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A Medical Explainer No. 001 — Autoimmune Disease

The body
turning on
itself.  a story of 1 in 300

Type 1 diabetes is not caused by sugar, nor lifestyle, nor anything a child could have done differently. It is the immune system — our body's defender — quietly mistaking the pancreas for an invader, and spending months silently destroying the cells that keep us alive. This is what we know, what we don't, and who is racing to fix it.

Also known as
Juvenile · T1D · IDDM
First described
~1552 BCE
First survivable
January 1922
Known cure
None — yet

§ 01 — MechanismThe Biology

A hormone stops arriving.
Everything downstream breaks.

Every cell in your body runs on glucose. Insulin is the key that unlocks the door. In Type 1 diabetes, the factory that makes the key — a cluster of beta cells tucked inside the pancreas — is demolished by the immune system. The doors stay locked. Glucose piles up in the blood. Cells, starved, begin to cannibalize fat for fuel, releasing acidic byproducts that, untreated, kill within weeks.

FIG. 1 — THE AUTOIMMUNE ATTACK Islet of Langerhans ~1–2 MILLION PER PANCREAS T-CELL (the attacker) BETA CELL (makes insulin) DESTROYED CELL (factory down) By the time symptoms appear, ~80% of beta cells are already gone.
FOUR THINGS HAPPENING AT ONCE
i.
The trigger. In a genetically susceptible person, some event — likely viral, possibly environmental — flips the immune system's recognition of beta cells from "self" to "foreign." The exact trigger is still unknown.
ii.
The silent war. T-cells infiltrate the pancreas and begin destroying beta cells. This phase can last months to years with no outward symptoms.
iii.
Collapse. Once roughly four-fifths of insulin production is gone, blood sugar rises fast. Thirst, weight loss, exhaustion, and the fruity-breathed emergency called ketoacidosis arrive — often in weeks.
iv.
The new baseline. Without external insulin, death. With it, a lifetime of replacing, by hand or pump, a hormone the body used to dose with millisecond precision.

§ 02 — History3,500 Years of Trying

Once, a diagnosis
was a death sentence.

For most of human history, Type 1 diabetes was an obituary with a countdown. The only question was how long. The story below spans the Ebers Papyrus to CRISPR — every dot a life extended.

1552 BC
Antiquity
The Ebers Papyrus

Ancient Egyptian physicians describe a mysterious condition of "too-great emptying of urine" — the first written record of what we now recognize as diabetes. Treatment: wheat grains, lead, and earth.

~200
Naming
"Diabetes" — to flow through

Greek physician Aretaeus of Cappadocia names the condition, observing that patients seemed to melt away into their own urine. The name sticks for two millennia.

1889
Localized
Minkowski & von Mering's dog

Two German researchers remove a dog's pancreas to study digestion. The dog develops diabetes. The source of the disease, after thousands of years, has an address.

1910
Named
Sharpey-Shafer coins "insulin"

The missing pancreatic substance gets a name — from the Latin insula, for island, after the pancreatic islet cells it was presumed to come from. Finding it is another matter.

1921
The Breakthrough
Banting, Best, Macleod & Collip

In a Toronto lab, a Canadian surgeon, a medical student, a professor, and a biochemist isolate insulin from dog pancreases. Early batches look like "thick brown muck." Collip purifies it.

1922
First Life Saved
Leonard Thompson, 14

January 11th. A dying Toronto teenager weighing 29kg receives the world's first human insulin injection. The first dose, impure, fails. Twelve days later, a purer dose restores him. Banting and Macleod receive the Nobel Prize within 18 months — still the fastest ever for a medical breakthrough.

1923
Access
Sold to the University for $1

Banting, Best and Collip sell their insulin patent to the University of Toronto for a single dollar each. They want no one excluded by price. Eli Lilly begins mass production.

1978
Synthetic
Human insulin, made by bacteria

Genentech engineers E. coli to produce human insulin — the first commercial recombinant-DNA drug. By 1982, Humulin replaces the cow and pig pancreases that had been supplying the world.

1999
Monitoring
Continuous glucose monitors

The first CGM is approved. Instead of pricking a finger 6 times a day, a sensor under the skin reads glucose every few minutes. Combined with pumps, this eventually becomes an "artificial pancreas."

2022
Delay
Teplizumab — the first to prevent

The FDA approves the first drug that can delay the onset of Type 1 diabetes in at-risk patients by an average of two years. Not a cure — but the first time we intervened upstream of the attack.

2024
Proof of Cure
Stem cells make insulin, in humans

A 25-year-old woman in China, infused with islet cells grown from her own reprogrammed stem cells, begins producing her own insulin again — becoming the first person functionally cured by stem-cell therapy. Vertex Pharma announces similar results in 12 more.

2025
Ongoing
19 out of 19 mice, cured

Stanford researchers cure autoimmune diabetes in every mouse they try, using a gentle blood-stem-cell plus islet transplant. Translation to humans now within reach. The 104-year story continues.

"We need not insulin, but the cells that make it."
— Douglas Melton, Harvard Stem Cell Institute

§ 03 — ComplexityWhy It's So Hard To Cure

One disease,
many locked doors.

Replacing insulin kept people alive — but did nothing to stop the immune attack, restore the pancreas, or match the exquisite moment-to-moment precision of a healthy body. Every cure attempt has had to solve at least three of these problems at once.

01

The immune system won't forget.

Even if you grew a whole new pancreas, the immune system — trained to see beta cells as enemies — would destroy it again. You have to re-educate immunity itself.

02

Insulin is narrow, and death is on both sides.

Too little: organs fail over years. Too much: brain damage within minutes. A healthy pancreas dosed by milligrams, per second. A syringe can only approximate.

03

We cannot find the trigger.

A virus? A gut bacterium? A random recombination in the thymus? A century of studies points in many directions. Without a cause, prevention stays out of reach.

04

Beta cells are uniquely fragile.

Other organs regenerate. Beta cells barely do. Growing enough of them in a lab — billions, the same size, the same behavior — is an industrial problem nearly as hard as the biological one.

05

Immunosuppression trades one illness for another.

We can transplant islet cells from organ donors today — but recipients must take immunosuppressants for life, swapping diabetes for vulnerability to infection and cancer. A half-cure.


§ 04 — The Daily RealityA Day In Numbers

The pancreas you'll
need to be.

Without a functioning pancreas, every meal, every workout, every night of sleep becomes a calculation. Below: one real day's blood glucose for a person with T1D (anonymized, hypothetical reconstruction), versus the narrow band a healthy body holds without you ever noticing.

24 hours of blood glucose

mg/dL · one person with Type 1 · vs. healthy target band
T1D reading
Healthy range
Meal / bolus
400 300 200 100 0 TARGET · 70–180 mg/dL BREAKFAST LUNCH DINNER SPIKE · 340 STRESS RESPONSE LOW · 58 · JUICE! 00:00 06:00 09:00 12:00 18:00 21:00 24:00
SOURCE: ILLUSTRATIVE TRACE BASED ON PUBLISHED CGM CASE DATA · THE JOB OF A T1D PATIENT IS TO HAND-STEER THE RED LINE INTO THE BLUE BAND, EVERY HOUR, FOR LIFE.
~9M
people worldwide live with Type 1 diabetes.
IDF / WHO 2024
the global incidence has roughly quadrupled since 1950 — no one knows exactly why.
Epidemiological reviews
180+
daily decisions a person with T1D makes about food, activity and insulin — most people make zero.
Stanford Medicine
$0
price Banting, Best and Collip charged the world for their insulin patent.
University of Toronto, 1923

§ 05 — The FrontierWho Is Racing To The Cure

Six groups, five strategies,
one moving finish line.

For the first time in 104 years, the question has shifted from can we manage this to can we end it. Below is a snapshot of the labs and companies with the most momentum as of 2025–2026.

Stem cells

Vertex Pharmaceuticals

Doug Melton · Harvard spinout

Their therapy VX-880 grows insulin-producing islet cells from embryonic stem cells and infuses them into patients. First-in-human trials show sustained insulin production in 12 people — the first real demonstration of stem-cell replacement for T1D.

→ Phase 1/2 · Ongoing
Autologous cells

Deng Hongkui Lab

Peking University · Tianjin

In 2024, reprogrammed a 25-year-old patient's own cells into islets and implanted them. She is the first person cured by her own stem cells — no donor, no rejection, no lifelong immunosuppression needed.

→ Case Report · Cell, 2024
Immune reset

Stanford Medicine

Seung Kim · Judith Shizuru

A gentle blood-stem-cell + islet transplant that builds a hybrid immune system — donor + recipient — and stops the autoimmune attack at its source. Cured 19/19 diabetic mice in 2025. Tools already exist clinically; human trials next.

→ J. Clin. Invest., Nov 2025
Prevention

Provention Bio / Sanofi

Teplizumab · FDA-approved 2022

The first drug ever to delay the onset of T1D in at-risk children. A 14-day IV course blunts the T-cell attack and buys patients, on average, an extra 2+ years before insulin dependence.

→ Approved · Expanding trials
Engineered immunity

Ferreira Lab · MUSC

Leonardo Ferreira · w/ UF & UMass

Engineering regulatory T-cells (Tregs) with chimeric antigen receptors (CARs) that act as bodyguards — guarding transplanted islet cells from autoimmune destruction without systemic immunosuppression.

→ Preclinical · Breakthrough T1D funded
Smart insulin

T1D Grand Challenge

Diabetes UK · Steve Morgan Foundation

£50M global push funding 23 projects across 49 institutions in 8 countries. Focus: glucose-responsive "smart" insulins that activate only when sugar is high, plus insulin-glucagon hybrids that prevent dangerous lows.

→ 189 researchers · Live

A global effort, unevenly distributed.

Research concentrates in the US, Canada, UK and China. Care — and access to modern insulin — does not. In parts of sub-Saharan Africa, life expectancy after diagnosis can still be measured in months. The century since Banting has unevenly reached everyone.

TORONTO BOSTON STANFORD MUSC LONDON BEIJING FIG. 3 — MAJOR ACTIVE T1D RESEARCH HUBS · ILLUSTRATIVE
§ CODA

104 years after the brown muck,
we may finally be close.

The story began with a surgeon waking at 2 a.m. to scribble a hypothesis, and a 14-year-old boy given a second chance on a Toronto hospital ward. It continues now — in South Carolina, in Palo Alto, in a small lab in Beijing — with scientists trying not just to treat the body's accidental war on itself, but to end it.

The finish line moves. So do they.