23 Jun Microbiome Affects the Immune System of Transplanted Organs
MedicalResearch.com Interview with:
Dr. Maria Luisa Alegre
Maria-Luisa Alegre, MD, PhD
Professor of medicine
University of Chicago
MedicalResearch.com: What is the background for this study? What are the main findings?
Response: Most of the research that investigates why/how transplanted organs are rejected has focused on the genetic disparities between the donor and the recipient. Foreign proteins in the donor organ are recognized by the immune system of the host, which becomes activated to reject the transplanted organ. This is why transplant recipients need to take immunosuppressive medications for the rest of their lives.
Whether environmental factors, in addition to genetic factors, can also affect how the immune system is activated by the transplanted organ is much less understood. In particular, the microbiota, the communities of microbes that live on and in our body, is distinct in each individual and is known to affect the function of the immune system in diseases ranging from autoimmunity to cancer.
Using mouse models of skin and heart transplantation, we investigated if the microbiota was an environmental factor that could affect the speed at which the immune system rejects a transplanted organ.
We found that the microbial communities that colonize the donor and the host fine-tune the function of the immune system and control the strength with which the immune system reacts to a transplanted organ.
MedicalResearch.com: What should readers take away from your report?
Response: The specific communities of microbes that colonize each individual can affect how strongly the immune system reacts to a transplanted organ.
However, it would not be advisable at this point to recommend probiotics, or for patients to attempt to change their microbiota. We have evolved to cohabit effectively with our microbes, and they are very beneficial, making vitamins we need, digesting foods we would not be able to digest, or helping fight infections. Changing the composition of the microbiota in patients with particular genetic susceptibilities carries the risk to trigger autoimmunity or other diseases. Particular bacterial species may affect distinct individuals differently, depending on their genetic makeup.
MedicalResearch.com: What recommendations do you have for future research as a result of this study?
Response: More basic research is needed to determine which particular microbial species promote transplant rejection and whether particular species can promote better transplant survival. Clinical research is needed to determine how applicable to humans are our results in the mouse. We also need to understand how certain microbial communities communicate with the immune system to drive transplant rejection. We hope eventually to develop therapeutic recommendations.
MedicalResearch.com: Is there anything else you would like to add?
Response: Understanding the intra-community relationships of the microbiota is also crucial, as specifically adding or eliminating a species through probiotics or targeted antibiotic treatment, respectively, could affect the healthy balance of microbial communities and change the susceptibility to diseases among individuals.
MedicalResearch.com: Thank you for your contribution to the MedicalResearch.com community.
Citation:
Yuk Man Lei, Luqiu Chen, Ying Wang, Andrew T. Stefka, Luciana L. Molinero, Betty Theriault, Keston Aquino-Michaels, Ayelet S. Sivan, Cathryn R. Nagler, Thomas F. Gajewski, Anita S. Chong, Caroline Bartman, Maria-Luisa Alegre. The composition of the microbiota modulates allograft rejection. Journal of Clinical Investigation, 2016; DOI: 10.1172/JCI85295
Note: Content is Not intended as medical advice. Please consult your health care provider regarding your specific medical condition and questions.
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Last Updated on June 23, 2016 by Marie Benz MD FAAD