Why does type 2 diabetes weaken the immune system?

Type 2 diabetes is a metabolic disorder that can lead to serious health problems. With type 2 diabetes, the body doesn't use insulin as well as it should. One of the main complications of type 2 diabetes is an impaired or weakened immune system, making you more vulnerable to infections and other diseases.

What is the immune system?
The immune system is the collection of cells and organs that work together to fight disease. The organs of the immune system are your thymus, spleen, lymph nodes and bone marrow. These organs make white blood cells (WBCs), including T-cells and B-cells. These WBCs help protect against infections from viruses and bacteria. The spleen and lymph nodes produce antibodies that destroy germs or mark them for destruction by other WBCs. Other parts of the immune system are phagocytes, which engulf bacteria or any harmful substance to the body, as well as natural killer cells (NKC) that attack cells in the body with abnormal proteins.

How do WBCs work?
The cells of the immune system have a particular structure. The T-cells, in particular, have two molecules that stick out from their central body or nucleus area. These are called 'tails', and they are like paddle wheel-like appendages that move around the cells of the immune system using motors to push them in different directions.
So how does this affect the immune system? If you do not make enough insulin, your body cannot use the glucose you eat as an energy source, so it uses it instead to make chemicals needed by the immune system. These chemicals are called 'cytokines', and one of the main ones is interleukin 6 (IL-6). IL-6 then causes other WBCs to increase their production of cytokines. This boosts your immune system, but it also means that the cells that make IL-6 are less active in fighting infections. So your risk of getting infections increases as a result.

How does this affect lead to type 2 diabetes? Type 2 diabetes actually has two different causes. One cause is genetic, which means you inherit it from your parents. The other cause is that the pancreases make insulin less effective for the body to use glucose for energy. This means you need to eat more to supply the same power as insulin. The better your body responds to eating, the more glucose your pancreas has to make, so it becomes harder and harder to maintain stable blood sugar levels.

In addition, cells that make IL-6 or cytokines are released into your bloodstream when you are stressed, so high levels of these cytokines can be found in people with type 2 diabetes compared with people without it. Stress also causes T-cells and B-cells not to work well, so they don't produce as many cytokines. Cytokines also act directly on the pancreas and make it harder for insulin-producing cells to function.

As you can see, the immune system is not only your protector against infections but can also cause complications in type 2 diabetes. The next time you get a cold or flu, it could be that you have diabetes and your body is not producing enough IL-6 to fight off these infections!

So it appears that the body is producing cytokines to protect against infections. Still, at the same time, these cytokines are preventing the body from using insulin effectively, which results in diabetes. Also, stress causes the body not to produce IL-6, so the immune system becomes weaker and less able to fight infections (since it makes fewer cytokines to keep you healthy).