Pre-transplant microbiome associations with development of cGVHD. Pre-transplant and Longitudinal Changes in Fecal Microbiome Characteristics Are Associated with Subsequent Development of Chronic Graft-versus-host Disease

The role of the gastrointestinal microbiome in predisposing to chronic graft-versus-host disease (cGVHD), an immune-mediated hematopoietic cell transplant (HCT) complication, is not well defined. We examined the relationship of the host fecal microbiome with subsequent cGVHD development by analyzing baseline stool samples as well as post-HCT changes in microbiome composition and metabolite pathway analyses. We analyzed pre-transplant baseline samples from 11 patients who subsequently developed cGVHD compared to 13 controls who did not develop acute or chronic GVHD at any time. A subgroup analysis of longitudinal samples within each patient was also completed. Our findings show a distinct pattern of baseline microbiome and metabolic capacity that may play a role in modulating alloreactivity in patients developing cGVHD.