Restoration of the immune system in adult HIV patients - thymus glands that produce new T cells

Scientists at Gladstone's Virology and Immunology Institute and experts at the University of California - San Francisco (UCSF) have found a therapy that can be used to stimulate the production of immune cells. need for life (T cells) in adults infected with HIV.

HIV disease destroys T cells leading to immune system damage and severe infection. The thymus gland that produces T cells gradually loses its function over time (this process is called ' dissipation '), becoming almost inactive during adulthood. Because the thymus gland does not function properly, it is difficult for HIV-infected adults to produce new T cells. Therefore, the therapy to stimulate the thymus gland to produce T cells can help HIV patients recover their immune systems.

Although people have long believed that the thymus gland cannot react in humans, new research has shown that the thymus gland can be stimulated to produce more T cells . This study has for the first time demonstrated pharmacological therapies that can be used to enhance the function of the thymus glands in the human body.

Dr. Laura Napolitano, the lead author of the study and an assistant investigator at the Gladstone Institute and assistant professor of medicine at UCSF, said: 'These results explain the findings that show the process of digestion. Thymus glands may be reversed in humans. Increasing T cell production can be very helpful for some diseases such as HIV or bone marrow transplantation. The finding also contributes a lot of new information about the production of T cells. It is also an important step to determine if immunotherapy may someday benefit patients who need it. many T cells or not '.

Exaggerated electron micrograph shows the presence of mature HIV virus in tissue samples studied.(Photo: CDC)

Based on promising studies on animals that growth hormone (GH) can enhance thymus function in older mice, investigators from Gladstone and UCSF have done a study. Random rescue and an interesting result: Growth hormone has increased thymus gland mass and T-cell growth in humans.

They studied 22 adult HIV patients for 2 years. Half of the participants were randomly selected to continue using conventional HIV therapies, while at the same time they used growth hormone in the first year (known as the GH group). Half of the remaining participants still use conventional HIV treatment without the use of growth hormone (limited group). In the second year of study, the limited group received growth hormone, and the GH group was discontinued. Immune system analysis is performed regularly for all participants. The thymus gland is examined by CT scans. The number and types of immune cells in the blood are determined by a progressive method called multi-parameter cell flow measurement.

All participants in the study applied effective HIV treatment for at least 1 year (the average duration of HIV therapy at about 3 years) and showed very good signs of viral suppression. Despite this, they still have a very low percentage of CD4 T-cells - a type of T-cell necessary for normal immune functions. At the beginning of the study, patients in both groups were not significantly different in terms of the average effective duration of HIV therapy, the incidence of HIV in the blood, age, rate of thymus or other. difference in the number of important immune parameters.

But the results with growth hormone are very encouraging. Napolitano's group found that the use of growth hormone increased the rate of thymus significantly and it also seemed to double the number of newly produced T-cells . In general, growth hormone users have a CD4 + T-cell count increase of about 30% (2.4 times higher than those who do not use growth hormone). The results continued to increase further for at least 3 months after stopping the growth of hormones and remained stable for at least 1 year after the absence of growth hormone.

Joseph M. McCune, a professor of medicine at UCSF, said: 'The study's findings are interesting. It also erased the previous notion that the thymus route could not work again. If these discoveries are made in larger studies, the information it brings will bring great joy to those who need new T cells, such as adult HIV patients or missing forms of disease. T cells' deficiency.

'But growth hormone should not be used as a treatment for immunological purposes for HIV disease or in any patient at this time. Unless this therapy is used in research. More research needs to be done if the stimulation of new T cell production is indeed beneficial to health, ' Napolitano and McCune warned.

Napolitano added: 'We have shown an increase in the number of T cells, but we also have to determine whether the restored thymus glands produce quality-guaranteed T cells to carry on. Whether immune is desired or not. This is only a relatively small study conducted on carefully selected adults to use HIV therapy. Our research may not be applicable to most people who are ill '.

While the sample of the study is quite small, Napolitano said a larger study conducted by the AIDS Treatment Group (ACTG) also obtained similar results through a preliminary analysis. They will announce the results soon. Napolitano is also a member of the ACTG group performing the above study. He said: 'The ACTG study will provide additional data for our understanding of the effect of growth hormone on the immune system.'

'Growth hormone is a protein that affects Tmos cells in the body. It may cause some side effects. We want to understand specific pathways that growth hormones affect the thymus gland so therapies are narrowed down towards the thymus gland '.

It should also be pointed out that in the commentary accompanying Clinical Investigation by Kiki Tesselaar and Frank Miedema (of the Utrecht Medical Center of the Netherlands) there is a warning that effective control of long-term immune treatment Growth hormone needs to be thoroughly tested before this method is used in extensive treatment.

Other participants in the study included Erin Filbert, Myra Ng, Julie Clor and Kai Li of the Gladstone Virus and Immunology Institute; Diane Schmidt, Michael Gotway, Niloufar Ameli, Lorrie Epling, Elizabeth Sinclair, Paul Baum, Marisela Lua Killian and Peter Bacchetti of the University of California - San Francisco. The study was conducted by a treatment research center at San Francisco General Hospital. The research was funded by the National Institutes of Health, Gladstone Institute, Serono Inc., and the AIDS Research Institute of the University of California San Francisco.