A range of agents antagonizing common pro-inflammatory mediators such as IL-1 (anakinra) and IFN-γ (emapalumab) may be employed to aid remission in primary HLH, whilst specific aetiologies where IL-18 hyperactivation is implicated may benefit from IL-18 binding protein analogues (42–45). The gene discussed is IL18; the disease is hemophagocytic syndrome.