Abstract
Purpose: :
In previous studies changes in the antibody profiles against ocular antigens have been shown in glaucoma patients. All studies could demonstrate consistent and specific up- and downregulations of immunoreactivities in glaucoma compared to controls and suggest a role for autoimmune involvement and changes in the natural autoimmunity in glaucoma. In order to search for new general autoimmune biomarkers for glaucoma, we performed a protein microarray analysis using non-ocular antigens.
Methods: :
The reactivity of antibodies from six sera, tears, and aqueous humors of patients with primary open angle glaucoma and healthy controls was tested against proteins on ProtoArray Human Protein Microarray (Invitrogen, Carlsbad, USA) containing 8000 proteins immobilized on glass slides. After visualizing and digitizing, the spot intensities were analyzed by multivariate statistical techniques.
Results: :
All samples demonstrated good signal to background ratio on the arrays, with slightly higher background seen for the serum samples. More than 271 spots were significantly up- or downregulated in POAG sera. It is remarkable that considering the 20 most significant biomarkers in all three fluids, approx. 50 % of them were downregulated such as HSP70/90 organizing protein. Furthermore, a huge number of up-regulations were found including a number of proteins known to be associated with neuronal structures and/or glaucoma. However, not all of them were overlapping between the three sets of biomarkers. E.g., NRTK3 was identified as a candidate biomarker from the tear samples, while the related neurotrophin receptors NRTK1 and NRTK2 were identified as candidate interactors from sera.
Conclusions: :
In this study using 8000 autoimmune related, non-ocular antigens, we were able to demonstrate significant up- and down-regulations of autoimmune reactivities in sera, tears, and aqueous humor of glaucoma patients. Thus, this study provides further hints for complex changes in the natural autoimmunity in glaucoma patients and after confirmation in subsequent studies, the potential biomarkers could lead to new therapeutic drug targets for innovative immunomodulatory treatments.
Keywords: immunomodulation/immunoregulation • autoimmune disease