Treg therapy: the immune system learns to heal itself

Regulatory T-cells (Treg) are a special "police" group in our immune system. Unlike regular T-killers, which destroy everything suspicious, Treg cells perform the opposite function: they restrain excessive immune responses and prevent attacks on the body's own tissues. They are responsible for immune tolerance — that is, ensuring it doesn't fight against "its own."

When Treg function is disrupted, many problems arise. The immune system begins to aggressively attack its own cells and organs. This is how autoimmune diseases develop: multiple sclerosis, rheumatoid arthritis, systemic lupus erythematosus, type 1 diabetes, Crohn's disease, ulcerative colitis, and many others.

Scientists have now learned to isolate Treg cells from a patient, multiply them in large quantities in the lab, or even grow them from induced pluripotent stem cells (iPSC), and then reintroduce them into the body. Essentially, this is a "peacekeeping army" that we produce ourselves and send to restore order inside the body.

The first major clinical trials conducted in 2024–2026 have already shown promising results. In patients with severe autoimmune diseases, after Treg cell administration, there was a significant reduction in inflammatory markers, decreased symptoms, and in some cases, the ability to substantially reduce or even discontinue strong immunosuppressants, which have serious side effects.

Treg therapy looks particularly promising for organ transplantation. Instead of lifelong suppression of the entire immune system with powerful drugs (which greatly increases the risk of infections and cancer), doctors are trying to "retrain" the immune system to calmly accept a foreign organ. Some studies already show that patients after such therapy tolerate the transplant better and face rejection less often.

In addition to autoimmune diseases and transplantation, Treg therapy is being studied in the context of treating certain types of cancer, chronic inflammatory diseases, and even post-COVID syndrome with an autoimmune component.

Most studies are currently in phases I–II, but drugs are emerging that are approaching the registration stage. Many experts predict that in the next 5–8 years, Treg therapy could become a real clinical practice for a whole range of diseases.

The main advantage of this approach is that instead of crudely suppressing the immune system, we are trying to restore its natural balance. This is a fundamentally new level of treatment — not fighting symptoms, but correcting the very cause of the immune system's malfunction.

Source: Nature Reviews Immunology, Science Translational Medicine, key studies 2025–2026, Clinical trials on ClinicalTrials.gov (Treg cell therapy), Nobel Prize in Physiology or Medicine 2025 (works by Simon Sakaguchi and co-authors)