Laboratory Tests for a Patient with High ANA Showing Nucleolar and Centromere Patterns
For a patient with very high ANA titers showing both nucleolar and centromere patterns, comprehensive autoantibody testing should include anti-centromere antibodies, anti-Scl-70, anti-RNA polymerase III, and other systemic sclerosis-specific antibodies, along with liver autoimmune serology and cancer screening due to the increased risk of malignancy associated with nucleolar pattern.
Initial Evaluation Based on ANA Pattern
The presence of both nucleolar and centromere patterns on ANA testing requires targeted follow-up testing based on their clinical associations:
Centromere Pattern
- Strongly associated with limited cutaneous systemic sclerosis (formerly CREST syndrome) 1, 2
- Testing should include specific anti-centromere antibodies (CENP-A, B, C, F) 1
- This pattern is highly specific for systemic sclerosis, particularly the limited cutaneous variant 2
Nucleolar Pattern
- Associated with systemic sclerosis, Raynaud's phenomenon, inflammatory myopathies, and overlap syndromes 1
- Significantly associated with increased risk of malignancy (RR 1.5,95% CI 1.03-2.3) 3
- Requires testing for specific nucleolar antigens including:
- PM/Scl (polymyositis/scleroderma)
- RNA polymerase I, II, III
- U3-RNP (fibrillarin)
- To/Th
- B23 phosphoprotein/numatrin 1
Recommended Laboratory Tests
1. Systemic Sclerosis-Specific Antibodies
- Anti-centromere antibodies (CENP-A, B, C, F) 1
- Anti-Scl-70 (topoisomerase I) - associated with diffuse systemic sclerosis and 15% risk of cancer 3
- Anti-RNA polymerase III - associated with diffuse systemic sclerosis and 14% risk of cancer 3
- Anti-fibrillarin (U3-RNP) - associated with nucleolar (clumpy) pattern 1
- Anti-PM/Scl - associated with overlap syndrome and Raynaud's phenomenon 4
2. Liver Autoimmune Serology
- Anti-mitochondrial antibodies (AMA) - to rule out primary biliary cirrhosis 1
- Anti-smooth muscle antibodies (SMA) - for autoimmune hepatitis type 1 1
- Anti-liver/kidney microsomal antibody type 1 (anti-LKM-1) - for autoimmune hepatitis type 2 1
- Anti-soluble liver antigen/liver pancreas antibody (SLA/LP) 1
3. Additional Testing Based on Clinical Suspicion
- If SLE is suspected: anti-dsDNA antibodies, anti-Smith, anti-RNP, anti-SSA/Ro, anti-SSB/La 1
- If inflammatory myopathy is suspected: anti-Jo-1 and other tRNA synthetases 1
- If overlap syndrome is suspected: comprehensive ENA panel 1
4. Cancer Screening
- Consider age-appropriate cancer screening due to increased malignancy risk associated with nucleolar ANA pattern 3, 4
- Particularly important if anti-Scl-70 or anti-RNA polymerase III antibodies are positive 3
Important Considerations
Interpretation of Results
- ANA titers should be reported with patterns and highest dilution showing reactivity 1
- Clinically significant positivity starts at 1:40 dilution in adults, but may be lower in children 1
- Specific antibody testing should be performed regardless of ANA titer when clinical suspicion is high 1
Technical Considerations
- HEp-2 cells are the preferred substrate for ANA detection as they better visualize nucleolar and centromere patterns 1
- The laboratory should report any level of positivity from 1:10, with interpretation based on clinical context and patient age 1
- False negatives can occur with automated methods; IIFA (indirect immunofluorescence assay) remains the reference standard 1
Pitfalls to Avoid
- Do not rely solely on ANA screening without specific autoantibody testing 1
- Avoid misinterpreting low-titer ANA positivity in healthy individuals (up to 54.3% of healthy individuals may have positive ANA at low titers) 5
- Remember that different methods for ANA detection may yield different results; method should always be specified 1
- Be aware that anti-LKM-1 and AMA both stain renal tubules and are frequently confused 1
By following this comprehensive approach to autoantibody testing in a patient with both nucleolar and centromere patterns, you can effectively narrow the differential diagnosis and guide appropriate management decisions.