The University Medical Center (UMC) Utrecht is home to the European knowledge center for HIV and AIDS. At both the Department of Immunology and the Department of Medical Microbiology (Virology), researchers are studying how the immune system works and the virus’s resistance (insensitivity) to drugs.
How does HIV cause damage to the entire immune system? And why is the immune system unable to protect itself effectively against the virus? Immunologist Miedema has been looking for the answers to these questions since 1985.
Disappearing T helper cells
As soon as HIV enters the human body, it goes looking for white blood cells that play an important part in the body’s defense system: the T helper cells. The virus attacks and destroys these cells. Researchers used to believe that the virus destroyed a large number of T helper cells every day. The defense system would then start to work overtime to continuously manufacture new ones. But at a certain point, the body’s supply of T helper cells is used up and the number of cells drops rapidly. The patient becomes susceptible to infections and develops AIDS as a result.
Hyperactive defense system
Miedema discovered that this conclusion was incorrect. “Each day only a relatively small number of cells are killed by the virus. Although HIV actually infects only a very few cells, it does however activate a large number of others. This causes a general immune response, and as a result the entire immune system works somewhat harder than usual. Because there is a limit to the production of new cells, the system can’t handle this small amount of additional daily activity and cell death. The number of T helper cells slowly decreases and there is a continuous inflammation response. The defense system then starts to malfunction and the patient develops a variety of life-threatening infections. In our study, we want to learn more about the production and death of these T helper cells. We are also studying why virtually none of the patients are able to keep the HIV infection under control.”
Viruses become resistant
Over the past twenty years, researchers have successfully developed medicines for treating HIV and AIDS. Antiviral drugs are freely available, and these work well as long as patients take them as directed. If they do not do so, the viruses no longer respond to the medicines: they become resistant.
Immediately usable
Together with their doctor, a patient in whom the virus has become resistant discusses a new therapy, one tailor-made to their situation. This is based on research. At the Department of Virology at UMC Utrecht, clinical virologist Boucher is studying how HIV viruses become resistant and how harmful these resistant viruses are to humans. “What we learn from the virus today we can use tomorrow in the treatment of patients. Because UMC Utrecht is the European knowledge center, all HIV patients benefit from what we discover here. And this motivates me.”