Fig. 4: Donor-specific FMT effects on acute graft-versus-host disease risk.

a Principal coordinate analysis using Aitchison’s distance, comparing post-FMT samples between patients developing vs. not developing grade III–IV aGVHD. The first two principal coordinates (PC1 and PC2) are shown. Numbers in parentheses indicate percent variation explained by the corresponding axis. Each symbol represents a sample. The centroid of each cluster is shown by a larger symbol. Confidence ellipses are shown. The P value is from an adonis test with 999 permutations. b Same analysis as in (a), this time comparing post-FMT samples from different donors. Overall P = 0.00002. P values for all pairwise comparisons were <0.05. c Volcano plot showing post-FMT species associated with subsequent grade III–IV aGVHD in differential abundance analysis using general linear model-based Microbiome Multivariable Association with Linear Models (MaAsLin2). Each circle is a species; those with FDR-adjusted P value (q value) <0.10 are shown as larger circles in red. The significance threshold is shown as a dashed blue line. Circles above this line represent statistically significant species. All species significant at this threshold were also significant at q < 0.05. All significant species are to the right of zero along the x axis, indicating their association with grade III–IV aGVHD. d Relative abundance (y axis) of significant species in (c) in post-FMT samples compared between patients developing vs. not developing grade III–IV aGVHD. Each box shows the median (horizontal middle line) and interquartile range. Whisker lines indicate non-outlier maximum and minimum values. A small horizontal jitter is included for better visualization. Adjusted P values (q values) are from (c) and two-sided. Data from 3 and 14 patients with and without grade III–IV aGVHD are included, respectively. aGVHD acute graft-versus-host disease, FMT fecal microbiota transplantation, PC principal coordinate.