An initial assessment of the immune phenotype of apoE KO mice revealed that these mice display splenomegaly (Fig. 1a, b) with an accumulation of CD4+CD44hiCD62Llo T cells (effector memory, TEM) but not of CD8+CD44hiCD62Llo in the spleen (Fig. 1c, d and Supplementary Figure 1A), and a concomitant decrease of CD4+CD44loCD62Lhi T cells (Tnaive). Here, APOE is linked to Splenomegaly.