Skin microbiome composition across time and microbial characteristics associated with 1-year mortality and aGVHD. (A) Microbial relative abundance over time across skin sites among HSCT patients, grouped according to 1-year mortality. (B) Community diversity using Shannon diversity index and correlation with survival and aGVHD. Statistical significance based on adjusted P values for unrestricted permutation are displayed. (C) Estimation of community stability within individuals using the BCI and association with 1-year mortality and aGVHD. An index of 0 means both samples share the same species at exact the same abundances; 1 means both samples have completely different species abundance. (D) Bray-Curtis dissimilarity in forearm microbial community between individuals. Statistical significance based on adjusted P values for unrestricted permutation are displayed. (E) Between-group forearm microbial community stability at pre-HSCT time point. Healthy controls represent caregiver controls. Two-sided Wilcoxon rank sum tests were used to test for significant differences between groups, and false discovery rate–adjusted P values are shown. FCB, fibrobacterota-chlorobiota-bacteroidota; mo, months; PVC, planctomycetes–verrucomicrobia–chlamydiae; wk, weeks.