CD4 and inflammatory bowel disease: The main results of the present study are as follows: (1) Significant increases in HIF-1α were seen in the inflammatory CD4+ T cells of the IBD model mice that were isolated from a secondary lymphoid tissue, the spleen (Figure 1), (2) the HIF-1-mediated up-regulation of K2P5.1 was seen in stimulated CD4+ T cells (Figure 2, Figure 3, Figure 5 and Figure 6), and (3) no involvement of the class III HDAC, SIRT1, was in the post-translational modifications to K2P5.1 in these cells (Figure 7).