Synovial and circulating profiles of chemokines displaying an early 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-sensitized) 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 chemokines monocyte chemoattractant protein-1 (MCP-1) (a), growth-related oncogene/keratinocyte chemoattractant (GRO/KC) (b), regulated on activation normal T expressed and secreted (RANTES) (c), or eotaxin (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.