PRTN3 and rheumatoid arthritis: A previous study by Rooney et al examined the faecal 16S rRNA gene sequences of 25 asymptomatic ACPA-positive individuals and reported distinct feature as compared with 44 unrelated healthy controls (but no difference in Prevotellaceae).50 Beyond bacterial taxonomy, the faecal bacteriophage community of RA-FDRs was also assessed in a study by Mangelea et al, using a smaller sample size (25 individuals divided into 3 groups).51 The only cross-sectional study fully comparable with the present manuscript is a previous work from our group, in the same cohort.