Mahmoodpoor, Ata, Hosseini, Maryam, Soltani-Zangbar, Sadegh, Sanaie, Sarvin, Aghebati-Maleki, Leili, Saghaleini, Seyed Hadi, Ostadi, Zohreh, Hajivalili, Mahsa, Bayatmakoo, Zhinous, Haji-Fatahaliha, Mostafa, Babaloo, Zohreh, Farid, Sima Shahmohammadi, Heris, Javad Ahmadian, Roshangar, Leila, Rikhtegar, Reza, Kafil, Hossein Samadi, and Yousefi, Mehdi
• COVID-19 is a novel viral infection that has been a worldwide health threat as currently infected more than eighty million people in the world. • Reduced number and function of T cells were observed in ICU-admitted COVID-19 patients may have a correlation with the severity of the disease. • Hypercholesterolemia and hyperlipidemia could be important prognostic factors to determine the severity of the SARS-CoV-2 infection. Coronavirus disease 2019 (COVID-19) is a novel viral infection threatening worldwide health as currently there exists no effective treatment strategy and vaccination programs are not publicly available yet. T lymphocytes play an important role in antiviral defenses. However, T cell frequency and functionality may be affected during the disease. Total blood samples were collected from patients with mild and severe COVID-19, and the total lymphocyte number, as well as CD4+ and CD8 + T cells were assessed using flowcytometry. Besides, the expression of exhausted T cell markers was evaluated. The levels of proinflammatory cytokines were also investigated in the serum of all patients using enzyme-linked immunesorbent assay (ELISA). Finally, the obtained results were analyzed along with laboratory serological reports. COVID-19 patients showed lymphopenia and reduced CD4+ and CD8 + T cells, as well as high percentage of PD-1 expression by T cells, especially in severe cases. Serum secretion of TNF-α, IL-1β, and IL-2 receptor (IL-2R) were remarkably increased in patients with severe symptoms, as compared with healthy controls. Moreover, high levels of triglyceride (TG) and low density lipoprotein cholesterol (LDL-C), were correlated with the severity of the disease. Reduced number and function of T cells were observed in COVID-19 patients, especially in severe patients. Meanwhile, the secretion of proinflammatory cytokines was increased as the disease developed. High level of serum IL-2R was also considered as a sign of lymphopenia. Additionally, hypercholesterolemia and hyperlipidemia could be important prognostic factors in determining the severity of the infection. [ABSTRACT FROM AUTHOR]