Scientists from the Institute of Parasitology and Biomedicine López Neyra, which belongs to the Higher Council for Scientific Research (CSIC), in collaboration with experts from the Virgen de la Arrixaca Hospital in Murcia, have described the involvement of a type of immune system cells in the control of chronic Chagas disease.
Specifically, this group of lymphocyte cells recognizes the presence of the parasite that causes this serious disease and destroys this microorganism in infected cells. According to the conclusions of this study, published in the journal PLoS Neglected Tropical Diseases, these cells could be an important component against infection during the chronic phase of this disease.
“The findings shed light on the understanding of a cell population poorly described in this context,” says Manuel López, CSIC researcher.
In figures, Chagas disease is endemic to Latin America, where it affects more than eight million people and causes the death of approximately 20,000 each year, mainly due to heart damage, according to data from the World Health Organization (WHO).
In Spain, this disease affects around 70,000 people. The most common symptoms in the acute phase of this pathology caused by the unicellular parasite Trypanosoma cruzi are fever, headache, shortness of breath, swelling, and abdominal or chest pain, including neurological alterations.
“These changes are irreversible and in many cases they cause death. Chagas disease, which is transmitted through different routes such as blood transfusions or from mothers to children, is curable if treatment is given immediately after infection occurs. In cases of patients in the chronic phase, an adequate antiparasitic plan can slow or prevent the progression of it, “explains López.
In vivo tests
Experts have analyzed the response of a series of specialized cells of the immune system, specifically how they act and develop or deactivate according to the stage of development of the disease. It is a cell population called T CD4 + CD8 +, high , which percentage increases in the chronic phase of the disease after applying a treatment against Chagas that almost completely eliminates the parasite at the beginning of the acute stage .
To do this, they have performed in vivo tests with 38 patients suffering from an advanced state of this disease, 20 asymptomatic and 18 with heart damage who never received any treatment for their disease. After administering oral medication (benznidazole) for over 60 days was given over 60 days, they were followed up for 48 months.
The follow up consisted of extracting blood and analyzing the lymphocytes and other clinical parameters in order to evaluate their association with the progress or stagnation of this pathology.
“Treatment with this drug has shown that in any of the cases —in both in chronic patients without apparent symptoms or in those suffering from heart disease as a result of this disease— is effective and increases the frequency and functional capacity of the aforementioned lymphocytic cells,” says this researcher.
Thus, these cells are capable of killing those cells already infected, in patients with a chronic condition. In those with ailments in the heart, despite the fact that the cardiac damage persists, the aforementioned immune activation occurs, making it possible to control the infection. In patients without symptoms, the cells enhance their cytotoxic capacity, favoring their fight against the parasite.
This study, funded by the Ministry of Science, Innovation and Universities, the Carlos III Institute and FEDER Funds, continues to deepen the search for possible cellular biomarkers that can be used as tools to assess therapeutic efficacy in the chronic phase of Chagas disease.