IL6 and COVID-19: A study conducted at Humanitas Research Hospital in Rozzano (Milan, Italy) evaluated several baseline parameters on a large retrospective cohort of patients diagnosed with COVID-19, pointing out that the ratio of PaO2 to FiO2 (P/F), the lymphocyte count and the serum levels of C-Reactive Protein (CRP) and Interleukin 6 (IL-6) were associated with the risk of clinical deterioration [26].