Fig. 5

Association of plasma metabolite levels with RA disease status and gut microbiota. a A principal component analysis revealed that the overall metabolite profile differs between the RA patients and their first-degree relatives (FDR). Each point represents a sample colored by their group membership. The percentage of variance explained by corresponding principal components (PC) are shown on the axes. The direction and length of the blue lines indicates the contribution of the corresponding metabolites to the PCs. The ellipses represent a visual guide to group differences. b Differentially abundant metabolites between RA patients and FDRs (adjusted P < 0.05). The y-axis represents the standardized metabolite level. The error bars indicate the standard error of the mean. c A heat map shows the correlation between the abundances of the three genera Collinsella, Eggerthella, and Faecalibacterium and the differentially abundant metabolites. Colors indicate the Spearman rank correlation (**unadjusted P < 0.01, *P < 0.05, small black squares indicate P < 0.1). The differentially abundant metabolites show strong correlation with the abundance of Collinsella