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* = Presenting author

P381 Feasibility and value of stool anti-TNF measurement in IBD patient in loose of response: a preliminary study

S. Paul1, M. Rinaudo1, C. Jarlot2, E. del Tedesco2, J.M. Phelip2, X. Roblin*2

1University of Saint Etienne, Immunology, Saint Etienne, France, 2University Hospital, Gastroenterology, Saint Etienne, France

Background

In a preliminary study including 11 patients with severe UC on IFX induction treatment, the authors found an association between faecal IFX levels, a drop in circulating IFX trough levels (TLI) and treatment non-response. To our knowledge, no studies have been carried out on faecal anti-TNF levels (IFX and ADA) in cases of loss of therapeutic response in UC and CD patients. The aim of this preliminary study was to assess the feasibility of this test in determining faecal anti-TNF levels (IFX and ADA) in the two types of IBD and to investigate whether this correlates with clinical or endoscopic activity.

Methods

Retrospective study were including from a clinical database and from biological collection data, the first 36 IBD patients with faecal calprotectin levels above of 1800µg/g stools. Faecal anti-TNF assays were conducted on all of these patients and compared with the results of 6 IBD patients with a faecal calprotectin level below 500µg/g (below 500µg/g in 3 cases and below 100µg/g in the other 3 cases). At the same time, we analysed trough levels of anti -TNF and antibodies. All measurements were obtained just before infusion or injection of anti TNF drugs. Exclusion criteria were severe acute colitis and patients under anti TNF therapy under induction regimen.

Results

42 samples were analysed (20 CD, 22 cases on IFX treatment). The 36 patients with faecal calprotectin levels > 1800 µg/g exhibited clinical activity. An anti-TNF (> 0.2µg/ml of stools ) was reported in 7 cases. In 5 cases, the patient was treated with IFX (22.7%) and in two cases with ADA (10%) (p: NS). Anti-TNF was found to be present in stools in 5 cases of UC (22.7%) and in two cases of colonic Crohn's disease (10%) (p: NS). A positive anti-TNF threshold of stools was only isolated in cases where calprotectin was over 1800µg/g (19.4%). No correlation to clinical activity or response to optimisation was reported among patients with or without faecal anti-TNF. Circulating anti-TNF levels at the time of the measurement were higher for IFX and ADA in the presence of feacal anti-TNF. In the 7 cases showing faecal anti-TNF, an endoscopy detected ulcers in the colonic mucosa (100%) as compared with 5 /29 colonic diseases showing ulcers in the absence of faecal anti-TNF (14%, p<0 .05).

Conclusion

Excluding severe colitis and induction regimen, feacal anti-TNF can be detected in cases of CD as well as UC, irrespective of the anti-TNF used. The presence of colonic ulcers appears to be a pre-condition of intestinal leaks which inversely have no effect in these cases on circulating anti-TNF levels. Large-scale prospective studies would better determine the potential value of this new parameter in IBD patients.