The ageing human B cell repertoire: a failure of selection?

B cells undergo a number of different developmental stages, from initial formation of their B cell receptor (BCR) genes to differentiation into antibody-secreting plasma cells. Because the BCR is vital in these differentiation steps, autoreactive and exogenous antigen binding to the BCR exert critical selection pressures to shape the B cell repertoire. Older people are more prone to infectious disease, less able to respond well to vaccination and more likely to have autoreactive antibodies. Here we review evidence of changes in B cell repertoires in older people, which may be a reflection of age-related changes in B cell selection processes.