EBV reactivation in primary immunodeficiencies—such as interleukin-2-inducible t-cell kinase (ITK) deficiency, autoimmune lymphoproliferative syndrome (ALPS), and X-linked lymphoproliferative disease (XLP) [2,3]—remains possible, given their association with EBV-related HLH. This evidence concerns the gene ITK and X-linked lymphoproliferative disease.