Tehran University of Medical Sciences Acta Medica Iranica 0044-6025 61 5 2023 08 23 257 263 Vahid Asgharzadeh Student Research Committee, Tabriz University of Medical Sciences, Tabriz, Iran Mir Reza Valiollahzadeh Medical Philosophies and History Research Center, Tabriz University of Medical Sciences, Tabriz, Iran Zahra Taghinejad Hematology and Oncology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran Mohammad Asgharzadeh Biotechnology Research Center, Faculty of Paramedicine, Tabriz University of Medical Sciences, Tabriz, Iran Jalil Rashedi Tuberculosis and Lung Disease Research Center, Tabriz University of Medical Sciences, Tabriz, Iran Behroz Mahdavi poor Department of Laboratory Sciences, Faculty of Paramedicine, Tabriz University of Medical Sciences, Tabriz, Iran Hossein Jalaei Nobari Department of Islamic Education, Faculty of Paramedicine, Tabriz University of Medical Sciences, Tabriz, Iran Ahmad Ali Khalili Cardiovascular Research Center, Tabriz University of Medical Sciences, Tabriz, Iran. Yousof Khairy Department of Islamic Education, Faculty of Paramedicine, Tabriz University of Medical Sciences, Tabriz, Iran Amir Ali Mir Mazhari Department of Laboratory Sciences, Faculty of Paramedicine, Tabriz University of Medical Sciences, Tabriz, Iran 2021 08 25 2023 01 27 Following the discovery of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in China, it has been transmitted to travelers through respiratory droplets and distributed worldwide. Viral, environmental, and host factors all play a role in getting infected with the virus and having severe forms of the disease named coronavirus disease 2019 (COVID-19). Diabetes is one of the most important host risk factors in the progression and severity of COVID-19. In diabetes, hyperglycemia and protein glycosylation increase pro-inflammatory cytokines levels and suppress innate and adaptive immune system by impairing the function of neutrophils, macrophages, and lymphocytes, especially regulatory T lymphocytes. The compromised immune system in diabetic patients makes them vulnerable to infectious diseases like COVID-19. Correspondingly, people with diabetes are usually treated with angiotensin-converting enzyme (ACE) inhibitors and angiotensin II Type-I receptor blockers (ARBs), which increase ACE2 expression as a receptor for SARS-CoV-2. Thus, diabetic patients are more likely to develop severe forms of COVID-19 and die due to chronic inflammation and impaired immune function. https://acta.tums.ac.ir/index.php/acta/article/view/9627 https://acta.tums.ac.ir/index.php/acta/article/download/9627/5780