Dynamic Variations in Gut Microbiota in Ankylosing Spondylitis Patients Treated with Anti-TNF-α for Six Months

Ankylosing spondylitis (AS) is known as a microbiome-driven disease; however, the current understanding of microbiota dynamics in AS is limited. In the present study, we conducted a 16S rDNA sequence-based microbiota survey of 97 fecal samples from healthy subjects and AS patients at baseline, 1, 3 and 6 months after anti-TNF-alpha treatment to demonstrate the dynamic characteristic variations of gut microbiota in AS patients. The goal of this experiment is to explore the values of gut microbiota as biomarkers of disease activity and therapeutic responses to anti-TNF-alpha. We found that the relative abundance of microbiota in AS patients treated with anti-TNF-alpha differed at various time points and distinguished 4 groups: the higher and lower than healthy control (HC) level groups throughout the study and the unchanged and restored to HC levels groups. The characteristic increases of microbes in AS patients were f_Prevotelkceae and f_Actinomycetaceae. In HC, the characteristic increase was f_Lachnospiraceae. BASDAI positively correlated with the relative abundance of g_Escherichina-Shigella and g_Klebsiella, but negatively correlated with f_Lachnospinimaae at baseline. (r=0.544, P=0.013, r=0.509, P=0.022 and r=-0.577, P=0.008, respectively). The beta-diversity of microbiota in AS at baseline was lower than HC at the same level (P<0.01) and restored to normal values one month after treatment. In conclusion, the variation of gut microbiota is dynamic. Therefore, some microbes can be used as indicators for monitoring disease activity and therapeutic responsiveness during treatment.