IL6 and hemophagocytic syndrome: In addition to the HLH-2004 protocol, an anti–IL-6 antibody (tocilizumab) was FDA-approved in 2014 for HLH patients aged ≥ 2 years, as it results in rapid resolution of cytokine release syndrome in patients after chimeric antigen receptor (CAR) T cell or blinatumomab treatment [36].