The 2025 Nobel Prize in Medicine opened a door autoimmunity needed.

Why doesn't the immune system — capable of destroying bacteria, viruses and cancer cells — attack us instead?

For decades, the answer was incomplete: it was known that the immune system "learns" not to attack self-tissue during development in the thymus — so-called central tolerance. But that mechanism isn't perfect, and cells capable of reacting against the body's own tissue routinely escape into circulation. Sakaguchi demonstrated in 1995 that a second line of defense exists: a specialized population of T lymphocytes — Tregs — whose job is to actively patrol and suppress any immune cell that threatens to attack self-tissue, outside the thymus.

Brunkow and Ramsdell completed the story in 2001 from another angle: they identified that mutations in the FOXP3 gene cause IPEX syndrome, a devastating, multisystem autoimmune disease in infants. FOXP3 turned out to be the master switch that converts an ordinary T lymphocyte into a Treg. Without it, there is no brake — and the body attacks itself almost immediately.

The 2025 Nobel Prize doesn't reward a treatment — it rewards confirmation that autoimmunity has, at its root, an identifiable and actionable biological brake.

If Tregs are the brake, can more brake be manufactured?

This is where regenerative medicine enters the conversation the Nobel Prize validates. Azevedo et al. (Stem Cells, 2020) showed that mesenchymal stem cells (MSCs) don't just generically "calm down" the immune system — they can convert conventional CD4 T lymphocytes into stable Tregs. This isn't an expansion of pre-existing Tregs: it's the manufacture of a new population, with an authentic Treg functional profile.

The mechanism is epigenetic: when cultured alongside MSCs, conventional T cells acquire a DNA methylation pattern that resembles a natural Treg more than their cell of origin — meaning the change is stable, not transient. Signaling occurs through two well-characterized pathways: TGF-β and the PD-1/PD-L1 axis, the same ones the immune system uses physiologically to induce peripheral tolerance.

The Nobel Prize confirmed which mechanism brakes autoimmunity. Azevedo 2020 showed stem cells can activate that same mechanism from the outside.

Inducing tolerance in an immune system on fire is harder than in a calm one

An active autoimmune disease isn't a silent immune system waiting for a signal to convert toward Treg — it's a system saturated with autoantibodies, circulating immune complexes and pro-inflammatory cytokines constantly pushing in the opposite direction: toward more activation, not more tolerance. Trying to induce Tregs in that context is swimming against the current.

Therapeutic Plasma Exchange (TPE) physically removes that circulating "noise" — autoantibodies, immune complexes, activated complement. ASFA guidelines (Connelly-Smith et al., J Clin Apheresis 2023) recognize numerous autoimmune diseases as Category I or II indications for TPE — solid, already-established evidence independent of any cell therapy. Lowering that systemic inflammatory load before attempting to induce immune tolerance doesn't replace the Treg mechanism — it gives it a less hostile biological ground to operate on.

First lower the inflammatory noise with TPE. Then, a quieter ground where the tolerance signal has a better chance of being heard.

This sequence is a plausible biological model, not an established clinical protocol or a promise of outcome. In Colombia, the therapeutic use of mesenchymal stem cells does not have formal INVIMA approval for general use and is evaluated case by case under individual medical judgment. TPE is an active clinical modality at Wellness Care, with autoimmune indications backed by ASFA guidelines.

Frequently asked questions about the 2025 Nobel Prize and autoimmunity

The questions we hear most often when explaining the relationship between the 2025 Nobel Prize in Medicine, regulatory T cells and autoimmune disease treatment.