Abstract
Advanced glycation end products (AGEs), and particularly the unique AGE10 epitope, may be a potential biomarker
of immunopathology in rheumatic diseases. They may be associated with inflammation, joint damage and ossification processes. AGE10 present in human and animal tissues could be detected with monoclonal antibody against melibiosederived glycation product MAGE synthesized in anhydrous conditions. This MAGE product was different from the classic synthesis in water solution. The epitope was determined in serum with ELISA using these anti-MAGE monoclonal antibodies. This work aims to determine serum AGE10 levels in patients with reactive arthritis (ReA)-caused with Chlamydia trachomatis (group 2) and ReA with C. trachomatis during the reactivation of EBV infection (group 3). Additionally, ankylosing spondylitis (AS) patients (group 4) were involved in the study, due to the potential evolution of ReA toward AS. The control group maintained physiological AGE10 levels (316 μg/ml), while the combined infection group showed elevated AGE10 (850 μg/ml) compared to the chlamydial-only group (17 μg/ml). Fluorescent fAGE were at the highest level in AS patients. A striking finding was the complete absence of detectable AGE10 antigen in the AS group, coinciding with notably elevated immune complex AGE10–anti-AGE10 levels. A similar pattern was observed in patients with ReA caused by C. trachomatis alone (Group 2), albeit to a lesser extent. In contrast, both the control group and patients with ReA associated with EBV coinfection (group 3) displayed an inverse relationship, characterized by higher antigen levels and lower immune complex concentrations. Thus, diminished level of AGE10 could be caused, besides local accumulation,
also by immune complexes formation, a pathogenic factor. Therefore, evaluating disease activity in ReA and AS is
crucial to further our understanding of the pathophysiology of AGEs formation and predicting prognosis.
Keywords Advanced glycation end products (AGEs) · AGE10 · Reactive arthritis · Ankylosing spondylitis · Chlamydia
trachomatis · Epstein–Barr virus · Immune complexes · Oxidative stress

Advanced glycation end products (AGEs) are formed in a nonenzymatic reaction of the reducing sugars with amino groups of proteins, lipids, and nucleic acids of different tissues and body fluids. A relatively small number of studies have been conducted on the role of AGEs in allergic inflammation. In this study, patients with allergic rhinitis (AR) were examined for the presence of Epstein-Barr virus and the content of fluorescent and nonfluorescent AGEs. We have also determined the level of a unique epitope (AGE10) which was recently identified in human serum using monoclonal antibodies against synthetic melibiose-derived AGE (MAGE). The levels of AGE10 determined with an immunoenzymatic method revealed no significant difference in the patients' blood with intermittent AR and chronic EBV persistence in the active and latent phases. It has been shown that there is a statistically significantly smaller amount of AGEs and pentosidine in groups of patients, both with and without viremia, than in healthy subjects. In turn, higher levels of immune complexes than of AGE10 were detected in the groups of patients, in contrast to the control group, which had lower levels of complexes than AGE10 concentration. In patients with active infection, there is even more complexes than of noncomplexed AGE10 antigen. The lower level of AGE in allergic rhinitis patient sera may also be due, besides complexes, to allergic inflammation continuously activating the cells, which effectively remove glycation products from the body.