Anti-IL-6 receptor (eg, tocilizumab, sarilumab), anti-IL-6 (eg, clazakizumab, siltuximab) IL-6 Natural killer cells, T cells, B cells, endothelial cells Might help restore suppressed natural killer cell functions and oppose acute respiratory distress syndrome development IL-6 might have homoeostatic roles and induce SOCS3, IL-4Rα and CD163; conflicting preliminary results in severe–critical COVID-19; might favour bacterial, viral, and opportunistic infections (long half-life of IL-6 inhibitors)