Scientists say discovery of 'new rules for the immune system' could improve treatment of inflammatory diseases

This overturns the previous idea that regulatory T cells exist as specialized populations restricted to specific sites in the body. This discovery has implications for the treatment of a variety of diseases, because almost every illness or injury stimulates the body's immune system.

Current anti-inflammatory drugs treat the whole body, not just the area that needs treatment. The researchers say this discovery means they may be able to suppress the body's immune response and repair damage in specific areas without affecting other parts of the body. This means higher doses and more targeted drugs could be used to treat the disease, potentially resulting in faster results.

“We've discovered new laws for the immune system – this 'unified army of healers' can do everything from repairing damaged muscles to making fat cells respond to insulin to regenerating hair follicles. It's fantastic to think that this could be used for such a wide range of diseases – potentially almost every disease,” said lead author Professor Adrian Liston from the Department of Pathology at the University of Cambridge.

To reach their findings, the researchers analyzed regulatory T cells in 48 different tissues in mice, and found that the cells are not specialized or static, but rather migrate around the body to where they are needed. Their findings are published today in the journal Neurology. Immunity.

“It's hard to think of a disease, injury or infection that doesn't involve some sort of immune response, and our discovery really changes the way we regulate this response,” Liston said.

“Now that we know that these regulatory T cells are present throughout the body, we could, in principle, initiate immunosuppressive and tissue regeneration treatments that are targeted to single organs. This would be a major improvement over current treatments, which involve hitting the body with a sledgehammer,” he added.

Using drugs they have designed, the researchers have demonstrated in mice that they can attract, increase, and activate regulatory T cells to a specific part of the body, shutting down an immune response and promoting healing in just one organ or tissue.

“By increasing the number of regulatory T cells at target sites in the body, the body becomes better able to repair itself and manage the immune response,” Liston said.

He adds: “There are many diseases, including autoimmune diseases like multiple sclerosis and many infectious diseases, in which you want to turn off the immune response and turn on the repair response.”

Most symptoms of infectious diseases such as COVID come not from the virus itself, but from the body's immune system attacking the virus. Once the virus has peaked, regulatory T cells are supposed to shut down the body's immune response, but in some people this process is not very efficient, which can lead to ongoing problems. This new discovery means that it may be possible to shut down a patient's immune response in their lungs with drugs, while the immune system in the rest of the body continues to function normally.

As another example, people who receive organ transplants must take immunosuppressants for the rest of their lives to prevent organ rejection because their body mounts a strong immune response to the transplanted organ, but this makes them highly susceptible to infections. This new discovery can help design new drugs that only suppress the body's immune response to the transplanted organ, allowing the rest of the body to function normally and allowing patients to lead normal lives.

Most white blood cells attack infections in the body by triggering an immune response. In contrast, regulatory T cells act like a “unified healing army” whose purpose is to shut down immune responses after they have done their job and to repair tissue damage caused by them.

The researchers are currently raising funds to set up a spin-out company, with the aim of conducting clinical trials to test their findings in humans within the next few years.