October 9, 2007
DURHAM, N.C. -- The Human Vaccine Institute at Duke University Medical Center has been awarded a $7.6 million contract from the National Institute of Allergy and Infectious Diseases (NIAID) to expand its efforts to standardize and improve the quality of a crucial blood test used in the treatment of millions of HIV patients worldwide.
The Duke program centers on the testing of cells called CD4 cells, which are the immune system’s main defense against HIV. HIV weakens and overwhelms the immune system by attacking and killing these CD4 cells. Doctors test the blood of HIV patients to measure the number of CD4 cells present, and the results reveal how much damage the virus has done to the immune system. For patients taking antiretroviral drugs, or those who have received experimental HIV vaccines, CD4 cell counts also reveal whether those interventions are effective.
There are different methods of performing tests that measure CD4 levels, and those differences mean that test results can vary significantly from one lab to the next – especially when labs are located in different countries and use different equipment. The variation in test results can make it difficult for clinicians to make treatment decisions, and for researchers to determine whether new treatments are effective.
"When HIV patients in Tanzania have lower CD4 levels than comparable patients in North Carolina, what does that mean?" said Thomas Denny, the lead investigator for the project. "Does it mean that the patients in Tanzania are responding less effectively to their drugs? Does it mean that a new, resistant strain of the virus is emerging there? Or does it mean that the CD4 testing there is being done differently and yielding different results?
"This grant is going to help us implement uniform testing around the world, so researchers can get an accurate snapshot of what’s happening across the population," Denny continued. "It’s going to enable doctors in the field to make good decisions in the treatment of individual patients, and it’s going to make it easier for public health authorities to establish treatment guidelines as new therapies emerge."
The testing standards developed through Duke’s program will be implemented in every HIV clinical trial being funded by NIAID. Research programs administered by the Centers for Disease Control and Prevention and many other organizations will also have access to the new standards as well, and the grant provides funding for Duke experts to help provide international training for sites funded by the U.S.
"Tom Denny's Immunology Quality Assurance program funded by the NIH is a key program and asset for all translational work at Duke," said Bart Haynes, M.D, Director, Duke Human Vaccine Institute. "His program ensures that the Center for HIV/AIDS Vaccine Immunology as well as other laboratory programs funded by the NIH are up to good laboratory practice standards and collect data on human immune function appropriately during the course of clinical trials."
The Duke program is currently working with 82 labs in the U.S. and 78 labs across 28 other countries in Africa, Latin America, South America and the Caribbean, said Denny.
In the next phase of the project, Denny’s team will help labs in small, regional clinics to implement new testing standards and put in place quality control programs to help technicians monitor the accuracy of their lab’s testing.
"In the early phase of the project, we focused on larger hospitals and treatment centers," said Denny. "Next, we’re going to bring this same standardization and quality improvement program to labs in very remote locations. One of our key challenges has been to develop tests that are very sensitive and yield accurate and uniform results, yet are simple enough to be done in clinics that don’t have the sophisticated equipment you’d find in a larger hospital. These smaller clinics in countries like Tanzania and South Africa are where the majority of the world’s HIV patients are being tested and treated."
The movement toward uniform testing standards is also helping to reduce the cost of testing, which is helping countries hard hit by the HIV pandemic to test more people. According to Denny, it cost about $50 to test the CD4 level of a patient a decade ago, and that cost has come down to below $20 today. He estimates that within five years, the cost of a single test will fall below $10.
Contact: Richard Merritt