Autoimmunity is an abnormal biological process that can lead to pathological disease. It is caused when an immune system that normally recognises and destroys foreign invaders such as viruses and bacteria, ceases to recognise it’s own tissues as “self” and attacks them causing the breakdown of structures and biological processes necessary for health. These degenerative processes can affect specific cells within the body as in Type 1 autoimmune diabetes where cells of the immune system infiltrate the pancreas and destroy the cells that produce insulin. Autoimmune processes can also be tissue specific such as in the disease Myasthenia gravis. In this disease antibodies, (specifically produced proteins of the immune system) bind to and block receptors in muscle that cause progressive muscle weakening. In the case of Systemic Lupus Erythamatosus the autoimmune process is more general in nature and can attack many different tissues causing a variety of symptoms including rashes, kidney damage, and light sensitivity. The causes of many autoimmune diseases are unclear although it is likely that they are due to a combination of factors including genetic disposition, specific viral infections and other environmental factors.
Within the autoimmunity laboratory we use a combination of technologies to look for specific markers of an autoimmune process to assist in the clinical diagnosis and management of disease. The specific markers are antibodies that usually interact with and bind to antigens (recognisable foreign structures) on bacteria to initiate clearance of infection but in autoimmune disease attach specifically to molecules on ‘self’ tissue. These “auto”antibodies can be pathogenic, meaning they are directly responsible for causing tissue damage and associated symptoms. Alternatively they can be just associated with a condition, that is caused by other immune mediators.
We use a variety of different technologies to look for specific disease associated antibodies however they all generally utilise the natural properties of antibody-antigen interactions. The main laboratory tests used are Immunofluoresence, Nephelometry and ELISA (Enzyme Linked Immunosorbent assay). Whilst the principles behind these tests have been around for quite a few years advances over recent years have led to higher accuracy and a greater amount of automation. These advances have meant that laboratory staff don’t simply have to be skilful scientists but also have to deal with many problems including questions about clinical interpretation, machine maintenance, issues of quality control as well as incidences of occasional technology malfunctions!