Stool and blood specimen collection
BLOOD
Stool specimens were collected from the study participants at baseline before conditioning (day −7), nadir (approximately days 5–7), engraftment (approximately day 14) and day 100 using a collection device that allows for microbiome and metabolome analyses (OMNIgene container, Genotek). After processing, stool specimens were stored at −80 °C. If patients were able to provide weekly samples, then stool was collected and analyzed weekly; however, stool was also collected at the four aforementioned time points which were prespecified and required for the blood specimens: baseline; nadir; engraftment; and day 100. Blood specimens were collected using standardized protocols in EDTA tubes at baseline (day −7), nadir (approximately days 5–7), engraftment (approximately day 14) and day 100. Samples were processed within 24 h to plasma and PBMCs. After processing, blood specimens were stored at −80 °C.