Virus infection supports organ acceptance

A question of tolerance: Liver transplants in patients with hepatitis C

2014-06-26

(Press-News.org) This news release is available in German.

Over 150 million people throughout the world suffer from chronic infection with the hepatitis C virus (HCV), which causes massive damage to the liver. Advanced liver diseases often necessitate liver transplants. In the new clinical study Dr. Felix Bohne and his colleagues studied together with Prof. Alberto Sánchez-Fueyo from King's College London 34 hepatitis C patients at the Liver Unit of the University Hospital Clínic de Barcelona who had received new livers.

The researchers had two objectives here: first, they wanted to gain a better understanding of the mechanisms that enable the body's own immune system to tolerate the new organ despite the HCV infection; second, they were looking for factors that could act as biomarkers for tolerance in the patients.

"If tolerance could be reliably predicted based on certain markers, many patients could stop taking immunosuppressants after a certain period of time," explains Dr. Felix Bohne, lead scientist of the study. Patients must take these strong drugs after transplants. They suppress the immune system so that the body does not identify the new organ as foreign and reject it. For patients with hepatitis C, this is a particular burden, as they need a stable immune system after the transplant to control their chronic HCV infection.

Markers for tolerance

During the study, the patients stopped taking the immunosuppressants. They were observed for twelve months to see which of them could also tolerate the new organ without the drugs, and which of them did not. The scientists took liver and blood samples from the patients prior to and after the cessation of the drugs. Detailed immunological tests on these patient samples were carried out under the leadership of Prof. Ulrike Protzer of the "Immunmonitoring Platform" at the Institute of Virology. The scientists compared the patients with each other and looked for any differences that arose in tolerant patients only.

And the scientists struck gold: a certain group of genes was very active only in the livers of tolerant patients. The genes in question belonged to the type I interferon system, which targets viruses like HCV as part of the innate immune system. As the results showed, an anti-viral mechanism does actually enable the patients to better tolerate a foreign organ.

Ulrike Protzer provides a possible explanation for this: "When the interferon system is constantly activated as is the case in some chronically-infected patients, it downregulates other immune reactions in order to protect the body. This state could act like a natural immunosuppressant and reduce the rejection of the organ."

In addition to the genes of the type I interferon system, a second factor was considered as a possible marker. This was discovered by the researchers in a previous study on liver recipients who did not have a HCV infection. Patients were very likely to be tolerant if they had a certain ratio of two different subgroups of immune cells in their blood. This ratio was also a reliable predictor of tolerance in the new study involving HCV patients.

INFORMATION: Dr. Tanja Bauer and Carolina Russo from the Immunmonitoring Platform at the Helmholtz Zentrum München were also involved in the study as cooperation partners. Felix Bohne was awarded a DFG (German Research Foundation) grant for his research work.

Original publication Felix Bohne, María-Carlota Londoño, Carlos Benítez, Rosa Miquel, Marc Martínez-Llordella, Carolina Russo, Cecilia Ortiz, Eliano Bonaccorsi-Riani, Christian Brander, Tanja Bauer, Ulrike Protzer, Elmar Jaeckel, Richard Taubert, Xavier Forns, Miquel Navasa, Marina Berenguer, Antoni Rimola, Juan-José Lozano, und Alberto Sánchez-Fueyo, HCV-induced immune responses influence the development of operational tolerance following liver transplantation in humans, Science Translational Medicine, 2014. DOI: 10.1126/scitranslmed.3008793

Contact Prof. Dr. Ulrike Protzer
Technische Universität München / Helmholtz Zentrum München
Institute of Virology
Phone: +49 89 4140 - 6821
protzer@tum.de
protzer@helmholtz-muenchen.de

ELSE PRESS RELEASES FROM THIS DATE:

Fruit flies help scientists uncover genes responsible for human communication

2014-06-26

COLUMBIA, Mo. – The evolution of language in humans continues to perplex scientists and linguists who study how humans learn to communicate. Considered by some as "operant learning," this multi-tiered trait involves many genes and modification of an individual's behavior by trial and error. Toddlers acquire communication skills by babbling until what they utter is rewarded; however, the genes involved in learning language skills are far from completely understood. Now, using a gene identified in fruit flies by a University of Missouri researcher, scientists involved in ...

Early surgical follow-up with primary care physicians can cut hospital readmissions

2014-06-26

(SALT LAKE CITY)—Patients who have post-operative complications following high-risk surgery have a significantly lower risk of being readmitted to the hospital within 30 days if they go see their primary care physician soon following discharge, a new study in JAMA Surgery shows. The study shows that better coordination of care between surgeons and primary care physicians is important to help reduce hospital readmissions within 30 days for those high-risk surgery patients who have post-operative complications or live with a chronic disease, according to Benjamin S. Brooke, ...

Managing specialized microbes to clean stubborn chemicals from the environment

2014-06-26

Chlorinated chemicals perform a host of societally useful functions, but they also have a dark side. Once their use life has ended, such agents often become environmental contaminants, sometimes resistant to bioremediation. In a series of new studies, Anca Delgado, a researcher at Arizona State University's Biodesign Institute, examines unique groups of microorganisms, capable of converting hazardous chlorinated chemicals like trichloroetheene (TCE) into ethene, a benign end product of microbial biodegradation. The research was conducted as part of her doctorate work ...

Peanuts don't panic parents as much as milk and eggs

2014-06-26

ARLINGTON HEIGHTS, Ill. (June 26, 2014) – It's tough being the parent of a child with food allergies. Constant vigilance is needed for everything your child eats, when a single food item containing a hidden ingredient can be fatal. Although worry is a factor for anyone caring for a child with food allergies, according to a study published in the July issue of Annals of Allergy, Asthma and Immunology, the scientific publication of the American College of Allergy, Asthma and Immunology (ACAAI), there is increased anxiety and strain for caregivers of children allergic to milk ...

To avoid interbreeding, monkeys have undergone evolution in facial appearance

2014-06-26

Old World monkeys have undergone a remarkable evolution in facial appearance as a way of avoiding interbreeding with closely related and geographically proximate species, researchers from New York University and the University of Exeter have found. Their research provides the best evidence to date for the role of visual cues as a barrier to breeding across species. "Evolution produces adaptations that help animals thrive in a particular environment, and over time these adaptations lead to the evolution of new species," explains James Higham, an assistant professor in ...

A breakthrough for organic reactions in water

2014-06-26

Green-chemistry researchers at McGill University have discovered a way to use water as a solvent in one of the reactions most widely used to synthesize chemical products and pharmaceuticals. The findings, published June 26 in Nature Communications, mark a potential milestone in efforts to develop organic reactions in water. Chao-Jun Li and Feng Zhou of McGill's Department of Chemistry report that they have discovered a catalytic system which for the first time allows direct metal-mediated reactions between aryl halides and carbonyl compounds in water. For the past ...

Research says TB infection may be underestimated among people taking corticosteroid pills

2014-06-26

TORONTO, June 26, 2014—Tuberculosis infection among people taking corticosteroid pills may be underestimated, new research suggests. Current guidelines for what constitutes a positive TB skin test among corticosteroid pill users may not be capturing all those who are infected, said Dr. Nicholas Vozoris, a respirologist in the Tuberculosis Program at St. Michael's Hospital. Previous research has shown that people who take corticosteroid pills, such as Prednisone, and have inhaled the TB bacteria, have an eight times higher risk of the bacteria becoming active than people ...

Men and women use mental health services differently

2014-06-26

TORONTO, June 26, 2014 – Women with chronic physical illnesses are more likely to use mental health services than men with similar illnesses; they also seek out mental health services six months earlier than those same men, according to new study from St. Michael's Hospital and the Institute for Clinical Evaluative Sciences (ICES). "Chronic physical illness can lead to depression," said Dr. Flora Matheson, a scientist in the hospital's Centre for Research on Inner City Health. "We want to better understand who will seek mental health services when diagnosed with a chronic ...

Continued use of low-dose aspirin may lower pancreatic cancer risk

2014-06-26

PHILADELPHIA — The longer a person took low-dose aspirin, the lower his or her risk for developing pancreatic cancer, according to a study published in Cancer Epidemiology, Biomarkers & Prevention, a journal of the American Association for Cancer Research. "We found that the use of low-dose aspirin was associated with cutting the risk of pancreatic cancer in half, with some evidence that the longer low-dose aspirin was used, the lower the risk," said Harvey A. Risch, MD, PhD, professor of epidemiology in the Department of Chronic Disease Epidemiology at the Yale School ...

Revisions needed for current IV feeding safeguards against bloodstream infections

2014-06-26

Current guidelines to help prevent bloodstream infections during intravenous feeding may need revisions to strengthen protections for patients, a new study finds. Researchers at the United Kingdom's University of Southampton found that current guidelines do not account for other independent factors that can affect the growth of potentially deadly microorganisms. Their study was published today in the OnlineFirst version of the Journal of Parenteral and Enteral Nutrition (JPEN), the research journal of the American Society for Parenteral and Enteral Nutrition (A.S.P.E.N.). ...

LAST 30 PRESS RELEASES:

The percentage of women who went without a Pap smear for cervical cancer screening increased following the COVID-19 pandemic, from 19% in 2019 to 26% in 2022

NEW STUDY: Across eight Amazon countries, forests on Indigenous lands reduce spread of 27 diseases – From respiratory ailments to illnesses spread by insects, animals