Anti-Jo1 antibodies

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Anti-Jo 1 is a myositis -specific antibody from the family of antisynthetase antibodies that was first identified in 1980 . It is associated with the so-called antisynthetase syndrome (ASA), ensures the diagnosis of polymyositis and is detected by ELISA . The name is derived from John P., the first patient in whom such an antibody was detected.

Emergence

It is currently unclear which mechanism leads to the formation of this antibody. One hypothesis states that it is a molecular mimicry phenomenon in the course of an infection with Picorna viruses . The organism forms an antibody that is directed both against an enzyme of these viruses and against an essential component of human protein synthesis ( histidyl-tRNA synthetase ). It has been observed that anti-Jo-1 antibodies are switched in their class during the course of the disease and experience an increase in their affinity. It is therefore assumed that this process is based on a T-cell -mediated immune response.

meaning

An increased anti-Jo-1 antibody level in the serum can be observed in about 20% of the cases of dermatomyositis and polymyositis . While Anti-Jo 1 is particularly specific for polymyositis, other antisynthetase antibodies, such as anti-OJ and anti-PL12, are more characteristic of dermatomyositis. However, it is not clear whether anti-Jo-1 antibodies are causally involved in the development of the diseases mentioned above.

Measurement

The detection of the anti-Jo-1 antibody in the serum is carried out in a laboratory using ELISA. A recombinantly produced histidyl-tRNA synthetase serves as the antigen for this. The sensitivity and specificity of this test are almost 100%, although it should be noted that this only means the detection of antibodies and not the detection of disease. In the past, detection was achieved by means of double diffusion using a bovine liver or thymus antigen.

Anti-Synthetase Syndrome

A separate syndrome has now been defined, the so-called anti-synthetase syndrome (ASA). It is described as an idiopathic inflammatory myopathy and chronic, systemic autoimmune disease with the presence of antisynthetase antibodies such as anti-Jo 1 are the Parts of this symptom complex: myositis , interstitial lung disease , arthritis , Raynaud's phenomenon , fever and hyperkeratosis of the hands ("mechanic hands").

literature

  • KB Stone et al .: Anti-Jo-1 antibody levels correlate with disease activity in idiopathic inflammatory myopathy . In: Arthritis & Rheumatism . tape 56 , no. 9 , 2007, p. 3125-3131 .
  • FW Miller et al .: Origin and regulation of a disease-specific autoantibody response. Antigenic epitopes, spectrotype stability, and isotype restriction of anti-Jo-1 autoantibodies. In: The Journal of Clinical Investigation . tape 2 , no. 85 , 1990, pp. 468-475 .
  • WJ Van Venrooij: Manual of biological markers of disease . 1st edition. Kluwer Academic Publishers, Dordrecht NL 1993, ISBN 978-0-7923-2219-1 .
  • EM Tan et al .: A critical evaluation of enzyme immunoassays for detection of antinuclear autoantibodies of defined specificities. I. Precision, sensitivity, and specificity . In: Arthritis & Rheumatism . tape 42 , no. 3 , 1999, p. 455-463 .

Individual evidence

  1. ↑ Antisynthetase Syndrome . orpha.net; Retrieved May 5, 2011.