in a non-invasive manner and furthermore using a body fluid, which is closer to the site of damage.
Methods: :
Tear samples from 31 controls (CO) and 31 primary open-angle glaucoma patients (POAG) were collected using Schirmer strips, followed by the elution of tear proteins using 200 µl PBS per strip. For the analysis of autoantibody reactivities we used customized protein microarrays equipped with 56 different human antigens. Arrays were incubated with tear solutions, followed by treatment with a fluorescence labeled anti-IgG antibody for visualization of the antibody-antigen-reactions. The emitted signals were digitized and the spot intensities compared using multivariate statistical techniques e.g. analysis of discriminance.
Results: :
Tear samples showed complex autoantibody reactivities in CO subjects and POAG patients against 80% of the tested antigens. The statistical analysis revealed 17 autoantibody reactivities to be significantly altered in the glaucoma group (P<0.05), in which some of the marker reactivities were increased and some decreased in comparison to the CO group. Amongst others, significantly shifted reactivities were detected for HSP10, HSP27, MBP and Protein S100 (each P≥0.005). We reached a sensitivity and specificity ≥80% (AUC of ROC-curve r>0.87) using artificial neural networks for pattern recognition and classification of prospective glaucoma tear samples.
Conclusions: :
In the present study we demonstrated that the majority of the autoantibodies found significantly altered were identical with antibody markers found in serum samples in previous studies. The classification performance of tear autoantibody patterns proved efficiency for the detection of glaucoma patients. Considering the fact that tear sampling is a fast and easy standard procedure in ophthalmologic examinations, tear autoantibody patterns may become a powerful tool in glaucoma diagnosis.
Keywords: clinical research methodology • proteomics