The main role of the immune system is to fight off foreign invaders, for example bacteria or viruses. In autoimmune conditions, the body’s own immune system attacks healthy cells, tissues, or organs, which can result in inflammation and damage. Along with type 1 diabetes, there are over 80 autoimmune diseases. There are some more common (i.e. diabetes, rheumatoid arthritis) than others (i.e. lupus, vasculitis).
For people who have an autoimmune disease, they are at an increased risk of developing other autoimmune conditions. So, if you have type 1 diabetes, then you are susceptible to another autoimmune disease. This also means that if you don’t have type 1 diabetes, but you have another autoimmune condition, you are susceptible to developing type 1 diabetes. The most common autoimmune diseases that are associated with type 1 diabetes is coeliac disease and Hashimoto's thyroiditis.