Is type 2 diabetes an autoimmune disease?

Historically, type 2 diabetes has always been recognized as a metabolic disorder, often triggered by lifestyle behaviors and genetics.

Unlike type 1 diabetes, which is an autoimmune disease (with no known prevention or treatment), prediabetes and type 2 diabetes have always been viewed by scientists as something to be “prevented.”

However, a growing body of research indicates that type 2 diabetes may in fact be an autoimmune disease that has the potential to dramatically alter the thought processes behind prevention and treatment.

So what does the research tell us?

In this article, we will examine whether type 2 diabetes is indeed an autoimmune disease.

What is type 2 diabetes?

Type 2 diabetes is a condition in which the body either does not produce enough insulin or has too much insulin resistance to properly process glucose from the bloodstream into the cells for energy.

It is becoming extremely common in the United States, where over a million new cases are diagnosed each year. It affects nearly 1 in 10 American adults.

Many people with type 2 diabetes can control their blood sugar with diet and exercise alone, but some people require oral medications such as metformin and sometimes even daily insulin injections to adequately control their blood sugar.

Prediabetes, a precursor to type 2 diabetes, develops when the body begins to become resistant to insulin, resulting in high blood sugar levels that are elevated but not high enough to warrant a diagnosis of type 2 diabetes.

Risk factors for type 2 diabetes include (but are not limited to) being overweight or obese, being over 45 years of age, having a family history of type 2 diabetes, pre-diabetes, or being sedentary.

Learn more: What’s the difference between type 1 diabetes and type 2 diabetes?


What does the research say? 
While research is preliminary and more is needed to officially reclassify type 2 diabetes as an autoimmune disease, type 1 and type 2 diabetes may have more in common than initially thought. 
According to a 2019 study, people with type 2 diabetes have autoimmune disease markers similar to those with type 1 diabetes. 
These tags include:

Changes in the number and function of immune cells
Remarkable antibody activity
Changes in the number of T cells 
Long-term inflammation in the body 

Another 2011 study found that lab mice susceptible to developing type 2 diabetes were able to prevent the onset of the disease when treated with an antibody called Anti-CD20 that targeted and eliminated mature B cells in the immune system, restoring blood sugar levels to levels to normal.
The researchers then studied 32 overweight or obese people and divided them into two groups (matched for height and weight): one group was insulin resistant and the other insulin sensitive. 
After studying the participants, it turned out that those who were insulin resistant actually developed antibodies against some of their own proteins, while people who were insulin sensitive did not. 
They found it highly suggestive that the development of insulin resistance, and thus pre-diabetes and type 2 diabetes, in humans is about the body targeting its own proteins, linking the concept of insulin resistance to autoimmunity. 
These findings could dramatically change the way scientists and doctors think about type 2 diabetes, its prevention and treatment. 

What could this mean for people with type 2 diabetes? 
If type 2 diabetes is indeed an autoimmune disease, it may respond to medications that help weaken the immune system, such as immunosuppressants, to prevent the disease from occurring. 
Anti-CD20, already available in the US under the trade names Rituxan and MabThera, is currently approved to treat certain autoimmune diseases in humans, but more research is needed to see if it can help prevent type 2 diabetes in humans, as it has done on mice. 
These drugs can target and eliminate immune cells that attack healthy tissue. 
Other researchers believe that there might eventually be a type 2 diabetes vaccine that would dampen the immune response, essentially preventing the disease from developing in the body, although these technologies are still a long way off. 
Learn more: Is type 2 diabetes reversible?

Application
In summary, the science behind whether type 2 diabetes is an autoimmune disease is evolving, but it would dramatically change the way scientists, doctors, and society at large think about, prevent, and treat this disease. 
The development of type 2 diabetes is so often blamed on the individual, but reclassifying it as an autoimmune disease may help eliminate some of the stigma attached to the disease. 
Moreover, the prevention of type 2 diabetes could change dramatically from simply recommending changes in diet and exercise to potentially treating patients with immunosuppressive therapy and even administering the vaccine on a larger scale to those at highest risk. 
More research is needed to find the direct cause of both type 1 and type 2 diabetes, but future treatments and prevention may look very different than today. 
However, until that date, preventing and treating non-insulin-dependent type 2 diabetes will require controlling blood sugar in more traditional ways, including increasing physical activity levels and controlling diet. 
Talk to your doctor about the most appropriate treatment plan if you have recently been diagnosed with type 2 diabetes.