FFAR2 and graft versus host disease: We characterized the microbiota of allo-WT B6 animals and the allo-Gpr43−/− animals by 16S rRNA gene sequence analysis and found a significant difference between the bacterial communities of the two groups at day +14 post allo-BMT (p = 0.027, Fig. 2a) with increased representation of the phylum Proteobacteria, and decreased representation of the class Clostridia (Fig. 2a), consistent with previous reports of their correlation with GVHD severity.