Clinical Association of TSH Receptor Antibody and Related Autoimmune Markers with Subclinical Graves’ Disease: A Study from Eastern Indian Population

Abstract

Introduction: Graves’ Disease (GD), the leading cause of hyperthyroidism is caused by interaction between various autoantibodies generated as a result of autoimmune dysregulation in genetically suspected individuals. Aim: To study the prevalence of serum levels of Thyroid Stimulating Hormone (TSH) Receptor Antibody (TRAb), Anti Thyroid Peroxidase Antibody (Anti TPOAb) and Anti Thyroglobulin Antibodies (Anti TgAb) in subclinical cases of GD. Materials and Methods: This was a hospital based crosssectional study conducted in the Department of Biochemistry, in a tertiary care hospital, over a period of one and half years from January 2019 to June 2020. A total of 120 patients with subtle symptoms of GD of age 30 to 60 years and same number of age and sex matched healthy controls were enrolled for the study. Collection of data was done and serum TRAb was estimated by Enzyme Linked Immunosorbent Assay (ELISA), while AntiTPO and AntiTg antibodies were measured using Electrochemiluminescence Immunoassay (ECLIA). Results: Serum levels of all the three antibody titres were found to be significantly higher in cases compared to controls. When diagnosis and differentiation of GD was done between cases and controls based on TRAb positivity (80.0%) or negativity (18.0%), it was found to have a sensitivity of 80.0% and specificity 98.3%. TRAb also had positive and negative predictive values of 97.9% and 84.3%, respectively. TRAb positive cases also had higher levels of Anti TPO and Anti TgAb in comparison to TRAb intermediate or negative group. Conclusion: Prevalence of high titres of autoantibodies especially TRAb are pathognomonic of early GD. Their detection in covert stages of disease shall provide insight into predicting outcome and frame management strategies in patients with this thyroid disorder.