Literature on the use of tocilizumab for HLH/MAS was reviewed by the EBG workgroup, including the impact of IL-6 on NK cell function [24, 25], rates of MAS in sJIA patients treated with tocilizumab [9, 50, 51], use of tocilizumab to treat MAS in sJIA and Adult-onset Still’s disease (AOSD) [52, 53], and efficacy of tocilizumab in cytokine release syndrome secondary to T cell engaging oncologic therapies [54, 55]. Here, IL6 is linked to macrophage activation syndrome.