Markers of bacterial translocation as a possible indicator of subclinical inflammation in pediatric inflammatory bowel diseases patients

Introduction
Recently there has been significant progress in research on the pathogenesis of inflammatory bowel diseases (IBD).

Aim
Our study aimed to assess selected markers of bacterial translocation in children with IBD in relationship to disease activity.

Material and methods
Lipopolysaccharides (LPS) – markers of bacterial translocation – and proinflammatory cytokines – interleukin (IL)-8, IL-12 and tumor necrosis factor (TNF)  – were assessed in the serum of 27 pediatric IBD patients at the outbreak of the illness and then 1 and 3 months after the introduction of the treatment. The analyzed markers were taken once in 6 healthy children in the control group.

Results
Serum TNF- and LPS concentrations were significantly higher in IBD patients than in the control group (1.74 vs. 0.83 ng/ml and 21.83 vs. 10.26 pg/ml, p < 0.05). In the study group, clinical and laboratory activity mediators significantly decreased during 3 months of the treatment. All proinflammatory cytokines decreased, but significant down-regulation was observed only in relation to IL-12 (129.21 vs. 82.98 pg/ml, p < 0.05) in CD and IL-8 (32.72 vs. 20.97 pg/ml, p < 0.05) in UC patients. TNF- levels decreased but did not reach values as in healthy children, while LPS levels increased in both groups.

Conclusions
IL-12 in CD and IL-8 in UC could be non-invasive markers of reduced inflammation during IBD in children. Improvements in clinical status and reductions in systemic inflammatory markers do not necessarily mean complete cessation of the inflammatory cascade. The elevated TNF- and LPS levels found in patients in early remission may be a marker of subclinical inflammation.