Letter to Editor
Virology Research Center, National Research Institute of Tuberculosis and Lung diseases (NRITLD), Shahid Beheshti University of Medical Sciences, Tehran, Iran,
Clinical Tuberculosis and Epidemiology Research Center, NRITLD, Shahid Beheshti University of Medical Sciences, Tehran, Iran
Coronavirus Disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged in December 2019 in China and quickly spread throughout the world. By June 24, 2020, the World Health Organization (WHO) reported the total number of 8,993,659 laboratory-confirmed cases leading to 469,587 deaths worldwide (1). COVID-19 has a range of clinical manifestations from asymptomatic cases to severe and life-threatening illnesses (2). The most severe form of the disease is the rapidly progressing failure of the respiratory system, presenting by severe dyspnea and profound hypoxemia, and may lead to acute respiratory distress syndrome (ARDS)(3) .
The pathophysiology of COVID-19 is under investigation and has not yet certainly defined. Like other severe forms of coronavirus diseases, the hyperactivation of the immune system resulting in hyper inflammation and cytokine storm syndrome has been postulated (4) . Most of the patients with the severe form of COVID-19 have higher serum levels of various inflammatory cytokines and chemokines, including interleukin-1β (IL-1β), IL-6, granulocyte colony-stimulating factor (G-CSF), granulocyte/macrophage colony-stimulating factor (GM-CSF), interferon-γ (IFN-γ), tumor necrosis factor (TNF), and macrophage inflammatory protein-1α (MIP1α)(5, 6) .