# Metataxonomic Analysis and Fatty Acid Profiling of Feces from Children Undergoing Hematopoietic Stem Cell Transplantation

## TL;DR

This study examines gut microbiome and fatty acid changes in children undergoing stem cell transplants, linking differences to GvHD outcomes.

## Contribution

The study identifies distinct gut microbiota and SCFA profiles in children with GvHD after HSCT.

## Key findings

- Fecal samples at engraftment showed reduced bacterial diversity and lower Blautia genus sequences.
- Children with GvHD had significantly lower butyrate and acetate concentrations compared to others.
- Microbiota and SCFA profiles differ in GvHD patients, suggesting potential for targeted prevention strategies.

## Abstract

Allogeneic hematopoietic stem cell transplantation (HSCT) is a medical procedure to treat hematologic malignancies and restore bone marrow function. However, this approach may lead to graft-versus-host disease (GvHD), a major cause of mortality and morbidity after allogeneic HSCT. Some studies have suggested the involvement of gut microbiota in the development and prognosis of GvHD. In this context, the main objective of this study was to compare the fecal microbiome composition and short-chain profile of pediatric patients who underwent successful HSCT, developed GvHD or died. The bacterial composition was analyzed using 16S rRNA gene sequencing, while short-chain fatty acids (SCFAs) were quantified by gas chromatography. Fecal samples at engraftment were mainly characterized by a loss of bacterial diversity, a depletion of sequences belonging to the genus Blautia and significantly lower concentrations of fecal butyrate and acetate compared with those obtained before HSCT and 100 days after HSCT. Our findings confirm that children experiencing GvHD after HSCT have distinct gut microbiota and SCFA profiles, which might contribute to developing new microbiota-targeted strategies for GvHD prevention during HSCT procedures.