Microbes matter in pediatric allo-HSCT

In this issue of Blood, Masetti et al(1) report on the findings of a multicenter observational study that explored the role of the microbiome in pediatric allogeneic hematopoietic stem cell transplantation (allo-HSCT). They studied 90 children and found that patients with high fecal microbial diversity prior to allo-HSCT had longer overall survival and a lower incidence of acute graft-versus-host disease (GVHD) compared to patients with low microbial diversity. In adult allo-HSCT recipients, high pretransplant fecal diversity has also been positively correlated with overall survival. Importantly, a key difference between this pediatric study and prior analyses in adults is that in this work, the perineutrophil-engraftment microbiome was not associated with outcome, whereas intestinal microbial features during this time window have been shown to predict outcome in adults (see figure).

Automated summary

This study found that pediatric allo-HSCT patients with high microbial diversity prior to transplantation had longer overall survival and a lower incidence of acute GVHD. This is consistent with previous findings in adult allo-HSCT recipients. However, a key difference in this study is that the post-neutrophil engraftment microbiome was not associated with outcome, unlike in adults.