AICDA and influenza: Despite the age-related decrease in AID, influenza vaccine-specific memory B cells are maintained in the elderly after repeated vaccination with a vaccine containing the same H1N1pdm09, but the fold-increase in HAI titers after vaccination is lower in the elderly although most of them are seroprotected, suggesting that low seroconversion in the elderly may be mainly due to cell intrinsic defects in the differentiation of B memory cells to plasmablasts/antibody-secreting cells (ASCs) [71].