Any Other Information
- What is Jo-1?
Jo 1 (histidyl tRNA synthetase) is a member of the amino acyl-tRNA synthetase family of enzymes which is found in all the nucleated cells. Jo 1 antibodies in patients with polymyositis are found to bind to conformational epitopes of the enzyme protein and inhibit its catalytic activity in vitro.
These autoantibodies demonstrate a diffuse granular cytoplasmic staining on Hep-2 cells. This antibody is directed against the histidyl-tRNA synthetase which is known to catalyse the binding of the histidine to its cognate tRNA during protein synthesis.
These antibodies can also be found in Dermatomyositis(DM), although less frequently than in Polymyositis(PM) and are rare in children with PM or DM and in other connective tissue diseases. ELISA, CIE and immune-blotting are highly specific and sensitive techniques for testing anti-Jo-1 antibodies.
Moreover, anti-Jo-1 serum levels are found to strongly correlate with disease activity representing a good marker for disease monitoring.
- What is JO-1 antibody test?
The Anti-Jo-1 antibodies blood test consists of a semiquantitative result of IgG class antibodies. Anti-Jo-1 antibodies are found in around 20 to 30 percent of patients with adult-onset polymyositis syndromes and are present in less than 65 percent of patients with both interstitial lung disease and myositis.
- What are the reference values for Jo-1?
<1.0 U (negative)
> or =1.0 U (positive)
These Reference values apply to all the ages.
- What are the details of the Assay for the antibody test?
Fluorescence enzyme linked immunoassay (Phadia Immunocap 250) Human recombinant Jo1 protein IgG antibodies.
5) What is the Anti-synthetase syndrome
Anti-synthetase syndrome is an autoimmune disease which is characterized by autoantibodies against one of many aminoacyl transfer RNA (tRNA) synthetases with clinical features that may include interstitial lung disease (ILD), non-erosive arthritis, myositis, Raynaud's phenomenon, unexplained fever and/or mechanic's hands. The features of mechanics hands include the following: hyperkeratosis, scaling, and fissuring affecting the phalanges of the hands. There is found to be a well-established association of anti-synthetase antibodies and the presence of ILD.
6) Is Anti-synthetase syndrome curable?
Anti-synthetase syndrome patients can go into remission, especially for those who have milder lung disease, but patients are more likely to remain symptom free while continuing the treatment. Flares may tend to occur when medications are tapered too rapidly.
7) What is myositis?
Myositis is the name for a group of rare conditions. The main symptoms include weak, painful or aching muscles. This may usually gets worse, slowly over time. The patient may also trip or fall a lot, and be very tired after walking or standing.
8) What is the treatment for Dermatomyositis(DM) and Polymyositis(PM)?
Despite having a limited number of randomized controlled studies, the mainstay of therapy for PM and DM is corticosteroids plus either methotrexate or azathioprine, according to literature. Other agents which are used with some success include drugs such as cyclosporine, tacrolimus, cyclophosphamide, intravenous immunoglobins, and rituximab. Frequently, weakness is found to improve more than pulmonary symptoms following treatment.
9) What is the pathology of myopathy with anti JO-1antibodies?
Myopathology in patients with anti-Jo-1 antibodies consistently includes fragmentation of the perimysial connective tissue and macrophage predominant inflammation in the perimysial connective tissue. Perifascicular myopathic changes, including atrophy, regenerating muscle fibres, and some muscle fibre necrosis, are seen most commonly in regions near the connective tissue pathology and are seen most prominent in patients with more severe weakness. Unlike many other inflammatory myopathies, inflammation in endomysial and perivascular regions are not common. By contrast with dermatomyositis, capillary density is usually normal.
10) How long a patient live with Antisynthetase syndrome?
In a 2015 survival analysis of 45 patients with anti-synthetase syndrome-Interstitial Lung Disease- 14% of patients had died at 5 years. Survivors more frequently presented with Jo-1 positivity and arthritis.
11) Is Antisynthetase syndrome a rare condition?
Antisynthetase syndrome is a rare disorder which is found to affect females twice as often as males.
12) What are the various tests that can measure JO-1 Antibodies?
ELISA, Counter current Immuno-Electrophoresis and immunoblotting are the highly specific and sensitive techniques for testing anti-Jo-1 antibodies.
13) What are the CT findings of Dermatomyositis(DM) and Polymyositis(PM)
Predominant high-resolution CT scan patterns include diffuse ground-glass opacity, reticular shadow, and consolidation with traction bronchiectasis. Distribution was basal-predominant peripheral and along the bronchovascular bundle.
14) What are the clinical features of Dermatomyositis (DM)?
According to literature, the classical cutaneous manifestations of DM include Gottron’s papules and heliotrope rash, but other features such as digital ulcers, photosensitivity, calcinosis cutis, the “shawl” and “V-neck” signs, cuticular hypertrophy, periungueal erythema, and “mechanic’s hands” might be present. In addition, extramuscular manifestations such cardiac, gastrointestinal, joint, and lung involvement might also occur.
15) What are the findings in patients who are positive for J0-1 antibodies?
According to literature, significantly increased prevalence of “mechanic’s hands,” as well as joint and lung involvements, and a reduced prevalence of facial erythema, “shawl” sign, and “V-neck” sign were found among some patients positive for anti-Jo-1 autoantibodies compared to anti-Jo-1-negative patients.
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