Synovial and circulating profiles of mediators displaying a sustained or late increase in their joint levels during antigen-induced arthritis. Expression of protein was assessed before the induction of antigen-induced arthritis (day 0) or afterwards (at 7 hours and on days 1, 2, 3, 7, and 14) in both arthritic (mBSA-injected) and contralateral (saline-injected) knees and in sera. Results are expressed as concentrations (in picograms per milliliter) in serum and as quantity by knee (in picograms per knee) of the proinflammatory cytokines interleukin-1-beta (IL-1β) (a), IL-18 (b), or IL-6 (c) and the T helper 2 cytokine IL-13 (d). Values are the mean ± standard error of the mean of five independent samples. *P < 0.05 in comparison with day 0. D, day; h, hour; mBSA, methylated bovine serum albumin.