The present data reveal a great variability in the concentrations of calprotectin in stool samples collected during a single day. Since the levels of calprotectin increased with longer time between the bowel movements, it seems most appropriate to analyse stool from the first bowel movement in the morning. Moreover, storage of stool samples at room temperature for more than 3 days is not advisable.

IBS patients have an increased frequency of activated T cells, demonstrated by the expression of activation markers and reduced proliferation in response to restimulation in vitro. The increased level of T-cell activation is consistent with the hypothesis of low-grade immune activation in IBS and may also be involved in symptom generation in IBS.

Global cytokine profiles did not discriminate IBS patients from healthy subjects, but cytokine profiles were more varied among IBS patients than among healthy subjects, and a small subgroup of patients with enhanced immune activity was identified. Also, association of inflammatory cytokines with some clinical symptoms suggests that immune activation may be of importance in a subset of IBS patients.

No abstract