The study was developed by the FM-USP (Faculty of Medicine of the University of São Paulo) and published in the journal Immunity and aging puts chronic obstructive pulmonary disease (COPD) among those that lead to premature aging of the immune system.
The finding may be a way to explain why people with the disease have a lower response to vaccines and are more sensitive to infection processes, for example.
The researchers concluded that COPD patients have a number of changes associated with cell aging, a process called immunosensitivity that affects CD4 + and CD8 + T lymphocytes and impairs the immune response.
For the study, 92 individuals were recruited, divided into four groups: COPD patients, smokers without signs of lung disease, healthy elderly, and young adults. The researchers analyzed seven markers associated with late differentiation, aging, and cell depletion in each of these groups.
They concluded that patients with chronic obstructive pulmonary disease have cells that express any aging or depleted phenotypes, consistent with the features of premature aging of the immune system.
COPD is a chronic inflammatory disease characterized by tobacco smoke and air pollution. The World Health Organization estimates that the disease affects about 64 million people, and in Brazil about 6 million, 60% of whom are smokers or ex-smokers.
“As the aging population grows, understanding the mechanisms involved in immunosensitivity is important in many ways. Understanding how to treat the body of these people, who are more susceptible to cancer, infections and less sensitive to vaccines, can pave the way for a better immune system. This work will help understand what happens and where. it is possible to try to act, ”explains Professor Gil Benard of the FM-USP Laboratory of Dermatology and Immune Deficiency and director of the supported study, FAPESP.
The first author of the study, a Ph.D., Juliana Ruiz Fernandes explains that comparing data from people of the same age in COPD patients had accelerated T-cell aging. “The lymphocyte phenotype of these individuals appears to be older compared to those without a chronic inflammatory process,” Fernandes told Agência FAPESP.
In the smoking group, the results suggest that moderate to heavy chronic smoking did not accelerate immunosensitivity compared to healthy elderly adults. “COPD ended up bothering patients more than age, with a strong impact on the immune system,” says PhD student Thalyta Nery Carvalho Pinto, who is also the author of the article.
In her dissertation in 2016, Fernandes had demonstrated the effect of physical training on the immune response in COPD patients and found that a rehabilitation program was able to slow some of the parameters of cell aging and improve the immune response of lymphocytes.
At that time, the results suggested that patients had a higher proportion of cells with an exhaustion profile and poorer functioning. “We are now trying to understand the cell types associated with COPD and the elderly,” the researcher says.
Immunosensitivity is characterized by a decrease in the total number of young T cells (which scientists call naive) and an increase in memory lymphocytes, which have a three-stage dynamics during human life.
The first is characterized by a number of young cells that, over time, become memory cells in response to stimulation with specific antigens. The second stage (called memory homeostasis) is characterized by the circulation of memory T cells that reach the plateau and persist throughout adulthood.
In the third stage, after a long period of stability, the frequency and function of memory T cells change, increasing the susceptibility to infections caused by the immune disorder as part of physiological impairment.
In the work, the researchers found a “disorder” in this cycle of the immune system in patients with COPD. Not only did they have a decreased number of naive cells for immune responses, but also, paradoxically, an increased proportion of these cells, which had differentiation, aging, or depletion characteristics compared to healthy elderly people and smokers.
“We also saw that the immunosensitivity and changes in COPD individuals are more pronounced in CD8 + T lymphocytes, which act as a kind of‘ soldier ’responsible for eliciting an immune response in the human body,” Benard says.
Now, a team of researchers is examining the response of type B lymphocytes in COPD patients with a sample of different individuals. It also aims to assess how these people respond to the covid-19 vaccine.