EBV-HLH can result from (1) HLH development secondary to EBV infection, in apparently EBV-immune individuals, (2) EBV infection where there is a genetic predisposition for lymphoproliferative disease (BIRC4 or SHD21A), (3) chronic active EBV infection, and (4) aggressive NK cell leukemia, and T/NK cell lymphoma [34,35,36]. The gene discussed is XIAP; the disease is hemophagocytic syndrome.