[Antinuclear antibodies in rheumatology]

Antinuclear antibodies are autoantibodies which are hallmarks of connective tissue diseases. They are directed against intracellular antigens. As a first step of the diagnostic procedure, screening for antinuclear antibodies is performed on HEp-2 cells as a substrate. Different immunofluorescence patterns such as homogeneous, rim-like or speckled can be seen and the antibody titer is determined. In a second step of the diagnostic procedure the antinuclear antibodies are differentiated into defined species. Systemic lupus erythematosus, Sjögren's syndrome, mixed connective tissue disease, polymyositis and dermatomyositis are characterized by disease-specific antibody profiles, which can be measured by different methods such as ELISA or immunoblotting. For clinical purposes the most important antinuclear antibodies are antibodies against double stranded DNA, Sm, RNP, SS-A, SS-B, centromere proteins and Jo-1. The importance of antinuclear antibodies lies in their disease-specific profiles which are helpful for diagnosis. At present, it is not known if antinuclear antibodies are involved in pathogenesis of connective tissue diseases.