However, in certain cases and in certain individuals, our immune system can actually lose its natural immunological tolerance to the healthy cells of our body. And what that means is our immune system can no longer distinguish or differentiate between self antigens of healthy cells and pathogenic antigens. And at this point, the white blood cells will begin to attack not only the pathogens and infected cells, but also the healthy cells of our body. And this condition in which our immune system loses its natural immunological tolerance to our healthy cells is known as autoimmunity or autoimmune disease. Now, what are some examples of autoimmune diseases? Well, multiple sclerosis is one.