Dense fine speckled antinuclear antibody patterns: Clinical correlations and implications.

Background/purpose: The significance of Dense Fine Speckled (DFS) pattern Anti-nuclear antibodies (ANA) by indirect mmunofluorescence (IIF) is unclear in the existing research. We aimed to investigate associations between positive ANA with DFS pattern and multiple autoimmune and rheumatic conditions.

Methods: This retrospective study analyzed datasets from patients tested for ANA between August 2017 and August 2019. Comparisons were made between diagnostic categories and diseases for patients with negative ANA, positive ANA (any pattern), and positive ANA with DFS pattern. Relative risk (RR) was calculated for diagnostic categories and individual diseases.

Results: Of 13,845 ANA results, 65.8% were negative and 34.2% were positive, including 4.6% with DFS pattern. Among ANA positive DFS pattern patients, 10.6% had inflammatory arthritis, 20.6% had fibromyalgia/chronic pain syndrome/chronic fatigue, 13.3% had SARD and only 2.2% had atopic disorder. Comparing ANA positive other patterns and DFS pattern, specific diagnoses like seropositive RA, SLE, SSc, and UCTD were lower among ANA positive DFS pattern. Similarly, diagnoses of Raynaud's with SSc or UCTD were lower in DFS pattern patients compared to ANA positive with other patterns. The rate of other diagnoses including seronegative RA, IIM, SS, autoimmune thyroid disorder, and autoimmune hepatitis did not differ between other patterns and DFS pattern.

Conclusion: The presence of DFS pattern cannot indiscriminately exclude the presence of SARD or rheumatic disease, as diagnoses including seronegative RA, IIM, SS, autoimmune thyroid disorder, or autoimmune hepatitis did not differ among ANA positive with other patterns and DFS pattern.