ORGENTEC Autoimmunity Blog

Covering Autoimmune Diseases

Jo-1 antibodies

Jo-1 autoantibodies are also called histidyl-tRNA synthetase antibodies or polymyositis antibodies. They are an acknowledged marker for the disease polymyositis.

Testing for these autoantibodies is advisable when patients are demonstrating signs and symptoms compatible with connective tissue disease, such as muscle pain and limb weakness, Raynaud’s syndrome, arthritis, and concomitant pulmonary signs and symptoms.

The autoantigen responsible is the Jo-1 antigen, also called histidyl tRNA synthetase. The autoantigen is member of the amino acyl-tRNA synthetase family of enzymes and part of the ENA set. Histidyl tRNA synthetase is a cytoplasmic enzyme found in all nucleated cells. During protein biosynthesis histidyl tRNA synthetase catalyses the binding of the amino acid histidine to transfer RNA (tRNA). Jo-1 antibodies bind to conformational epitopes of the enzyme protein, inhibiting its catalytic activity.

Most commonly Jo-1 antibodies occur in myositis patients with interstitial lung disease. In patients with interstitial pulmonary fibrosis and symmetrical polyarthritis Jo-1 antibodies are detectable in up to 50% of cases.


Tests offered by ORGENTEC Diagnostika


ANA Detect (ORG 600, ORG 200)
ANAcombi (ORG 539)
ANAscreen (ORG 538, ORG 238)
Anti-Jo-1 (ORG 513, ORG 213)
ENA-6-Profile (ORG 546)
ENAcombi (ORG 514)
ENAscreen (ORG 506, ORG 206)


ANA-9-Line (ORG 710)
Myositis plus (ORG 760)
Nucleo-9-Line (ORG 711)

Indirect Immunofluorescence Assay (IFA):

Anti-Nuclear Antibodies HEp-2 (ANA-HEp-2) (ORG 870, ORG 800)


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