Conference Coverage

Low microbiota diversity linked to poor survival after transplant



– A multicenter study confirmed that diversity of gut microbiota is associated with better survival after allogeneic hematopoietic cell transplantation (HCT), while low diversity and the predominance of pathogenic bacteria are linked to graft versus host disease (GVHD).

Lower calorie intake and exposure to broad-spectrum antibiotics were both associated with lower diversity, the study found.

“One of the striking findings early on was this association between diversity in the gut and overall survival,” said Jonathan Peled, MD, PhD, noting that his research group also saw that high gut diversity was associated with lower rates of GVHD-related mortality.

“The first question that I want to ask today is ‘Are the patterns of microbiota injury that have been described in single-center studies and their association with clinical outcomes consistent across geography?’” Dr. Peled said during a top abstracts session at the combined annual meetings of the Center for International Blood & Marrow Transplant Research and the American Society for Blood and Marrow Transplantation.

To answer this, Dr. Peled and his associates at Memorial Sloan Kettering Cancer Center (MSKCC), New York, teamed up with a research group at Duke University, Durham, N.C., and with investigators in Regensburg, Germany. The international group devised a study that would use centralized sequencing and analysis to examine patient fecal samples from all three centers.

In all, 5,310 samples were obtained from 1,034 HCT patients. MSKCC contributed most of the samples (n = 908, 87.8%), with Regensburg contributing 79 (7.6%) and Duke contributing 47 (4.5%).

The most common malignancies treated were acute myeloid leukemia, myelodysplastic syndrome, and non-Hodgkin lymphoma. The balance of graft sources and conditioning intensity varied between centers, but overall, more than three-quarters of grafts were from peripheral blood stem cells and just over half of patients received myeloablative conditioning.


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