Autoimmunity laboratory

Immunofluoresence

Summary

Science

Clinical

Science

In patients with a suspected autoimmune disease it is often useful to identify the presence of autoantibodies that are directed against specific tissues. These autoantibodies are often not the cause of the disease but can be useful markers of disease association with varying degrees of specificity. Patient serum is separated from the red blood cells and then applied directly onto a specific tissue section (substrate) mounted on a microscope slide, the type of tissue substrate is chosen as having relevance to the suspected disease. After a period of incubation, the serum is washed off leaving any autoantibodies bound to specific antigens on the substrate. The next step is to add a fluorescently labelled antibody that will bind to all human antibodies, thereby tagging and fluorescently identifying any of the patient’s antibodies that have bound to the tissue. After a final incubation any excess conjugate is washed off and the sample exposed to UV light under a specialised microscope. The fluorescent label absorbs UV light, becomes excited and emits light at a different wavelength (green light) so areas on the substrate where patient antibodies have bound can be visualised. Patient samples are compared with negative and positive controls to identify where significant autoantibody presence could indicate a specific disease.

• Background
• Clinical