Identifcation of serum biomarkers in patients of exfoliative glaucoma in Scandanavian population. : Autoimmune profiling by microarray technology.

Sammanfattning: Glaucoma is the leading cause of irreversible blindness, estimated to affect more than 79 million people by the year 2020. It is a group of optic neuropathies that is found to be associated with autoimmunity. One of its types is exfoliative glaucoma which is more prevalent in certain areas of the world including Scandinavia. It is more aggressive and often resistant to conventional therapy. The best treatment options for glaucoma lies at the early detection of the disease. The aim of the study was to identify serum biomarkers in patients of exfoliative glaucoma in the Scandinavian population. Serum samples of 30 patients of exfoliative glaucoma and 10 control subjects were profiled on epoxy coated protein microarrays expressing immobilized His-tagged human antigens. 3072 antigens were selected after a literature review which included the ones expressed in eye and retina. Protein-microarrays were incubated with sera, and occurring immunoreactivities were visualized with fluorescence labelled secondary antibodies. To detect changes, spot intensities were digitized and analysed with different statistical methods. Binary logistic regression was used to classify diseased and controls. A significant increase of antibodies against IRAK4 antigen was detected among serum samples of the controls (p = 0.002) as compared to the exfoliative glaucoma patients. Antibodies against four other antigens were found to be more prevalent in serum samples of exfoliative glaucoma patients although not significantly. These included FUT2, VAV2, and GPATCH8 and PFKFB1. The logistic regression was able to classify diseased and controls with 100 percent accuracy depending on 11 selected reactive antigens. Out of the 3072 antigens, IRAK4 was found to be the only significant antigen with increased reactivity in controls as compared to exfoliative glaucoma patients. IRAK4 has a role in innate immunity and signal transduction, antibodies against it may have a neuroprotective effect in glaucoma. However, this is an initial exploratory study based on only 40 samples and further experiments with a larger sample size needs to be performed.