DDIT3 and diffuse large B-cell lymphoma: Interestingly, while memory B‐cell responses to earlier vaccine antigen (tetanus toxin) were markedly diminished, hemagglutinin‐specific IgG‐secreting B cell responses could be stimulated by influenza vaccination in patients with DLBCL that had peripheral B‐cell depletion after completion of R‐CHOP.42