In addition to the traditional calcineurin-dependent inhibitory effect on T cells, several studies have reported that the mechanism of tacrolimus-ameliorated colitis might be related to the suppression of activated macrophages (Yoshino et al., 2010; Cai et al., 2021), the restriction of dendritic cell migration and the subsequent differentiation of CD4+ T cells to Th1 and Th17 cells (Regmi et al., 2019), as well as protection against apoptosis-mediated intestinal epithelial injury (Satake et al., 2022). Here, CD4 is linked to colitis.