How does the ANA profile aid in the diagnosis and management of SLE and related juvenile systemic CTDs?
Although a negative ANA profile does not rule out any of the juvenile systemic CTDs, a positive ANA profile can be extremely useful in making a specific diagnosis. In particular, anti-dsDNA and anti-Smith (anti-Sm) antibodies are specific for SLE; high titers of anti-ribonucleoprotein antibody are suggestive of MCTD; and anti-Ro (SS-A) and/or anti-La (SS-B) antibodies are found in Sjögren syndrome, although this syndrome and antibodies against Ro (SS-A) are most commonly seen as a part of SLE. In addition, anti-histone antibodies may be seen in SLE and in drug-induced lupus. These two diagnoses may be distinguished by the presence of antibodies to specific histones. Finally, a positive ANA is essentially never found in systemic-onset juvenile idiopathic arthritis (Still disease).
Antinuclear Antibody Subtypes in Juvenile Systemic Connective Tissue Disease
Active SLE | MCTD | SSc | CREST | Primary Sjögren | JIA (Poly) | |
---|---|---|---|---|---|---|
ANA | 99% | 100% | 70%–90% | 60%–90% | >70% | 40%–50% |
Anti-native DNA | 60% | Neg | Neg | Neg | Neg | Neg |
Anti-Sm | 30% | Neg | Neg | Neg | Neg | Neg |
Anti-RNP | 30% | >95% titer >1:10,000 | Common (low titer) | Neg (low titer) | Rare | Rare |
Anti-centromere | Rare | Rare | 10%–15% | 60%–90% | Neg | Neg |
Anti-Ro (SS-A) | 30% | Rare | Rare | Neg | 70% | Rare |
Anti-La (SS-B) | 15% | Rare | Rare | Neg | 60% | Rare |
ANA, antinuclear antibody; anti-RNP, anti-ribonucleoprotein; anti-Sm, anti-Smith antibody; CREST, calcinosis, Raynaud’s phenomenon, esophageal dysmotility, sclerodactyly, telangiectasias; JIA, juvenile idiopathic arthritis; MCTD, mixed connective tissue disease; SLE, systemic lupus erythematosus; SSc, systemic sclerosis/scleroderma.