Abstract
Purpose: :
In previous studies significant alterations in IgG autoantibody patterns of glaucoma patients have been shown. We could demonstrate up- as well as down-regulated immunoreactivities to ocular and non-ocular antigens. The aim of this investigation was to identify new autoimmune biomarkers for open angle and normal tension glaucoma as well as ocular hypertension by means of an advanced high-density protein array approach.
Methods: :
For the analysis of autoantibody reactivities, sera of patients with primary open angle glaucoma (POAG, n=20) and normal tension glaucoma (NTG, n=20) are compared with healthy subjects (CTRL, n=20) and patients with ocular hypertension (OHT, n=20). Two pools of ten sera each were created for each group, which were incubated on nitrocellulose-coated slides with 3800 immobilized randomly selected human proteins from the UNIclone® library (UNIchip®, Protagen, Dortmund, Germany). For visualization of the resultant antigen-antibody complexes, slides were treated with a secondary fluorescence labeled antibody (Dylight 650) followed by confocal laser scanning. After data normalization spot intensities were compared and group differences were analyzed.
Results: :
Overall we could detect complex autoantibody patterns in all groups. Proteins at least 1.6 fold decreased or 1.8 fold increased were considered significantly altered. Out of 15 shifted immunoreactivities in POAG, 7 in NTG and 7 in OHT in comparison to CTRL-group only one (TTLL12, tubulin tyrosine ligase-like family member 12) was found in both glaucoma groups (>1.85 fold increase). All others were unique to their respective groups (e.g. DUSP2 for POAG (dual specificity phosphatase 2, 2.3 fold increase), PRG2 (plasticity related gene 2, 2.14 fold increase) for NTG, SRP14 (signal recognition particle 14kDa, 2.02 fold increase) for OHT) and might be potential biomarkers.
Conclusions: :
In this study a panel of 3800 randomly chosen antigens we were able to detect a small number of significant up- and down-regulations of autoimmune reactivities in sera of patients. After further validation in subsequent studies, these potential biomarkers could lead to new therapeutic drug targets for innovative immunomodulatory treatments and give further insights in the pathogenesis of eye diseases.
Keywords: immunomodulation/immunoregulation • proteomics