Test Directory

• Jo-1 Ab
• Pl-7 Ab
• Pl-12 Ab
• EJ Ab
• OJ Ab
• SRP Ab
• Mi-2 Alpha Ab
• Mi-2 Beta Ab
• MDA5 Ab
• TIF1 Gamma Ab
• NXP-2 Ab

Myositis-specific autoantibodies (MSAs) are highly selective, usually exclusive and are associated with particular clinical phenotypes within the myositis spectrum. Myositis-specific autoantibodies to cytoplasmic enzymes that catalyze the binding of specific amino acids to their cognate tRNA define the anti-synthetase syndrome characterized by myositis and lung inflammation, and include autoantibodies to Jo-1 (antihistidyl-tRNA synthetase), PL-7 (threonyl), PL-12 (alanyl), EJ (glycyl), and OJ (isoleucyl).

A further subset of myositis patients is characterized by the presence of autoantibodies directed against the signal recognition particle (SRP). Autoantibodies to Mi-2 (Mi-2/nucleosome remodeling and deacetylase (NuRD) complex) are detected in patients with hallmark dermatomyositis features. Autoantibody to a cytoplasmic 140-kDa protein, melanoma-differentiation associated gene 5 (MDA5), also known as anti-CADM140, identified patients with clinically amyopathic dermatomyositis (CADM) and rapidly progressive lung disease.

Autoantibodies to transcriptional intermediary factor 1-gamma (TIF-1 y), a p155/140 nuclear protein involved in cellular differentiation, have been reported in adult and juvenile dermatomyositis; in adults, it is associated with malignancy. Autoantibodies to nuclear matrix protein NXP-2, another 140-kDa protein, is found in juvenile dermatomyositis (JDM). Anti-TIF-1 y and anti-NXP-2, two novel serological subsets in JDM, occur collectively in >40% of children and appear to identify those with more severe disease.

Specimen Type: Serum

Preferred Collection Container: Red Top, Plain

Alternate Collection Container: Gold Top, Serum Separator

Desired Specimen Volume: 0.5 mL

1. Collect a red top, plain tube via venipuncture.

1. Separate serum from cells.
2. Transfer 0.5 mL of serum to a clear aliquot tube (screw cap).

For patients receiving STRENSIQ, consideration should be given to using alternate methods.

Transport to the laboratory refrigerated.

See patient report.

Administration of STRENSIQ may interfere in certain assays and may falsely elevate values.