Leishmaniasis is a tropical disease that is affecting an increasing number of people around the world. Every year, there are between 700,000 and 1 million new cases reported. This disease is caused by a parasite called Leishmania, which is transmitted to humans through the bite of a sand fly. There are three clinical forms of leishmaniasis, with the visceral form being the most severe. If left untreated, visceral leishmaniasis, also known as black fever, is almost always deadly.
A team led by Simona Stäger has made a discovery that could potentially lead to a treatment for the most severe form of leishmaniasis.Leishmaniasis is a disease that is becoming more widespread globally. Each year, there are between 700,000 and 1 million new cases reported. It is caused by a parasite called Leishmania, which is transmitted to humans through the bite of a sand fly. There are three clinical forms of leishmaniasis, with the visceral form being the most severe. If not treated, visceral leishmaniasis, also known as black fever, is almost always fatal. Most cases are found in Bangladesh, Brazil, Ethiopia, India, Nepal, and Sudan.
Professor Simona Stäger and her team at the Institut national de la recherche scientifique (INRS) are working in collaboration to address this issue.Researchers from INRS and McGill University have uncovered an unexpected immune mechanism associated with chronic visceral leishmaniasis. This finding could pave the way for a new therapeutic approach to treating the disease. The results of their study have been published in the journal Cell Reports.
In many infections, CD4 T cells are crucial in defending the body. However, in chronic infections like leishmaniasis, maintaining a sufficient number of functional CD4 cells becomes challenging, as the immune system is continuously activated to fight the pathogen.
ected person.
New immunity soldiers to the rescue
Yet, the research conducted by Professor Stäger in her laboratory at INRS’s Armand-Frappier Santé Biotechnologie Research Centre indicates that these cells may have multiple abilities to maintain their vitality.
When studying these new cells, the scientists observed that they multiply during the chronic phase of the disease. They also found that, similar to progenitor cells, they can either renew themselves or transform into other effector cells that eliminate the parasite, or regulatory cells that suppress the host’s immune response.
Response.
According to Professor Simona Stäger, CD4 T cells typically transform into effector cells from “naive” CD4 T cells. However, during chronic infections, the constant demand for effector cells can overwork naive CD4 T cells, leading to exhaustion.
“We believe that during the chronic phase of visceral leishmaniasis, the newly identified population is responsible for producing effector and regulatory cells. This allows the host to prevent exhaustion of its existing pool of naive CD4 T cells for a specific antigen,” explains Ph.D. student and first author.Research conducted by Sharada Swaminathan has led to the discovery of a new type of lymphocyte that could potentially enhance the immune system. This new discovery has the potential to replace the overworked naive CD4 T cells and boost the body’s ability to fight off infections, such as the Leishmania parasite. Simona Stäger, Vice-Director of the Infectiopole and member of Pasteur Network, expressed optimism about the potential of directing this new lymphocyte population to become a protective effector cell. This breakthrough has the potential to not only combat the Leishmania parasite but also potentially lead to cures for other infections. Additionally, the study notes that similar cells to this new CD4 T lymphocyte population have been observed in mice during infection.The population of cells identified by Professor Stäger’s team has been found in mice infected with lymphocytic choriomeningitis virus and in mice with the H. polygyrus intestinal worm. This suggests that these cells may also be present in other chronic infections or inflammatory environments.
This discovery opens up the possibility of using these cells for therapeutic purposes beyond visceral leishmaniasis, potentially also for treating other chronic infections,” says Professor Stäger.
