Anti-Jo-1 antibody positive

Introduction The Jo-1 antigen is a histidyl tRNA synthetase which appears as a small molecule ribonucleoprotein (scRNPs) in the cytoplasm and has a molecular weight of 50 kD, which is one of aminoacyl tRNA synthetases. Anti-Jo-1 antibody has strong specificity for the diagnosis of polymyositis and is currently recognized as a serum-labeled antibody to polymyositis (PM). The positive rate in polymyositis (PM) is about 25%.

Cause

The positive rate in polymyositis (PM) is about 25%. The positive rate in dermatomyositis (DM) was 7.1%. In patients with PM/DM with pulmonary interstitial lesions, the positive rate was as high as 60%.

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67% of anti-Jo-1 antibody positive patients have HLA-DR3 antigen. Other connective tissue diseases were negative. In anti-JO-1 and anti-SSA binomial, about 80% of patients with polymyositis and cutaneous hepatitis have Sjogren's syndrome. However, two positive anti-JO-1 and anti-RNP patients have been clinically found to have Raynaud's phenomenon. Anti-Jo-1 antibody syndrome: anti-Jo-1 antibody positive, acute fever, symmetrical arthritis, "technician", Raynaud's phenomenon, myositis, pulmonary interstitial lesions.

Differential diagnosis

Differential diagnosis of anti-Jo-1 antibody positive:

(1) Anti-Sm antibody: is a specific antibody against SLE. The Sm antigen is a U-type small molecule nuclear ribonucleoprotein (UsnRNP), and the molecular weight of the antigenic protein is 29KD, 28KD, and 13.5KD. The positive rate in SLE was 30.2%. Although the sensitivity is lower, the specificity is higher. Of all anti-Sm positive cases, 92.2% were SLE. Therefore, the anti-Sm antibody is a labeled antibody of SLE. In addition, it has been found that after SLE patients change from active to remission, lupus cells can be negative, ANA, anti-DNA antibody titers can be reduced, but Sm antibodies still exist. Therefore, it has a certain significance for early, atypical SLE or retrospective diagnosis after treatment remission. Sm antibody and SnRNP are different antigenic sites in the same molecular complex, so anti-Sm antibody rarely appears alone, it is often accompanied by U1RNP antibody, about 60% anti-U1RNP antibody cross-reacts with 28/29KD in anti-Sm antibody . Anti-Sm antibody positive is associated with anti-U1RNP antibodies, while anti-U1RNP antibodies can be present alone.

(2) Anti-SSA/Ro antibody: Anti-SSA/Ro antibody R0, SSA antigens are immunologically identical, that is, have common antigenic determinants. SSA/Ro is a small molecule cytoplasmic ribonucleoprotein (scRNPs), a complex of proteins and small molecule ribonucleic acids. The antigen is a protein containing Y-YRNA, which is more abundant in the cytoplasm and has a molecular weight of 52 KD and 60 KD. The 52KD peptide band is associated with Sjogren's syndrome (SS), while the 60KD polypeptide band is more present in SLE patients. Anti-SSA antibodies are often negative in ANA assays using murine liver as a substrate, while Hep-2 cells are substrates and ANA is often positive. Anti-SSA antibodies are mainly found in primary Sjogren's syndrome, and the positive rate is as high as 60% to 75%. In addition, anti-SSA antibodies are often associated with subacute cutaneous lupus erythematosus, anti-nuclear antibody-negative lupus, neonatal lupus, etc. (SSA antibodies can enter the fetus through the placenta to cause neonatal lupus syndrome). SSA antibodies are associated with a wide range of photoallergic dermatitis symptoms.

(3) Anti-SSB/La/Ha antibody: anti-small molecule nuclear ribonucleoprotein (snRNP). The antigen is a small RNA phosphoprotein in the transcription of RNA polymerase. Its molecular weight is 48KD, 47KD, 45KD, of which 48KD is more specific. It is specific for the diagnosis of Sjogren's syndrome. The anti-SSB/La/Ha antibody SSB/La/Ha antigen is immunologically identical. Anti-SSB positive is almost always positive with anti-SSA antibody. Anti-SSB antibody is more specific than SSA antibody for diagnosis of Sjogren's syndrome. It is a serum-specific antibody to Sjogren's syndrome. The positive rate of primary Sjogren's syndrome is about 40%. Other autoimmune diseases, such as anti-SSB antibodies, are often accompanied by secondary Sjogren's syndrome. A large number of lymphocytes infiltrated in the salivary glands and labial glands.

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