Dense fine speckled indirect immunofluorescence pattern in an Australian population

Area of Science:

• Immunology
• Autoimmunity
• Clinical Diagnostics

Background:

• The dense fine speckled (DFS) antinuclear antibody (ANA) pattern is gaining attention in diagnostics.
• While not typically linked to systemic autoimmune rheumatic disorders (SARD), DFS has been observed in other inflammatory conditions and in healthy individuals.

Purpose of the Study:

• To determine the frequency of the DFS pattern in an Australian population using indirect immunofluorescence (IIF).
• To assess the association between the DFS pattern and various laboratory autoimmune markers.

Main Methods:

• Retrospective review of ANA tests performed by IIF between July 2012 and June 2014.
• Analysis of DFS-positive samples for concurrent testing of extractable nuclear antigens (ENA), anti-dsDNA, rheumatoid factor (RF), anti-citrullinated protein antibodies (CCP), and anti-phospholipid antibodies.

Main Results:

• The DFS pattern was identified in 5.7% of ANA-positive patients among 181,819 tested.
• Low frequencies of SARD-associated markers were observed: 1.8% for ENA, 0.7% for anti-dsDNA (>9 IU/mL), 6.3% for RF, 4.1% for anti-CCP, and 2 samples for anti-phospholipid antibodies.

Conclusions:

• The DFS pattern, detected by IIF, shows infrequent association with autoimmune markers of SARD in the Australian population.
• Findings align with international studies, suggesting DFS is not a strong indicator for SARD.