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P845 The changes of intestinal microbiota composition may predict the response of anti-TNF α in patients with Crohn's disease

G. Seong*1, S. N. Hong1, T. J. Kim1, E. R. Kim1, D. K. Chang1, Y-H. Kim1

1Samsung Medical Center, Seoul, South Korea

Background

Crohn’s disease(CD) pathophysiology is thought to be associated with dysregulated mucosal immune response to gut microbiota. Infliximab can cause the improvement of disease activity and may be involved with the changes of intestinal microbiota. The aim of this study was to investigate the changes of intestinal microbiota composition during infliximab maintenance therapy and a relationship with mucosal healing in Korean CD patients.

Methods

A 16S rRNA sequencing was performed to analyse prospectively collected 35 faecal samples of 19 adult CD patients with clinical remission state. We obtained faecal samples twice at 1 week and 7 week after infliximab infusion and all the patients underwent endoscopy within last 3 months from enrolment to evaluate endoscopic mucosal healing(MH).

Results

Faecal microbial composition and biodiversity indexes did not significantly changed during infliximab infusion cycle. However, according to endoscopic MH, alpha diversity calculated by Shannon and Simpson index showed significant differences (p = 0.008, 0.001, resp.). In MH group, the relative abundance of phylum Firmicutes increased and Bacteroidetes decreased, also, there were significant differences in some genera, including Faecalibacterium, Prevotella, Blautia and Lactobacillus (p < 0.05).

Comparison of relative abundance

The principal coordinate analysis showed a clear separation between MH group and non-MH group.

PCoA plots between MH and non-MH group.

Using z-score analysis, non-MH group showed more unstable and chaotic changes of many bacterial taxa at order level over time after infliximab treatment.

Z-score analysis at order level.

Conclusion

We could not find meaningful changes between 1 week and 7 week samples, however, more diverse and stable bacterial community was observed in CD patients with mucosal healing. Some species (eg. Faecalibacterium prausnitzii) showed significant increase in patients with mucosal healing. The changes of intestinal microbiota might be used to predict the response to anti-TNF agents in CD patients.