IL6 and colitis: Although the gene expression levels of inflammatory cytokines including interleukin (Il)6, Il17a, Il1b, and tumor necrosis factor-α (Tnfa) gradually increased with colitis progression in Sult2b1+/+ mice, these levels were considerably higher in Sult2b1+/− and Sult2b1−/− mice than those in Sult2b1+/+ mice on day 7 (Figure 2F).