CD28 and diffuse large B-cell lymphoma: We show here that CD4+ T cells were generated from naïve cells (CD45RO− CD45RA+) to an effector/memory (CD45RO+ CD45RA−) phenotype in patients with DLBCL, although the functional marker HLA-DR and the levels of costimulatory marker CD28 expressed by CD4+ and CD8+ T cells were not significantly elevated.