CD4 and colitis: Inhibiting the ubiquitination of TRIM21 and the degradation of IRF3 in colitis induced by TRIM21-/-mice caused an increase in IL-17+CD4+ and IFN-γ+CD4+T cells, accompanied by an intensified immune reaction from CD4+T cells, culminating in heightened inflammation of the intestinal mucosa (33, 70, 71).