But we do have some idea. So some possibilities that basically that cause autoimmunity might be a genetic mutation on our DNA in a section that codes for some type of important component of our immune system. For example, the major histocompatibility complex as we'll see in just a moment. Another fact that that might lead to autoimmunity are infections that we experience as a result of some type of pathogens. And we'll see what that is in just a moment. Another factor might be damage to immunologically privileged sites and we'll see what that means in just a moment.