AB0168 IMBALANCE IN THE TAXONOMIC COMPOSITION OF GUT MICROBIOTA IN TAKAYASU ARTERITIS

Background Takayasu arteritis (TAK) is one form of the large vessel vasculitis and predominantly affects young female. TAK sometimes coexists with other inflammatory diseases which include ulcerative colitis (UC) spondyloarthropathy. Recent evidences revealed close genetic background between these diseases, we found common autoantibodies against endothelial protein C receptor among UC. These suggest underlying pathophysiology diseases. UC spondyloarthropathy are known to be associated dysbiosis. Therefore, involvement dysbiosis in pathogenicity possible. However, little regarding composition gut microbiota TAK. Objectives This study aimed investigate whether there existed imbalance taxonomic Methods 31 patients who satisfied classification criteria American College Rheumatology 1990 background-matched healthy controls (HC) were included this study. Feces collected from each individual, fecal microbial DNA was isolated. 16S rRNA gene amplicon sequencing performed analyze microbiota. Microbial richness β-diversity compared HC TAK, differences abundant taxa analyzed by LEfSe algorithm. Results The clinical group as follows; mean age, 41 years; female, 87%. disease activity assessed using Indian score (ITAS)-A, 17% an active status when they feces. Then, successfully extracted Shannon index, significant decrease (P=0.02). next investigated, approximately half clearly separated clusters HC. presence confirmed even condition most inactive status. Analysis microbiomes (ANCOM) showed abundance eight 10 genera HC, respectively cut-off centered log ratio 1. Cladograms changes microbiota, level phylum, class, order, family, genus related. Differential at observed a linear discriminant analysis threshold >2.0. Altered our enrichment Streptococcus, Lactobacillus, Veillonella, Enterococcus, Dialister, Actinomyces, Sardovia, Sellimonas, Rothia, Campylobacter. More numbers depleted Bacteroides, Phascolarctobacterium, Dorea, Parasutterella, Barnesiella, Acidaminococcus. Importantly, oral bacteria species documented Among them, two cases complicated infectious endocarditis during treatments tocilizumab, suggesting contribution for such complication Conclusion Significant diversity reduced altered relevant exacerbation inflammation. Dysbiosis could related inflammation complications References [1]Mutoh T, Shirai et al. Identification major autoantigens negatively regulating activation arteritis. Nat Commun. 2020;11(1):1253. [2]Shirai Kakuta Y, Fujii H. Distinct Autoantibodies Against Endothelial Protein Receptor Ulcerative Colitis. Gastroenterology. 2021;161(5):1724-5. [3]Kakuta Novel Diagnostic Patients With Clin Gastroenterol Hepatol. 2021; 3565(21)01359-8. Figure Acknowledgements: NIL. Disclosure Interests None Declared.