Gut microbiome reveals risk of organ rejection
Deviations in the gut microbiome could help assess the risk that a transplanted kidney will be rejected by the recipient’s immune system, and possibly even reduce this risk in the future. Researchers led Dr. Johannes Holle and Rosa Reitmeir have found that the gut microbial communities of kidney transplant patients showed distinct changes preceding organ rejection. The study was published in the “American Journal of Transplantation.”
Holle and Reitmeir as well as senior authors Dr. Nicola Wilck and Dr. Hendrik Bartolomaeus are part of the Immune-Microbial Dynamics in Cardiorenal Diseases lab headed by Wilck. The lab belongs to the Experimental and Clinical Research Center (ECRC), a joint institution of Charité – Universitätsmedizin Berlin and the Max Delbrück Center.
Other contributing authors of the study include: Professor Sofia Forslund, head of the research group Host-Microbiome Factors in Cardiovascular Disease at the Max Delbrück Center, Dr. Ulrike Löber from Forslund’s team as senior author, as well as other researchers from the Max Delbrück Center, Charité, and the German Center for Infection Research (DZIF).
In most patients, the microbiome recovered quickly
In their study, the scientists analyzed 562 stool samples from 245 participants in the DZIF transplant cohort. Since 2014, medical data and biological samples from participants in this cohort have been collected for research purposes at four sites in Germany: Hannover – Braunschweig, Heidelberg, Munich, and Tübingen. Of the 245 participants in the current study, 217 had received a donor kidney because of chronic kidney disease. The other 28 were healthy individuals who had donated a kidney.
The researchers found that in most patients, the microbiome – initially compromised due to kidney insufficiency – recovered after the transplant. This was evident, among other indicators, by an increase in the Shannon Index, which measures the diversity of biological communities.
Biodiversity in stool dropped prior to rejection
In patients whose immune systems had rejected a donor kidney, the researchers observed a decrease in microbial diversity. Notably, even before the organ rejection process was clinically diagnosed, the number of bacteria that produce such short-chain fatty acids as propionate and butyrate had declined. These acids perform many important functions in the body. At the same time, the quantity of bacterial enzymes responsible for producing these fatty acids also dropped. The microbiome characteristics they examined normalized again after the rejection event.
“Our results suggest that the microbiome plays a role in determining how the immune system responds following a kidney transplant,” say Holle and Reitmeir. Their observations could help detect the risk of rejection early and potentially even point to new therapeutic approaches in the future.
In Germany, the kidney is the most commonly transplanted organ. For patients with advanced kidney failure, the procedure remains the best treatment option. According to the German Organ Transplantation Foundation, more than 1,500 people in Germany receive a donor kidney each year.
Further information
Literature
Johannes Holle, Rosa Reitmeir et al. (2025): “Gut microbiome alterations precede graft rejection in kidney transplantation patients.” American Journal of Transplantation, DOI: 10.1016/j.ajt.2025.02.010
