Expression of TRAIL/TRAIL receptors in T-cell subtypes in the clinical presentations of myasthenia gravis

Introduction and Objective: Myasthenia gravis (MG) is an autoimmune disease caused through antibodies, which displays fluctuations and which is characterized by weakness of bulbar, extremity, ocular and respiratory muscles in varying extents with specific property manifested by increasing weakness as getting tired. Among these antibodies, anti-AChR is the most frequently seen and most known antibody in MG. These antibodies are made by B-lymphocytes; however adjuvant T-lymphocytes put contribution to generation of autoimmune response. Thymus has been attracting great attention on account of the fact that approximately 10-15% of the patients with MG have thymoma and 70% of them have thymus hyperplasia, and that significant part of these patients take advantage of thymectomy. Being also known as programmed cell death, apoptosis regulates the activities of central and peripheral T-cell during immune response. In this respect, this study aims to determine T-cell related TRAIL (TNF-related apoptosis-inducing ligand) receptor and ligand compositions, and to identify the role of TRAIL in progression of the disease in the patients with MG. In this way, it is also aimed to determine how TRAIL and its receptors affect the functioning of T-cells in pathophysiological mechanism of MG. Material and Method: This study covered 25 patients (13 female and 10 male patients) who applied to Neurology department and for whom the definitive diagnosis of MG was established in the light of electrophysiological and laboratory data as well as 16 healthy volunteers who bear resemblance to the former group in terms of age and gender distribution. On the basis of peripheral blood samples taken from the patients, expression profiles of TRAIL and its receptors in CD3+ CD4+ ve CD3+ CD8+ T-lymphocytes by way of flow cytometry; and associations of such determinations with clinical findings and treatment protocols of the patients were evaluated by using Spearman Rho Analysis. Findings: It was determined that in MG patient group TRAIL and its receptors were expressed at a higher level in both CD4+ and CD8+ T cells as compared to control group. Death Receptor-4 (DR4) and decoy receptors DcR1 and DcR2 were identified to have been positively correlated with the patients in CD8+ T cells, whereas such a correlation was not observed in CD4+ T cells. Conclusion: This study, which is aimed at evaluating the expression profile of TRAIL/TRAIL receptors in T-cell subtypes in the clinical presentations of MG, indicates that TNF and TRAIL/TRAIL receptor system also plays an active role in MG; and we are of the opinion that the findings obtained by this study would contribute to development of new gene therapy methods in MG mice models. Keywords: MG, thymus, TRAIL, apoptosis, CD4+, CD8+