What's Hot in 2026: Autoimmune Diseases

From civil war to ceasefire: harnessing regulatory T cells to reset the balance in autoimmune disease

2025 marked a historic moment in immunology with the Nobel Prize in Physiology & Medicine awarded to Fred Ramsdell, Mary E. Brunkow, and Shimon Sakaguchi for their groundbreaking work on peripheral tolerance, a mechanism that prevents our immune system from turning against us. This discovery laid the foundation for one of the most exciting frontiers in medicine: regulatory T cell (Treg) therapies.

Autoimmune disease occurs when the immune system wages war on its own tissues. During the 1990s, the concept of antigen-specific tolerogenic vaccines was introduced, leveraging suppressive dendritic cell populations that encourage Treg generation in the body. Step forward to 2009, and ‘peace’ was being restored by infusing patients with polyclonal Tregs that had been expanded outside the body before reinfusion, thereby increasing their relative numbers. These cells acted broadly, calming immune responses and showing promise in suppressing autoreactive cells. Fast forward to today, and innovation has significantly accelerated; genetically engineered chimeric antigen receptor (CAR)-Tregs and T cell receptor (TCR)-Tregs now offer precision targeting, dialing down harmful immune activity whilst preserving healthy immune responses.

Why does this matter? Compared to aggressive “immune reset” strategies where autoimmune conditions are treated by myeloablative treatment followed by autologous stem cell transplant to ‘reset’ the immune system, or via use of CAR-T cells which can wipe out all target-expressing B cells, whether they are autoreactive or not, Treg therapies promise a gentler, safer approach, leaving the immune compartment intact whilst still dampening autoreactive responses. This means patients are less at risk of opportunistic infection. 

Biotech leaders are driving this autoimmune revolution: Quell Therapeutics is tackling type 1 diabetes (T1D) and inflammatory bowel disease; Sonoma Biotherapeutics is targeting rheumatoid arthritis and Crohn’s disease and PolTREG is using a range of Treg-based approaches to treat T1D and neuroinflammation and neurodegeneration. Meanwhile, TRexBio uses artificial intelligence to decode Treg biology for next-generation therapies, aiming to treat at range of autoimmune and inflammatory conditions. With over 70 clinical studies involving regulatory T cells currently underway or about to start (clinicaltrials.gov), the momentum is undeniable.

So where next for Treg therapies? The autoimmune battlefield is changing…and the future looks bright. Combined with more precisely targeted CAR-T therapeutics, such as chimeric autoantibody receptor (CAAR-T) cells developed by companies such as Cabaletta Bio, which eliminate autoreactive B cells whilst leaving the remainder of the immune system intact, Treg-based therapies offer significant benefits as an alternative approach. With science, innovation, and collaboration, we’re not just treating disease; we’re rewriting the rules of immune tolerance. The era of precision peacekeeping has begun!

-- Louise Brackenbury, Science Director, Advanced Modalities