IL17A and arthritic joint disease: H&E stained sections of wrists confirmed the absence of arthritis in IL-23 EEV injected B6 mice compared to the susceptible B10.RIII strain (Fig 4C), and there was no significant induction of Tnf, Il1b, Il17a or Il22 in the wrists of IL-23 EEV injected B6 mice (Fig 4D).