Immunology is the study of the immune system, ranging from its normal physiological function through to malfunctions which can lead to immunological diseases. Disorders that result from inappropriate activation of the immune system are referred to as autoimmune diseases and these result from the immune system mounting a defence against host cells or tissues - with the body effectively attacking its own proteins by creating autoantibodies and causing inflammation, itself a natural critical response to potential danger signals and damage in organs.
When the immune system becomes inappropriately activated it can lead to one of multiple autoimmune diseases, with each affecting a different type of cell or tissue, and they are classified as either organ-specific or systemic. For example, type I or insulin-dependent diabetes mellitus, in which β islet cells in the pancreas are destroyed by an autoimmune response, is an organ-specific disease. Rheumatoid arthritis primarily affects synovial joints, where a chronic inflammatory response results in the degradation of cartilage and inflammation of the joint but as it can also manifest in the lungs and skin, rheumatoid arthritis is classed as a systemic autoimmune disease. These debilitating diseases take an immense toll on quality of life. Many are only poorly managed by existing treatments that provide only symptomatic relief with the mechanisms behind the immune response still not well understood.