CD4 and post-transplant lymphoproliferative disease: Such a lack of latent EBV-specific CD4+ T cells has been identified in various types of non-Hodgkin lymphoma (NHL) in human immunodeficiency virus (HIV)-patients[35] and in immunocompetent individuals with EBV-related lymphoma,[36] as well as in one transplant patient with EBV-related PTLD.[37] In addition, prolonged EBV-seronegativity has been observed in solid organ transplant recipients who develop early-onset EBV+PTLDs.[38] Altogether, these data suggest that defective EBV-specific CD4+ T cell immunity could favor NHL development and particularly PTLDs.