XIAP and Epstein-Barr virus infection: Marsh [23] reported that 30% of ten XIAP-deficient patients with HLH were EBV-positive, while in a Japanese cohort, four of six (66.7%) XIAP-deficient patients presenting with HLH were associated with EBV, and the EBV infection rate was as high as 81.8% (27/33) in SAP-deficient patients [19].