To understand the mechanism that underlies the exacerbation of DSS-induced colitis in TRAF5-deficient mice, we examined the mRNA levels of typical cytokines and transcription factors associated with Th1 (TNF-α, IFN-γ, and T-bet), Th2 (IL-4 and GATA-3), and Th17 (IL-17a, IL-22, ROR-α, and ROR-γt) cells by qRT-PCR. This evidence concerns the gene IL17A and colitis.