Cytokine production by peripheral blood mononuclear cells co-stimulated with faecal samples from either active CD patients or symptom free (SF) CD patients together with live bacteria of either Bifidobacterium longum ES1 and B. bifidum ES2. Panel A, TNF-α production; Panel B, IFN-γ production; Panel C, IL-10 production. Results are expressed as mean ± SD of duplicate measurements determined in four independent experiments. Significant differences between means were established by ANOVA with post hoc Fisher's least significant difference (LSD) test at P < 0.05. NS, not significant.