Effect of Cytokines Gene Expression and Serum Level of Vitamin D on the Severity of COVID-19

 The COVID-19 disease is an emerging infectious disease that appeared in December 2019 in Wuhan, China. An uncontrolled systemic inflammatory response is one of the primary mechanisms causing death in this disease. In this study, the expression levels of some inflammatory cytokines, vitamin D, and some hematological and biochemical parameters were compared in patients with severe COVID-19 and mild types.

 In this cross-sectional study, 60 blood samples were taken from 30 severe coronavirus patients and 30 mild coronavirus patients. The expression levels of cytokines such as IL (interleukin)-6, interferon (IFN)-α, IL-12, transforming growth factor (TGF) β, IL-8 and tumor necrosis factor (TNF)-α were evaluated using Real-time PCR. A T-test was used for Statistical Analysis.

IL-6, IFN-α, IL-12, TGF-β, IL-8, and TNF-α cytokines in the peripheral blood of severe patients, were positive in 28/30 (93.33%), 27/30 (90%), 24/30 (80%), 25/30 (83.33%), 26/30 (86.66%), and 27/30 (90%) respectively. The positive rate of these cytokines in the mild patients were 20/30 (66.67%), 21/30 (70%), 18/30 (60%), 17/30 (56.67%), 19/30 (63.33%), 18/30 (60%), respectively. There was a statistically significant difference between these two groups in terms of cytokines biomarkers. A significant difference was found between both groups in terms of the serum level of lactate dehydrogenase (LDH), the mean number of lymphocytes and neutrophils as well as the mean percentage of neutrophils/ lymphocytes ratio (NLR).

 The expression of cytokine genes and their release into the peripheral blood was increased in both severe and mild patients with COVID-19. However, they were more intense in patients with severe symptoms than those with mild symptoms and can cause inflammatory and even destructive reactions. Vitamin D deficiency plays no role in causing severe COVID-19 in patients without risk factors. Severe COVID-19 is characterized by elevated serum levels of LDH and NLR≥3.45.