Higher expression of monocyte chemotactic protein 1 in mild COVID-19 patients may be correlated with the inhibition of IFN signaling

Abstract

Background: The level of chemokines was markedly elevated in severe COVID-19 patients. But the role of chemokines in mild COVID-19 has not yet been established. However, most of the COVID-19 patients in Shiyan City, China, had mild cases. The purpose of this study is to evaluate the level of chemokines in mild COVID-19 patients and explore the correlation between chemokines and host immune response.Methods: In this study, the level of chemokines in the serum for COVID-19 patients in Shiyan City was detected by ELISA. The expression of chemokine receptors and other signal molecules was measured by real-time PCR.Results: We first demonstrated that COVID-19 patients are characterized by higher level of chemokines. Meanwhile, monocyte chemotactic protein 1 (MCP-1) has also shown higher expression in patients with mild cases of COVID-19. The receptor of MCP-1, CCR2, was also found to be expressed at higher level in the same mild COVID-19 patients. Finally, we found the downregulation of interferon regulatory factor 3 (IRF3) was significantly negative correlated with the concentration of MCP-1 in mild COVID-19 patients.Conclusion: Higher expression of MCP-1 in mild COVID-19 patients may be correlated with the inhibition of IFN signaling. The finding adds our understanding to the immune-pathologic mechanisms of SARS-CoV-2 infection, and provides potential therapeutic targets and strategies.