Abnormal immune regulation in children with irritable bowel syndrome.

Irritable bowel syndrome (IBS) is regarded as a multifactorial disorder, but there has been evidence over the last few years leading to the proposal of the presence of abnormal immune regulation due to a decrease in anti-inflammatory cytokines and an increase in the proinflammatory ones. For example, a systematic review suggested the presence of low levels of IL-10 in blood with increased levels of proinflammatory cytokines, even though the results were inconsistent. In a recent meta-analysis by Bashashati et al. that analyzed IL-10 and TNFlevels, no differences were found in IL-10 between subjects with IBS and controls. However, upon analyzing differences in relation to sex, IL-10 levels were lower in men with IBS vs men in the control group. Furthermore, TNFlevels tended to be higher in the IBS subjects, compared with the controls. In IBS, increased proinflammatory cytokines derived from peripheral blood mononuclear cells (PBMC) have also been shown in both the baseline period, as well as after bacterial lipopolysaccharide (LPS) stimulation. In addition, lower IL-10 mRNA expression in the colonic mucosa has been reported in patients with IBS vs healthy controls. Nevertheless, all these data are from studies carried out on adults. In this issue of the Revista de Gastroenterología de México, Vázquez-Frias et al. published what is perhaps the first study on the pediatric population that analyzes the free plasma levels of anti-inflammatory and proinflammatory cytokines in Mexican patients with IBS based on the Rome III criteria, compared with healthy controls.