A study on the immune system of people with depression paves the way for diagnosing it with a test. It was published in the journal “Translational Psychiatry” in “Nature”.
Depression is one of the most common mental illnesses in the world. It is estimated that more than 300 million people suffer from itIn this context, one piece of evidence is growing stronger: the relationship between depression and immune system functioning. Behind this suspicion, a research team led by Federico Daray y Andrea ErrastiCONICET specialists at the Institute of Pharmacology of the UBA, Argentina, decided to analyze this relationship to see if it is possible identify patients with depression through analysis of the immune response in blood. The result surprised them: They managed to do so with an accuracy of more than 80%.
The clue was given by the modifications in specific cells of the immune system. “We also observed the existence of three subgroups of depressed patients with different immunological profiles, which opens the door for future follow-up studies to determine whether these subgroups are different types of inflammatory depression or different stages of the same disease,” explained Daray.
It has been known for some time that alterations in the quantity and activation of certain immune cells, together with elevated levels of inflammatory markers, are associated with the development and maintenance of depression. “We decided to undertake this study because of the growing evidence suggesting a relationship between the immune system and depression. When the study began, most work had focused on humoral markers of the immune system, particularly cytokines, but our group had a lot of experience in evaluating the innate and adaptive cellular immune system, that is, cells such as lymphocytes and monocytes. That is why we focused on these markers,” said Errasti.
The study was titled Deciphering the inflammatory signature of major depressive episode: insights from peripheral immunophenotyping in active and remission states, a case-control study and was published in the magazine Translational Psichiatry of Nature“We are seeking to identify a panel of biomarkers that can help distinguish subgroups of depressive patients and that can be the basis for future studies that attempt to predict the evolution of the disease or the response to treatment, which is an expanding and very attractive field, with a lot of translational potential,” added Errasti.
In this sense, in recent decades, research into mood therapy has not been a field with much innovation in the area of diagnosis and treatment. Currently, the scientists explain, In the world and in Argentina, a patient who consults for depression receives a clinical diagnosis and is treated the same as thirty years ago: with the so-called “Serotonin Reuptake Inhibitors” (SRIs) as first-line drugs. “However, we know that two-thirds of patients do not respond to these treatments or do so only partially. Therefore, there is still a considerable need to improve treatments. Modulating the immune system may be an attractive avenue, especially considering the repositioning of drugs that are already available for other indications,” Daray said.
His team’s research began in 2018 but the pandemic put it on hold. They had to change the way they worked to continue the study until they managed to recruit the necessary number of participants – 121 – in December 2022.
The study consisted of the clinical evaluation of patients with depression at different stages of the disease. To do this, they conducted a diagnostic interview and used different scales to measure the severity of the condition. In addition, they included healthy subjects of the same age and sex as the patients as comparators. A blood sample was obtained from all participants and immunological profile analyses were performed using flow cytometry and measurement of various inflammatory markers in plasma.
