Alpha diversity and graft-versus-host disease (GVHD). A, Balanced weighted phylogenetic diversity (BWPD) and inverse Shannon (InvSh) species diversity. The top row is for all observed time points; the bottom row is only for samples closest to neutrophil recovery. Alpha diversity was statistically significantly lower in those with severe GVHD (P < 0.05) as calculated by general estimating equations with independence as a correlation structure when all time points are considered. B, A receiver operator characteristic for BWPD (dashed blue) and InvSh (solid orange) at neutrophil engraftment as a test for subsequent development of severe (grade 3–4) acute GVHD. Abbreviations: AUC, area under the curve; BWPD, balanced weighted phylogenetic diversity; GVHD, graft-versus-host disease; HCT, hematopoietic cell transplantation; InvSh, inverse Shannon; ROC, receiver operator characteristic.