TNF and COVID-19: Patients in stage IV of COVID-19 had significantly higher serum level of pro-inflammatory cytokines IL-1β (p = 0.001), TNF-α (p = 0.012) and IL-12 (p = 0.001) as well as immunosuppressive IL-10 (p = 0.001) compared to the patients in less severe stages of disease (Fig. 1A–D).