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HelpTest Code AUTJO Jo 1 Antibodies, IgG, Serum
Additional Codes
| Mayo Test ID |
|---|
| JO1 |
Reporting Name
Jo 1 Ab, IgG, SUseful For
Evaluating patients with clinical features of idiopathic inflammatory myositis, especially those with clinical features suggestive of anti-synthetase syndrome or interstitial lung disease
Testing Algorithm
For more information see Connective Tissue Disease Cascade.
Method Name
Multiplex Flow Immunoassay
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
SerumSpecimen Required
Collection Container/Tube:
Preferred: Serum gel
Acceptable: Red top
Submission Container/Tube: Plastic vial
Specimen Volume: 0.5 mL
Collection Instructions: Centrifuge and aliquot serum into a plastic vial.
Specimen Minimum Volume
0.35 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Serum | Refrigerated (preferred) | 21 days | |
| Frozen | 21 days |
Reject Due To
| Gross hemolysis | Reject |
| Gross lipemia | Reject |
| Gross icterus | OK |
| Heat-Treated | Reject |
Special Instructions
Reference Values
<1.0 U (negative)
≥1.0 U (positive)
Reference values apply to all ages.
Day(s) Performed
Monday through Saturday
CPT Code Information
86235
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| JO1 | Jo 1 Ab, IgG, S | 33571-1 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| JO1 | Jo 1 Ab, IgG, S | 33571-1 |
Clinical Information
Based on their specificity, autoantibodies in idiopathic inflammatory myopathies (IIM) are grouped into myositis specific (MSA) and myositis associated autoantibodies (MAA).(1-3) Among the MSA, autoantibodies against aminoacyl-tRNA synthetases (aaRSs) represent the most common antibodies and can be detected in 25% to 35% of patients with mainly anti-synthetase syndrome (ASSD).(1-4) ASSD is an autoimmune disease characterized by the presence of autoantibodies targeting one of several aaRSs along with clinical features including interstitial lung disease, myositis, Raynaud's phenomenon, arthritis, mechanic's hands, and fever.(3,4) The family of aaRSs consists of highly conserved cytoplasmic and mitochondrial enzymes, one for each amino acid, which are essential for the RNA translation machinery and protein synthesis. Along with their main functions, aaRSs are involved in the development of immune responses, regulation of transcription, and gene-specific silencing of translation.(4)
Anti-Jo-1 autoantibody is the most frequently detected anti-aaRS antibody in ASSD and targets the histidyl tRNA synthetase which catalyses the binding of the histidine to its cognate tRNA during protein synthesis.(4,5). Other described anti-aaRSs reported in ASSD include PL-7 (threonyl), PL-12 (alanyl), OJ (isoleucyl), EJ (glycyl), KS (asparaginyl), Zo (phenylalanyl) and Ha (tyrosyl).(4) The presence these autoantibodies has become a key feature for classification and diagnosis of IIM and is increasingly used to define clinically distinguishable IIM subsets. Each anti-ARS antibody seems to define a distinctive clinical phenotype.(3)
In addition to the characteristic features associated with the presence of anti-Jo-1 antibodies in patients with ASSD, testing for anti-aaRS autoantibodies including anti-Jo-1 antibody maybe indicated with cytoplasmic speckled pattern using HEp-2 substrate by indirect immunofluorescence assay.(6,7) In the context of ASSD, their presence may be associated with positivity for anti-Ro52 antibodies which is an MAA.(8) In routine clinical testing, anti-Jo-1 antibody testing maybe performed using a variety of solid-phase immunoassays such as the enzyme-linked immunosorbent assay, line immunoassay, chemiluminescence immunoassay, fluorescent enzyme immunoassay, and multiplex immunoassay such as the BioPlex.(6,9,10) The performance characteristics of these assays for the detection of anti-Jo-1 antibody have not been extensively investigated to establish comparability.(9,10)
For more information see Connective Tissue Disease Cascade.
Interpretation
A positive result for anti-Jo 1 antibody is suggestive of anti- synthetase syndrome or may indicate a risk for myositis with or without interstitial lung disease.
Cautions
A negative test for Jo 1 antibodies does not exclude the diagnosis of idiopathic inflammatory myositis.
Method Description
Recombinant Jo 1 antigen is coupled covalently to polystyrene microspheres, which are impregnated with fluorescent dyes to create a unique fluorescent signature. Jo 1 antibodies, if present in diluted serum, bind to the Jo 1 antigen on the microspheres. The microspheres are washed to remove extraneous serum proteins. Phycoerythrin (PE)-conjugated antihuman IgG antibody is then added to detect IgG anti-Jo 1 bound to the microspheres. The microspheres are washed to remove unbound conjugate, and bound conjugate is detected by laser photometry. A primary laser reveals the fluorescent signature of each microsphere to distinguish it from microspheres that are labeled with other antigens, and a secondary laser reveals the level of PE fluorescence associated with each microsphere. Results are calculated by comparing the median fluorescence response for Jo 1 microspheres to a 4-point calibration curve.(Package insert: Bioplex 2200 ANA Screen. Bio-Rad Laboratories, 02/2019)