CD4 and lymphoproliferative syndrome: In immunosuppressed hematopoietic stem cell transplant (HSCT) recipients, such EBV-positive post-transplant lymphoproliferative disorders have been successfully treated by the infusion of polyclonal EBV-specific T-cell preparations that are generated by repeated stimulation of peripheral blood T cells with autologous EBV-infected B cells (LCL) in vitro and contain CD8+ and CD4+ T-cell components [4]–[6].