IL17A and colitis: However, neutralization of IL-17 in dextran sulfate sodium colitis (DSS) aggravates disease [170], mice deficient for IL-23p19 are highly susceptible to T-cell dependent trinitrobenzene sulfonic acid (TNBS) colitis [171] and Il17a deficient CD45RBhi cells induce a more aggressive wasting disease in T-cell transfer colitis models [172].