Featured Research

from universities, journals, and other organizations

Protein-based urine test predicts kidney transplant outcomes

Date:
August 22, 2013
Source:
NIH/National Institute of Allergy and Infectious Diseases
Summary:
Levels of a protein in the urine of kidney transplant recipients can distinguish those at low risk of developing kidney injury from those at high risk, a study suggests. The results also suggest that low levels of this protein can rule out rejection as a cause of kidney injury.

Levels of a protein in the urine of kidney transplant recipients can distinguish those at low risk of developing kidney injury from those at high risk, a study suggests. The results also suggest that low levels of this protein, called CXCL9, can rule out rejection as a cause of kidney injury. The study appears online Aug. 22 in the American Journal of Transplantation. The work was funded by the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health.

Related Articles


To prevent rejection, kidney transplant recipients typically take immunosuppressive drugs every day. However, these drugs can cause kidney damage and lead to other serious side effects such as cancer, infection and infertility. Even with immunosuppressive therapy, 10 to 15 percent of kidney recipients experience rejection during the first year after transplantation.

Currently, the only definitive way to distinguish rejection from other causes of kidney injury is by performing a biopsy, in which doctors remove a small piece of kidney tissue to look for rejection-associated damage. Although this procedure is generally considered safe, it carries some minor risks for the patient and does not always provide an accurate impression of the overall state of the kidney.

"A noninvasive urine test to accurately monitor the risk of kidney rejection could dramatically reduce the need for biopsies and possibly enable doctors to safely reduce immunosuppressive therapy in some patients," said NIAID Director Anthony S. Fauci, M.D. "The results of this study support the further development of noninvasive tests for the detection and management of transplant rejection."

In this multicenter Clinical Trials in Organ Transplantation study, doctors periodically collected urine samples from 280 adult and child kidney transplant recipients for two years after transplantation. Investigators led by Peter Heeger, M.D., of the Icahn School of Medicine at Mount Sinai in New York City, and Donald Hricik, M.D., of Case Western Reserve University in Cleveland, measured the urinary levels of molecules that had previously been associated with rejection. These included two proteins and nine messenger RNAs (mRNAs) -- intermediary molecules in the construction of proteins from genes. They identified CXCL9 protein and CXCL9 mRNA as potential biomarkers -- molecules that indicate the effect or progress of a disease -- for the diagnosis of rejection.

After further testing, the researchers found that CXCL9 protein was better at ruling out rejection than any of the mRNAs tested. Low levels of the protein biomarker also could identify patients likely to have stable long-term kidney function. Transplant recipients with low urinary CXCL9 protein six months after transplantation were unlikely to experience rejection or loss of kidney function over the next 18 months. In addition, detection of the protein in the urine of transplant recipients was more straightforward than measuring mRNA levels. While proteins can be measured directly in urine, mRNAs must first be extracted from urine samples. The researchers obtained sufficient mRNA from just 76 percent of samples, highlighting the technical challenges of extraction.

"The relative ease of measuring urinary proteins suggests that developing a protein-based urine test for use in clinical practice would be less complicated than an mRNA test," said Daniel Rotrosen, M.D., director of NIAID's Division of Allergy, Immunology and Transplantation. "There is strong precedent for the development and use of tests that measure urinary proteins, such as home pregnancy tests."

CXCL9 protein levels also may be useful for predicting and monitoring transplant rejection. The investigators noted that urinary CXCL9 levels began to increase up to 30 days before clinical signs of kidney injury, which could allow doctors to intervene early to potentially avoid rejection-associated kidney damage. The protein levels began to drop after treatment for rejection, suggesting that the urine test could be used to monitor treatment progress.

"Development of noninvasive tests to detect immune activation before kidney damage occurs would help guide the care of kidney transplant recipients," said NIAID Transplantation Branch Chief Nancy Bridges, M.D., a co-author of the paper. "Clinical application of the findings from this study could help avoid unnecessary biopsies and excess immunosuppression."


Story Source:

The above story is based on materials provided by NIH/National Institute of Allergy and Infectious Diseases. Note: Materials may be edited for content and length.


Journal Reference:

  1. D. E. Hricik, P. Nickerson, R. N. Formica, E. D. Poggio, D. Rush, K. A. Newell, J. Goebel, I. W. Gibson, R. L. Fairchild, M. Riggs, K. Spain, D. Ikle, N. D. Bridges, P. S. Heeger. Multicenter Validation of Urinary CXCL9 as a Risk-Stratifying Biomarker for Kidney Transplant Injury. American Journal of Transplantation, 2013; DOI: 10.1111/ajt.12426

Cite This Page:

NIH/National Institute of Allergy and Infectious Diseases. "Protein-based urine test predicts kidney transplant outcomes." ScienceDaily. ScienceDaily, 22 August 2013. <www.sciencedaily.com/releases/2013/08/130822134000.htm>.
NIH/National Institute of Allergy and Infectious Diseases. (2013, August 22). Protein-based urine test predicts kidney transplant outcomes. ScienceDaily. Retrieved December 22, 2014 from www.sciencedaily.com/releases/2013/08/130822134000.htm
NIH/National Institute of Allergy and Infectious Diseases. "Protein-based urine test predicts kidney transplant outcomes." ScienceDaily. www.sciencedaily.com/releases/2013/08/130822134000.htm (accessed December 22, 2014).

Share This


More From ScienceDaily



More Health & Medicine News

Monday, December 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Christmas Kissing Good for Health

Christmas Kissing Good for Health

Reuters - Innovations Video Online (Dec. 22, 2014) Scientists in Amsterdam say couples transfer tens of millions of microbes when they kiss, encouraging healthy exposure to bacteria. Suzannah Butcher reports. Video provided by Reuters
Powered by NewsLook.com
Brain-Dwelling Tapeworm Reveals Genetic Secrets

Brain-Dwelling Tapeworm Reveals Genetic Secrets

Reuters - Innovations Video Online (Dec. 22, 2014) Cambridge scientists have unravelled the genetic code of a rare tapeworm that lived inside a patient's brain for at least four year. Researchers hope it will present new opportunities to diagnose and treat this invasive parasite. Matthew Stock reports. Video provided by Reuters
Powered by NewsLook.com
Americans Drink More in the Winter

Americans Drink More in the Winter

Buzz60 (Dec. 22, 2014) The BACtrack breathalyzer app analyzed Americans' blood alcohol content and found out a whole lot of interesting things about their drinking habits. Mara Montalbano (@maramontalbano) has more. Video provided by Buzz60
Powered by NewsLook.com
Touch-Free Smart Phone Empowers Mobility-Impaired

Touch-Free Smart Phone Empowers Mobility-Impaired

Reuters - Innovations Video Online (Dec. 21, 2014) A touch-free phone developed in Israel enables the mobility-impaired to operate smart phones with just a movement of the head. Suzannah Butcher reports. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins