Evaluation of Positive Cases for Dense Fine Speckled (DFS) Immunofluorescence Pattern and Anti-DFS70 Antibodies

The detection of anti-nuclear antibodies (ANA) is crucial in diagnosing systemic autoimmune rheumatic diseases (SARDs). The Dense Fine Speckled (DFS) nuclear pattern is one of the most common indirect immunofluorescence (IIF) patterns detected during routine ANA screening in patients with various clinical conditions. The aim of this study was to analyze the data of patients who were positive for DFS/antiDFS in our patient population and to show the possible clinical relationship.

In this retrospective study, 7406 patient serum samples sent to our laboratory for routine ANA screening between May 2022-2023 were evaluated for the presence of anti-DFS.

In a group of patients referred for routine ANA screening using the indirect immunofluorescence method, the frequency of DFS pattern was found to be 4.55% (337/7406), with ANA positivity detected at a rate of 25.68% (1902/7406). Out of 221 patients with DFS pattern, 181 tested positive for anti-DFS antibodies in both the IIF-ANA and immunoblot (IB) tests. Additionally, 11 of these patients tested positive for other antibodies against different extractable nuclear antigens (anti-ENAs). Conversely, only seven out of the 40 patients who tested negative for anti-DFS antibodies showed positive results for other anti-ENAs.

The DFS pattern is often positive in individuals. In patients exhibiting this pattern, anti-DFS70 antibody may be detected alone or in combination with SARD-associated autoantibodies. Therefore, we propose that in this patient cohort, it would be more prudent to screen for additional concomitant autoantibodies with anti-ENA rather than confirming isolated anti-DFS.