Intestinal microbiota in patients with acute leukemia (AL) and allogeneic hematopoietics stem cell transplantation (allo-HSCT).

Abstract

e19518 Background: Microbiome is a challenging study area due to its influence on the multiple host functions. The majority of human-associated microbes reside within the colon. Our understanding about the complex interplay between host and environmental factors to shaping the microbiota is evolving rapidly AL is an unfavorable prognosis disease whose only cure possibility is the allo-HSCT. This procedure uses high doses of chemotherapy and multiple drugs such as antibiotics, antiviral, antifungals, and immunosuppressants that damage the mucous membranes and alter the intestinal microbiome balance. These events have been linked to bacterial resistance, relapse risk, Graft Versus Host Disease (GVHD), and poor Overall Survival (OS). The present study’s objective was to identify the intestinal microbiome bacteria groups during allo-HSCT and to evaluate their impact on patients outcome. Methods: Observational and prospective study was performed. Eleven patients with acute leukemia under alloHSCT and 11 health control (relatives) were enrolled. Gut faecal samples were collected in both groups; three for patients (at income day (ID), neutropenic period (N) and 30 days after discharge (+30D) and one in healthy donor (HD) at income day of their relatives. Bacterial 16S rRNA gene sequences were characterized by illumina and QUIIME 2. Biodiversity of microbiome was evaluated by OTUS, Shannon index and dominance. This proyect was supported by CONACyT. Results: We analyze 11 patients, 55% were male, with a median of 25 years-old at allo-HSCT. 7/10 received a HLA-identical and 4/10 an haploidentical HSCT. 82% had GVHD (I-IV), 1/11 died (two due to infections-GVHD and one of disease relapse). We analyzed 44 samples. There are no difference between healthy control group and income day patients’ samples. Statistical differences in the patients’ microbiome were identified among HSCT moments. According OTUS and Shannon Index the biodiversity decrease at neutropenia, and increase at day +30 outcome but it doesn’t represent a complete recovery. Greater bacterial dominance was observed in neutropenia period. (Table). 3/10 patients who died didn’t recovery biodiversity at day +30. Conclusions: Our results suggest that poor microbiome biodiversity recovery could be a worst prognostic [Table: see text]