Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Gene pattern may identify kidney transplant recipients who don't need life-long anti-rejection drugs

25.05.2010
Researchers have identified a distinct pattern of gene expression in the largest reported group of kidney transplant recipients who have not rejected the transplant kidneys even though they stopped taking anti-rejection drugs.

This finding may help identify other transplant recipients who could safely reduce or end use of immunosuppressive therapy. In 2008, more than 80,000 people in the United States were living with a kidney transplant.

The findings come from the Immune Tolerance Network (ITN), an international research consortium supported by the National Institute of Allergy and Infectious Diseases (NIAID) and the National Institute of Diabetes and Digestive and Kidney Diseases, of the National Institutes of Health, and the Juvenile Diabetes Research Foundation International.

The research team included three lead investigators, Kenneth Newell, M.D., Ph.D., of Emory University in Atlanta; Laurence Turka, M.D., of Beth Israel Deaconess Medical Center and Harvard Medical School in Boston; and Vicki Seyfert-Margolis, Ph.D., the former Chief Scientific Officer of ITN and currently at the Food and Drug Administration. Their report appears online in the Journal of Clinical Investigation.

"The immunosuppressive therapy regimens that organ transplant recipients must endure have toxic side effects and increase the recipients' vulnerability to infections and cancer," says NIAID Director Anthony S. Fauci, M.D. "This study holds promise for identifying kidney transplant recipients who might be able to minimize or withdraw from their use of anti-rejection drugs. However, large, prospective studies will be necessary to determine if the same biomarkers identified in the current study are reliable predictors of immune tolerance."

Following a kidney transplant, recipients must be placed on immunosuppressive therapy or their immune systems will reject the transplanted organ. However, these drugs suppress the entire immune system, reducing an individual's ability to fight infections, and sometimes leading to diseases related to a weakened immune system, such as cancer. The drugs also have other severe side effects such as diabetes, hypertension and heart disease, as well as swelling, weight gain, and excessive hair growth and acne that many people find intolerable.

In rare cases, a physician may stop a transplant recipient's immunosuppressive drugs because of a serious medical problem such as cancer or life-threatening infection. In other cases, transplant recipients decide to reduce or stop immunosuppressive therapy against their physicians' advice, even though by doing so, they risk losing their transplanted organ. However, in a very small percentage of such cases, rejection does not occur after the drugs are stopped.

This study included 25 kidney transplant recipients who had ceased taking their immunosuppressive drugs of their own accord and yet had retained normal kidney function for more than one year. The researchers compared this group with two other groups: recipients who were still taking their immunosuppressive medication and had healthy kidneys, and healthy, non-transplant controls.

The team examined blood samples taken from participants in each of the three groups. They analyzed the gene expression of the cells in whole blood and observed that the transplant recipients who were not taking medication had a distinct pattern of genes expressed by B cells, a type of white blood cell. This pattern differed from those seen in participants who were still on immunosuppressive therapy and in non-transplant healthy control subjects. Further study identified a pattern of expression of three B cell genes that was far more common in patients who had stopped taking their medications yet maintained good graft function.

White blood cells include T and B cells. Recent studies of immune tolerance have focused on the role of a subset of T cells, called regulatory T cells (Tregs). Work in animal models indicates that B cells also may help promote immune tolerance.

"We expected to find a difference between the tolerant and immunosuppression groups in the genes associated with Tregs," says Dr. Newell. "However, we were surprised that our data showed that B cell genes may play an important role in maintaining and possibly inducing tolerance to transplanted organs."

According to Dr. Turka, identifying potential biomarkers of immune tolerance is the first step in identifying transplant recipients whose immunosuppression therapy could be reduced. "If we could develop a reliable tolerance signature—a pattern of gene expression that indicates that someone will not reject a transplant—then we could find patients who would make good candidates for supervised drug withdrawal," he said.

The study team stresses that transplant patients should never consider reducing or changing their medication regimen unless under the direct supervision of their physician. According to Drs. Newell and Turka, doing so would "almost certainly result in the rejection of the kidney, leaving the patient in need of another transplant."

Follow-up studies of this gene pattern are being planned. Similar findings already have been provided by a European group, led by King's College in London, that conducted a comparable study in kidney transplant patients. Their results appear in the same issue of the Journal of Clinical Investigation.

"The goal of ITN is to understand how immune tolerance can be induced or achieved in a variety of settings, including allergy, autoimmune disease and transplantation," says Daniel Rotrosen, M.D., director of the Division of Allergy, Immunology and Transplantation at NIAID. "Potentially, a biomarker for tolerance in kidney transplant recipients may predict tolerance in individuals following transplantation of other organs or with other immune-mediated diseases. Having a cooperative program like ITN allows investigators to explore this possibility and apply the findings of one study across different fields of clinical research."

NIAID conducts and supports research—at NIH, throughout the United States, and worldwide—to study the causes of infectious and immune-mediated diseases, and to develop better means of preventing, diagnosing and treating these illnesses. News releases, fact sheets and other NIAID-related materials are available on the NIAID Web site at www.niaid.nih.gov.

NIDDK, part of NIH, conducts and supports basic and clinical research and research training on some of the most common, severe and disabling conditions affecting Americans. The Institute's research interests include: diabetes and other endocrine and metabolic diseases; digestive diseases, nutrition, and obesity; and kidney, urologic and hematologic diseases. For more information, visit www.niddk.nih.gov.

The National Institutes of Health (NIH)—The Nation's Medical Research Agency—includes 27 Institutes and Centers and is a component of the U. S. Department of Health and Human Services. It is the primary federal agency for conducting and supporting basic, clinical and translational medical research, and it investigates the causes, treatments and cures for both common and rare diseases. For more information about NIH and its programs, visit www.nih.gov.

Reference: KA Newell et al. Characteristics of tolerant renal transplant recipients: evidence for a unique B cell signature associated with tolerance. Journal of Clinical Investigation. DOI: 10.1172/JCI39933 (2010)

Julie Wu | EurekAlert!
Further information:
http://www.niaid.nih.gov

More articles from Health and Medicine:

nachricht NTU scientists build new ultrasound device using 3-D printing technology
07.12.2016 | Nanyang Technological University

nachricht How to turn white fat brown
07.12.2016 | University of Pennsylvania School of Medicine

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

NTU scientists build new ultrasound device using 3-D printing technology

07.12.2016 | Health and Medicine

The balancing act: An enzyme that links endocytosis to membrane recycling

07.12.2016 | Life Sciences

How to turn white fat brown

07.12.2016 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>