Fig. 2.

Anti-tumour necrosis factor (TNF) treatment with adalimumab and etanercept leads to an increase in frequency of circulating T helper type 17 (Th17) cells in peripheral blood. The kinetics of change of circulating interleukin (IL)-17-producing cells during anti-TNF treatment were the same in rheumatoid arthritis (RA) patients treated with etanercept (n = 18) (a) and with adalimumab (n = 7) (b), as determined by IL-17 enzyme-linked immunospot (ELISPOT) assay; 200 000 PBMC were seeded in triplicate in each experiment and stimulated with 1 μg/ml anti-CD3 antibody for 20 h and the numbers of cytokine-producing cells were enumerated. The percentages of circulating CD4⁺IL-17⁺ cells in the peripheral blood of RA patients increased similarly in patients treated with etanercept (n = 18) (c) and adalimumab (n = 7) (d). Bars represent mean ± standard error of the mean (s.e.m.). *P < 0·05, **P < 0·01 versus baseline visit by Wilcoxon's matched-pairs test. spSFC/10⁶ = specific spot-forming cells per million PBMC.