In our studies with Mdr1a−/− mice, we noted that all T-cell subsets in draining MLN were decreased with anti-IL-7Rα M595 treatment, indicating that decreasing total T cells (which likely included CD4+IL-7Rαhigh cells) was in large part responsible for the lack of colitis seen in anti-IL-7Rα M595 antibody-treated mice. Here, CD4 is linked to colitis.