Homogeneous immunofluorescence staining pattern of double stranded DNA antibodies on HEp-20-10 cells. Interphase cells show homogeneous<unk>  staining while mitotic cells show staining of the condensed chromosome regions. Antinuclear antibodies <unk> s, also known as antinuclear factor or ANF) are autoantibodies that bind to contents of the cell nucleus. In normal individuals, the immune system produces antibodies to foreign proteins (antigens) but not to human proteins (autoantigens). In some cases, antibodies to human antigens are produced. There are many subtypes of<unk> s such as anti-Ro antibodies, anti-La antibodies, anti-Sm antibodies, anti-nRNP antibodies, anti-Scl-70 antibodies, anti-dsDNA antibodies, anti-histone antibodies, antibodies to<unk>  pore complexes, anti-centromere antibodies and anti-sp100 antibodies. Each of these antibody subtypes binds to different proteins or protein complexes within the nucleus. They are found in many disorders including autoimmunity, cancer and infection, with different prevalences of antibodies depending on the condition. This allows the use of<unk> s in the diagnosis of some autoimmune disorders, including systemic lupus erythematosus, Sjögren syndrome, scleroderma, mixed connective tissue disease, polymyositis, dermatomyositis, autoimmune hepatitis and drug induced lupus. The<unk>  test detects the autoantibodies present in an individual's blood serum. The common tests used for detecting and quantifying<unk> s are indirect immunofluorescence and enzyme-linked immunosorbent assay (ELISA). In immunofluorescence, the level of autoantibodies is reported as a titre. This is the highest dilution of the serum at which autoantibodies are still detectable. Positive autoantibody titres at a dilution equal to or greater than 1:160 are usually considered as clinically significant. Positive titres of less than 1:160 are present in up to 20% of the healthy population, especially the elderly. Although positive titres of 1:160 or higher are strongly associated with autoimmune disorders, they are also found in 5% of healthy individuals. Autoantibody screening is useful in the diagnosis of autoimmune disorders and monitoring levels helps to predict the progression of disease. A positive<unk>  test is seldom useful if other clinical or laboratory data supporting a diagnosis are not present.
Anti-nuclear antibody
Anti-neutrophil cytoplasmic antibody
Antisperm antibodies
Anti–citrullinated protein antibody
Anti-LKM antibody
C-ANCA
Anti-malignin antibody
Anti–Saccharomyces cerevisiae antibody