February 26, 2008
New research from scientists at the Gladstone Institute of Virology and Immunology and the University of California-San Francisco is the first to show that treatment with a growth hormone can reactivate the thymus and immune system in patients with long-term HIV infection.
HIV infection wipes out immune cells and causes the collapse of the entire immune system, leaving patients vulnerable to even minor infections. In the developing world, a major cause of death among HIV patients is tuberculosis and pneumonia as their immune systems are too weak to fight off the infections.
In the study, the scientists enrolled 22 HIV patients who had received standard HIV treatment for an average of three years. The patients were divided into two groups, with one receiving regular injections of growth hormone and the other continuing HIV treatment as before. After one year, the groups were switched.
The scientists used blood samples and medical scans to assess how well the patients responded throughout the treatment. When patients were given the growth hormone, their thymus increased in size and produced two times as many fresh T cells, the team found. The cellular boost persisted for at least one year after the injections were halted.
According to study leader Laura Napolitano, the findings are proof of principle that growth hormone could reverse HIVs damage, an important step to determine whether immune therapies might someday benefit patients who need more T cells. However, the scientists said it is too early to consider growth hormone as a general treatment. Growth hormone is known to have side effects, including an increased risk of diabetes, bone pain, swelling of the arms and legs, abnormal bone growth, and carpal tunnel syndrome.
The study, Growth Hormone Enhances Thymic Function in HIV-1-Infected Adults, was published in the Journal of Clinical Investigation (2008;doi:10.1172/JCI32830).