A new and simple urine test that can detect a common cause of kidney transplant failure may help lead to better diagnosis and treatment of patients with polyomavirus nephropathy, which affects up to nine percent of kidney transplant recipients, according to a study appearing in the February issue of the Journal of the American Society of Nephrology.

While polyomaviruses are normally occurring viruses that harmlessly infect many adults, they can pose serious health problems for individuals who become immunocompromised. Such is the case for many kidney transplant recipients who must take immunosuppressive medications to safeguard against organ rejection. Some of these patients develop a damaging condition called polyomavirus nephropathy that can lead to chronic kidney failure and the need to re-initiate dialysis or undergo another transplant.

Because there are no effective therapies to treat polyomavirus nephropathy, it is important to diagnose the condition as early as possible, before it becomes serious. Therapy normally consists of lowering the dose of immunosuppressive drugs and hoping for natural viral clearance.

Unfortunately, there currently is no definitive way to accurately diagnose polyomavirus nephropathy. Physicians rely mostly on invasive and expensive kidney biopsies, which sometimes give false negative results.

But Volker Nickeleit of the University of North Carolina and his colleagues have discovered a new and noninvasive way to test for the condition.

The test measures "Haufen" -- a German term meaning stack or pile -- in the urine. Haufen are tightly clustered viral aggregates that form within the kidneys in patients with polyomavirus nephropathy and are excreted in the urine. Testing for Haufen is fast (three hours), inexpensive and easy to perform with current laboratory equipment.

Through their investigation, the researchers found Haufen in urine samples from all 21 patients with early or late stages of polyomavirus nephropathy, but not in any of the 139 individuals without the condition.

According to Nickeleit, the new test could help physicians identify and monitor patients with polyomavirus nephropathy and could guide them as they design new therapeutic strategies.

(Xinhua News Agency January 22, 2008)