CSF2 and colitis: In contrast, pathogenic Th17 cells, also known as colitis-causing T cells, can release large amounts of the pro-inflammatory cytokines IL-17, IL-6, IL-22, TNF-α, IFN-γ, and GM-CSF (granulocyte-macrophage colony stimulating factor) after being activated by IL-23 and IL-1β, and can also help to promote the production of Th1 cells, further aggravating intestinal inflammation (Harbour et al., 2015; Honda and Littman, 2016; Jain et al., 2016).