Antinuclear Antibody Patterns and Clinical Significance

Standard ANA Patterns and Their Significance

The American College of Rheumatology recommends that homogeneous patterns are associated with antibodies to dsDNA, histones, chromatin/nucleosomes, and HMG proteins, commonly seen in Systemic Lupus Erythematosus (SLE), drug-induced lupus, and juvenile idiopathic arthritis 1
The European League Against Rheumatism notes that coarse speckled patterns are associated with U1-SnRNP, U2-6 snRNP (Sm), nuclear matrix antibodies, seen in Mixed Connective Tissue Disease (MCTD), SLE, Raynaud's, and systemic sclerosis 1
Fine speckled patterns are associated with SSA/Ro, SSB/La, Topo-1 antibodies, common in SLE, Sjögren's syndrome, and systemic sclerosis, according to the American College of Rheumatology 1, 3
Centromere patterns are associated with CENP-A, B, C, F antibodies, seen in limited systemic sclerosis and Raynaud's phenomenon, as stated by the European League Against Rheumatism 1
Nucleolar patterns are associated with PM/Scl, RNA-polymerase antibodies, seen in systemic sclerosis, Raynaud's, and inflammatory myopathies, according to the American College of Rheumatology 1
Nuclear dot patterns are associated with Sp100 and PML bodies, seen in primary biliary cirrhosis and autoimmune hepatitis, as noted by the European Association for the Study of the Liver 4
Diffuse cytoplasmic patterns are associated with ribosomal P proteins, Jo-1, and other tRNA synthetases, according to the American College of Rheumatology 2

The International Consensus on ANA Patterns recommends that both pattern and titer should always be reported for ANA results, with a strength of evidence level of high, as stated by the American College of Rheumatology 3
Indirect immunofluorescence assay (IIFA) on HEp-2 cells remains the reference method for ANA detection, with a sensitivity of 95.8% and specificity of 86.2%, according to the European League Against Rheumatism 5

A screening dilution of 1:160 on HEp-2 substrates is generally suitable for detecting clinically significant ANA, with a high level of evidence, as recommended by the American College of Rheumatology 3
Higher titers (>1:160) have greater clinical specificity (86.2%) while maintaining appropriate sensitivity (95.8%) for systemic autoimmune rheumatic diseases, according to the European League Against Rheumatism 3
Follow-up testing should be pattern-specific, with anti-dsDNA testing recommended for homogeneous patterns, and testing for specific extractable nuclear antigens (ENA) indicated for speckled patterns, as stated by the American College of Rheumatology 3, 6

ANA testing is primarily intended for diagnostic purposes, not for monitoring disease progression, with a low level of evidence, as noted by the European League Against Rheumatism 5
Up to 25% of sera from apparently healthy individuals can be ANA positive, depending on demographics and test variables, according to the American College of Rheumatology 7
Different laboratories may use different methods and cutoffs, affecting result interpretation, with a moderate level of evidence, as stated by the European League Against Rheumatism 3
In cases of high clinical suspicion, physicians should request determination of specific antibodies regardless of the ANA result, as some autoantibodies may be present in ANA-negative patients, with a high level of evidence, as recommended by the American College of Rheumatology 2, 3