To elucidate the mechanisms underlying the reduction in CD4+ T cells induced by legumain deficiency, we performed transcriptomic profiling of CD4+ T cells isolated from the spleens of Lgmn−/−Apoe−/− mice and Lgmn+/+Apoe−/− mice. Here, APOE is linked to hyperinsulinemic hypoglycemia, familial, 4.