Disruptions in the gut microbiota before transplantation associated with worse outcomes

<p class="article-intro">A new observational study reports that the likelihood of complications from a hematopoietic cell transplantation is higher if a patient has lower diversity of microbes residing in the gut before beginning the transplantation process. </p> <hr /> <p class="article-content"><p>Hematopoietic cell transplantation (HCT) is often used to treat aggressive blood cancers, but it can be associated with severe complications such as graft-versus-host disease (GVHD).</p> <p>The study was conducted in the United States, Europe and Japan and compared stool samples from nearly 1000 patients undergoing allogeneic HCT to those of healthy volunteers. Patients set to undergo HCT had gut microbiota that was 1,7- to 2,5-fold lower in diversity compared to healthy volunteers. The microbial communities in the majority of the patients&rsquo; guts went on to be dominated by a single bacterial species. While microbial composition, showed some variation from place to place, the diversity and types of microbes found in the stool of transplant patients in all countries was markedly different from those of the healthy volunteers. Further analysis showed this low diversity was associated with lower calorie intake, the use of broad-spectrum antibiotics, and the use of higher-intensity conditioning drugs to clear cancer cells from the body before transplantation.</p> <p>Patients with the lowest microbial diversity showed lower overall survival and a higher risk for GVHD.</p> <p>&bdquo;Before we approve patients to receive a transplant, we do many tests to make sure all of their organs are in good working order,‟ said lead study author Jonathan U. Peled, MD, PhD, of Memorial Sloan Kettering Cancer Center. &bdquo;In the future, we envision that the health of the gut microbiota &ndash; which some have called the forgotten organ &ndash; may become part of this whole-body evaluation. It might also be possible to intervene and repair the microbiota in the pre-transplantation period.‟</p> <p><strong>Reference:</strong><br />Peled JU et al.: Multicenter microbiota analysis indicates that pre-HCT microbiota injury is prevalent across geography and predicts poor overall survival. ASH Annual Meeting 2018, abstract #811</p></p>