Fecal microbiota analyses before and after treatment of lower GI aGVHD. (A) Overall microbiota composition in recipients of F-652 and corticosteroids (n = 22 patients) or corticosteroids alone (n = 27 patients). At baseline, microbial dysbiosis was present in all cohorts. Posttherapy, fecal samples from F-652 responders indicated an increased proportion of Lachnospiraceae. (B) PCA plots of microbial composition at baseline and following treatment. No distinct clusters can be found pretreatment in recipients of F-652 plus steroids or recipients of steroids alone. Samples clustering together in recipients of F-652 plus steroids following treatment are highlighted in the circle. (C) Comparison of β-diversity, focusing on PC2, prior to treatment and after GI GVHD treatment. (D) Abundance of Lachnospiraceae shown on the PCA plots of responders and nonresponders before and after GVHD treatment, highlighting enrichment of Lachnospiraceae in the previously identified cluster of F-652 responders. (E) Fold-change in Lachnospiraceae abundance following GVHD treatment, indicating Lachnospiraceae expansion in F-652 responders. (F) Fold-change in Blautia abundance following GVHD treatment, indicating Blautia expansion in F-652 responders. (G) Comparison of changes in Blautia abundance and overall microbial diversity indicates a correlation between the 2 parameters for GVHD patients responding to treatment with F-652 and steroids but not for patients treated with steroids alone.