COVID-19 and Autoimmunity: Unravelling the GAD65 Connection in Non-diabetic Patients

Introduction: The Coronavirus Disease-2019 (COVID-19) pandemic has raised significant concerns regarding its longterm health impacts, particularly among individuals without preexisting conditions. Emerging evidence suggests a potential link between Severe Acute Respiratory Syndrome-Corona Virus-2 (SARS-CoV-2) infection and autoimmune responses, including the development of Type 1 diabetes. GAD65 (Glutamic Acid Decarboxylase 65) antibodies have been identified as key markers in the autoimmune pathway leading to Type 1 diabetes. Aim: To investigate the development of GAD65 antibodies at discharge in a cohort of non-diabetic COVID-19 patients as well as the relationships between glycaemic control, inflammatory markers, and severity of illness in a cohort of non-diabetic COVID-19 patients. Materials and Methods: The present cross-sectional observational study included 69 non-diabetic patients diagnosed with COVID-19 who were admitted to Dr. D. Y. Patil medical college, hospital and research centre, Pune, Maharashtra, India between October 2020 to October 2022. Data regarding demographic and biochemical parameters, including HbA1c and various inflammatory markers {Lactate Dehydrogenase (LDH), ferritin, D-Dimer, C-Reactive Protein (CRP), Erythrocyte Sedimentation Rate (ESR)} and development of GAD65 antibodies were collected at discharge. Statistical analyses included Pearson’s correlation coefficients and Kruskal-Wallis tests to evaluate associations. Results: The study involved 69 participants with a median age of 48 years, ranging from 36 to 64 years including 47 males (67.1%) and females 22 (31.4%). The findings revealed no significant correlations between HbA1c and inflammatory markers {LDH (r-0.05, p-0.681); ferritin (r-0.069, p-0.576); CRP (r-0.027, p-0.824); ESR (r-0.009, p-0.942)}. However, D-Dimer levels were significantly higher in patients with severe illness (p= 0.022). One patient developed GAD65 antibodies at discharge, suggesting potential autoimmune development after COVID-19 infection. Conclusion: The study underscores the non-significant association of traditional inflammatory markers with glycaemic control while highlighting D-Dimer’s relevance in illness severity. The development of GAD65 antibodies in a patient raises considerations for emergence of autoimmunity which may lead to type 1 diabetes. Further research is warranted to explore these associations in broader populations.