Gut microbiota composition in untreated people with relapsing-remitting and secondary-progressive Multiple Sclerosis (P2-3.008)

Abstract

<h3>Objective:</h3> To investigate prospectively the qualitative&amp;quantitative differences in the faecal bacterial composition of untreated patients with RRMS and SPMS. <h3>Background:</h3> Alterations in gut microbiome composition are suggested to act as a driver in the transition of RRMS to secondary-progressive MS (SPMS). <h3>Design/Methods:</h3> We present prospective 16S rRNA gene high-throughput sequencing data from faecal samples of 33 patients with RRMS and 10 patients with SPMS. Differences between gut microbiota composition were validated prospectively at three time-points over 12-months. We used available microbial profiles of healthy controls and RRMS from a different population (Jangi-et-al.2016) for comparative analyses with our own data. We studied blood T regulatory cell (CD4+CD25highFoxp3+) associations with specific gut bacterial taxa. <h3>Results:</h3> While some gut microbiota composition traits were common to RRMS and SPMS patients, we identified a small number of distinctive bacteria associated with SPMS; of these, the genus Slackia. Slackia exigua is known to be part of gut dysbiosis associated with cancer progression. There were no significant correlations between Treg counts and abundance of selected bacterial taxa significantly associated with RRMS or SPMS. <h3>Conclusions:</h3> Subtle differences were observed between the gut bacterial composition of SPMS patients and that of RRMS. <b>Disclosure:</b> Dr. Tanasescu has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Johnson &amp; Johnson Romania. Dr. Tanasescu has received research support from UK MRC grant MR/T024402/1. The institution of Ms. Cortés Carbonell has received research support from Royal Society. David Pritchard has nothing to disclose. Prof. Cantacessi has nothing to disclose. Dr. Constantinescu has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Biogen. Dr. Constantinescu has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Roche. Dr. Constantinescu has received personal compensation in the range of $500-$4,999 for serving as an Expert Witness for Novartis. The institution of Dr. Constantinescu has received research support from Nottingham University Hospital Charity.