TNF and Arthritis: Following induction of mBSA/GM-CSF (Fig. 2a) and mBSA/TNF (Fig. 2b) arthritis in WT mice, as expected, pain developed by days 4 (P = 0.0081, 95% CI − 21.93, − 1.782) and 1 (P = 0.0007, 95% CI − 26.97, − 5.902), respectively [5, 9], which is not seen in the s.c. saline control group; arthritic pain was, however, not seen in Il23p19−/− mice in either of these models (Fig. 2a, b), indicating an IL-23 dependence.