Allogeneic hematopoietic cell transplantation (allo-HCT) is an important treatment for many hematologic malignancies. While this therapy can be life saving for some patients with hematologic cancers, it can be associated with a complications, including infection, organ toxicity, and graft-versus-host disease (GVHD). The composition of the intestinal microbiota is a known factor influencing toxicity and outcomes following allo-HCT, but most studies have only evaluated intestinal composition in patients post-HCT.
At the 2018 American Society for Hematology (ASH) Annual Meeting, Jonathan Peled, MD (Memorial Sloan Kettering Cancer Center, New York, United States), presented results from a multicenter analysis that evaluated the association between composition of pretransplant intestinal microbiota in 1922 stool samples from 991 patients from three different geographic regions (United States, Europe, and Japan) and outcomes following allo-HCT.
In general, patients had 1.7- to 2.5-fold lower microbiota diversity prior to allo-HCT than healthy volunteers (P<.005). Interestingly, these results were similar across different geographic regions. The composition of pre-HCT microbiota differed from those of healthy volunteers and were not easily matched with known enterotype classifications. Lower microbiota diversity was associated with poor outcomes following transplant (HR 0.69; P = .002). Lower diversity of intestinal microbiota was associated most often with monodomination of some bacteria strains (eg, Enterococcus, Streptococcus, Lactobacillus, Escherichia, and Klebsiella taxa).
Dr Peled concluded that evaluation of patients’ microbiota prior to transplant may be helpful in guiding treatment decisions regarding antibiotic use, GVHD prophylaxis, and use of microbiota injury remediation strategies.