In vitro effect of tumour necrosis factor (TNF) antagonists on membrane-bound TNF (mTNF) expression. In patients previously infected with TB (either from group II or IV), peripheral blood mononuclear cells were cultured alone (black shaded boxes), with purified protein derivative (PPD) (diagonally lined boxes), or with culture filtrate protein (CFP)-10 (horizontally lined boxes), and with infliximab (Ifx), adalimumab (Ada), etanercept (Eta), or a control antibody (-) (10 μg/ml each). (a) The TNF antagonist was added at the initiation of the culture, and mTNF expression on CD4+ T lymphocytes was determined on day 5 (n = 10). (b) The TNF antagonist was added on day 5 of culture, and mTNF expression on CD4+ T lymphocytes was determined 24 hours later (n = 7). Results (mean ± standard error of the mean) are expressed as the fraction of mTNF+ cells among CD4+ T lymphocytes. Paired comparisons were performed. *p < 0.05 (Wilcoxon test with Bonferroni corrections) for comparisons between cultures with Ifx, Ada, or Eta and cultures with the control antibody. (c) Results from a typical patient in the same conditions as in (b).