A. Achir

Expression of receptor for advanced glycation end-products (RAGE) in thymus from myasthenia patients

OBJECTIVES The receptor for advanced glycation end-products (RAGE) is a membranous immunoglobulin involved in the pathogenesis of numerous autoimmune diseases and tumors. The aim of this study was to investigate the possible involvement of RAGE in the pathogenesis of myasthenia gravis. MATERIAL AND METHODS This prospective study included 41 cases of myasthenia gravis treated at our institution between 2010 and 2015. There were 18 men and 23 women, with an average age of 36.44±14.47 years. The majority of patients (24.4%) were classified as IIb, according to MGFA scoring, and 21 of them required corticosteroid and/or immunosuppressive treatment. Assessment of RAGE in thymus specimens was done by immunohistochemistry using RAGE antibody (C-term). RAGE expression was assessed according to various clinical, paraclinical and pathological parameters. RESULTS Histopathological studies found 18 thymomas, 17 hyperplasias and six other types of pathology. Expression of RAGE was negative/weak in 19 cases and moderate/strong in 22 cases. It was more important in thymoma type B2 (P<0.001) and when the duration of myasthenia was short (P=0.04), and was not significantly related to either myasthenia clinical severity or preoperative treatment. CONCLUSION Our results suggest that the RAGE pathway is involved in myasthenia gravis pathophysiology, especially at disease onset, and in forms with thymomas. Further studies would be indispensable to explore other aspects of this signaling pathway, especially the potential role of different ligands and soluble forms of RAGE.