Effect of tumour necrosis factor (TNF) antagonist treatment on anti-mycobacterial responses. The effect of 14-week treatment with a TNF antagonist on the immune response against purified protein derivative (PPD) was determined in patients without a previous or latent tuberculosis group I (a), and in patients with a previous or latent tuberculosis group II (b). The effect of 14-week treatment with a TNF antagonist on the immune response against culture filtrate protein (CFP)-10 was determined in patients with a previous or latent tuberculosis group II (c). The thymidine incorporation, (PKH)-26 dilution, and enzyme-linked immunosorbent spot (ELISPOT) assays were performed, with results expressed (mean ± standard error of the mean) as stimulation indice (SI), fraction of proliferating cells (percentage), and number of interferon (IFN)-γ-producing cells per 106 cells. n = 31 in (a) and n = 25 in (b) and (c). *p < 0.01, **p < 0.005 for comparisons between week 14 and week 0 (Wilcoxon test).