Anti-nuclear antibodies

In medicine, especially rheumatology, anti-nuclear antibodies are "autoantibodies directed against various nuclear antigens including DNA, RNA, histones, acidic nuclear proteins, or complexes of these molecular elements. Antinuclear antibodies are found in systemic autoimmune diseases including systemic lupus erythematosus, Sjogren's syndrome, scleroderma, polymyositis, and mixed connective tissue disease.

Screening tests

A first and indirect measurement of these antibodies was the 1940-vintage lupus cell preparation, a microscopic procedure no longer used. In modern practice, the basic screening test is the anti-nuclear antibody titer (ANA). While not specific, a high ANA values suggests an autoimmune disease is present; it does not, however, exclude them. High values then justify more specific tests:

Its sensitivity, in specific diseases, is:

• Autoimmune
  • Systemic lupus erythematosus 96-100%
  • Scleroderma 60-80%
  • Mixed connective tissue disease 100%
  • Polymyositis and dermatomysitis 61%
  • Rheumatoid arthritis 52&
  • Rheumatoid vasculitis 30-50%
  • Sjogren's syndrome 40-70%
  • Drug-induced lupus 100%
  • Discoid lupus 15%
  • Pauciarticular juvenile chronic arthritis 71%
• Non-rheumatic
  • Hashimoto's thyroiditis 46%
  • Graves' disease 50%
  • Autoimmune hepatitis 100%
  • Primary autoimmunie cholangitis 100%
  • Primary pulmonary hypertension 100%

Specific clinical tests

• Anti-single-stranded DNA antibodies (ssDNA)
• Anti-double-stranded DNA antibodies (dsDNA)
• Antihistone antibodies
• Anti-centromere antibodies are present principally with limited cutaneous systemic sclerosis, especially those presenting with the CREST syndrome; they are seen in subtypes of systemic sclerosis, such as Reynaud's phenomenon. When the value is elevated without features of systemic sclerosis, another and likely serious connective tissue disorder may be present.
• Anti-Smith (anti-Sm)
• Anti-ribonucleoprotein antibodies (anti-RNP)
• Antiphospholipid antibodies