Our body has immune cells which look out for and protect against dangerous organisms like viruses. In COVID-19, researchers are beginning to understand how viruses hiding from the immune system can later make disease more severe [1–6]. If cells are too late to see SARS-CoV2, the virus is free to spread throughout the body. Eventually there are so many viruses, that they can no longer hide from the immune system [7,8]. The immune system begins to combat the spreading virus, turning on protein communication systems called cytokines to coordinate their response. Cytokines are communication proteins that are key for immune responses and are secreted throughout the body following viral detection. However, too many of these cytokine signals can also damage our own body [9,10]. Thus, researchers are now trying to better understand ways in which they can use cytokines to support immune responses against COVID, while also stopping out-of-control cytokines in patients with severe COVID-19 [10–12].
1. Blanco-Melo, D. et al. Imbalanced Host Response to SARS-CoV-2 Drives Development of COVID-19. Cell 181, 1036–1045.e9 (2020).
2. Lei, X. et al. Activation and evasion of type I interferon responses by SARS-CoV-2. Nat. Commun. 11, 1–12 (2020).
3. Thoms, M. et al. Structural basis for translational shutdown and immune evasion by the Nsp1 protein of SARS-CoV-2. Science (80-. ). 8665, eabc8665 (2020).
4. Hadjadj, J. et al. Impaired type I interferon activity and inflammatory responses in severe COVID-19 patients. Science (80-. ). 724, eabc6027 (2020).
5. Vabret, N. et al. Immunology of COVID-19: current state of the science. Immunity (2020). doi:10.1016/j.immuni.2020.05.002
6. Mathew, D. et al. Deep immune profiling of COVID-19 patients reveals distinct immunotypes with therapeutic implications. Science (80-. ). 8511, eabc8511 (2020).
7. To, K. K. W. et al. Temporal profiles of viral load in posterior oropharyngeal saliva samples and serum antibody responses during infection by SARS-CoV-2: an observational cohort study. Lancet Infect. Dis. 20, 565–574 (2020).
8. Wang, Y. et al. Kinetics of viral load and antibody response in relation to COVID-19 severity. J. Clin. Invest. (2020). doi:10.1172/JCI138759
9. Lucas, C. et al. Longitudinal analyses reveal immunological misfiring in severe COVID-19. Nature (2020). doi:10.1038/s41586-020-2588-y
10. Giamarellos-Bourboulis, E. J. et al. Complex Immune Dysregulation in COVID-19 Patients with Severe Respiratory Failure. Cell Host Microbe 27, 992–1000.e3 (2020).
11. Wang, N. et al. Retrospective Multicenter Cohort Study Shows Early Interferon Therapy Is Associated with Favorable Clinical Responses in COVID-19 Patients. Cell Host Microbe 1–10 (2020). doi:10.1016/j.chom.2020.07.005
12. RECOVERY Collaborative Group et al. Dexamethasone in Hospitalized Patients with Covid-19 – Preliminary Report. N. Engl. J. Med. 1–11 (2020). doi:10.1056/NEJMoa2021436
