CD4 and post-transplant lymphoproliferative disease: T cell co-culturing with lymphoblastoid cell lines (LCL) from EBV-infected human peripheral blood B cells induces CD4+ CTLs and CD8+ CTLs, providing efficient adoptive cell immunotherapy for patients with EBV-associated malignancies such as Hodgkin’s lymphoma, nasopharyngeal carcinoma, and post-transplant lymphoproliferative disease (PTLD) [14], suggesting a possible role of EBV-induced CD4+ CTLs in controlling EBV-associated diseases.