Cytokine production by peripheral blood mononuclear cells stimulated with faecal samples from active CD patients, symptom free (SF) CD patients and healthy controls. 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.