PSEN1 and Alzheimer disease: To assess the involvement of B cells in AD, we first performed a flow cytometry evaluation of B cells in the circulation of congenic and sex- and age-matched C57BL/6 (WT) and 3×TgAD mice, a model for early-onset AD (EOAD, harbors the Swedish APP mutation, the M146V mutation on PS1 and the P301L in MAPT)24,25.