SH2D1A and hemophagocytic syndrome: Autologous T-cell gene therapy would diminish concerns over ectopic SAP expression and has an established safety profile, with hundreds of patients treated to date for hematologic malignancies in cancer immunotherapy trials and no reported transformational events.13, 14, 15, 16, 17 Furthermore, important manifestations of XLP1, such as HLH, lymphoma development, and dysgammaglobulinemia, arise from defective T-cell function and would be potentially corrected through this approach.