The immune system is undeniably the human body’s main line of defense against viruses, pathogens, and ailments of all physical varieties. Now, however, a potentially groundbreaking new set of research from Yale University theorizes that our immune systems may have an active role in staving off mental health problems as well.
More specifically, the research team at Yale has identified a set of immune cells that may be involved in preventing depression among healthy individuals. Those immune cells, referred to as gamma interferons, are a big part of jump-starting and controlling several immune system responses.
In fact, this discovery was made by comparing spinal fluid immune system cells of multiple sclerosis (MS) patients with those of healthy individuals. When the human body is faced with a disease like MS, an inflammatory autoimmune response occurs within the central nervous system. In short, this means that MS causes the immune system to attack the body’s own tissues, eventually causing communication problems between the brain and spinal cord.
Both gamma interferons, and the T cells they produce, are involved in the autoinflammatory immune response to MS.
To the research team’s surprise, they uncovered signs of similar T cells within the spinal fluids of healthy subjects with no signs of MS or any related disease. Importantly, though, observed T cells within healthy individuals’ spinal fluids could not replicate and inflict damage like the T cells seen in MS patients.
These unexpected observations have led the study’s authors to hypothesize that these particular immune cells are serving more than one purpose.
“We were surprised that normal spinal fluid would be so interesting,” explains senior study author David Hafler, the William S. and Lois Stiles Edgerly Professor of Neurology, and a professor of immunobiology, in a university release.
Backing up the research team’s theory is prior work that had found lab mice tend to become depressed whenever their gamma interferons are blocked. In addition, many human MS patients complain of more intense depressive feelings when they’re treated with a different type of interferon.
All of this is fairly complex and scientific, but in short, the research team has collected compelling evidence that the brain’s immune system sometimes mounts an “inflammatory immune system response” in the absence of any physical pathogens.
“These T cells serve another purpose and we speculate that they may help preserve our mental health,” professor Hafler concludes.
This is all still unconfirmed, and just a theory at this point. Moving forward, the study’s authors plan on conducting more research on this subject matter in hopes of better understanding the depth of the relationship between immune responses and depressive feelings.
Considering how far mental health discussions and acceptance in society have come over the past few years, it’s ironic to think that our bodies and immune systems may have been classifying depression as a legitimate illness for as long as humans have inhabited the planet.
The full study can be found here, published in Science Immunology.