Expression of mRNA of various cytokines in the synovial membrane of rats with AIA. Expression of mRNA was assessed before the induction of antigen-induced arthritis (AIA) (day 0) or afterwards (at 6 hours and on days 1, 3, and 6). Data were originally expressed as arbitrary units (1 unit = highest detectable dilution of the competitor fragment) and then related to the value of day 0 (fold change). Values are means;vertical bars indicate the standard error of the mean (n = 4 to 6 rats for each time point). Each determination was performed in duplicate. *P ≤ 0.05, **P ≤ 0.01 in comparison with day 0; +P ≤ 0.05, ++P ≤ 0.01 in comparison with the preceding date.