The significance of dense fine speckled pattern in antinuclear antibody‐associated rheumatic disease and coexisting autoantibodies: A propensity score‐matched cohort study

Aim To investigate the relationship between the prevalence of antinuclear antibody (ANA) ‐associated rheumatic diseases (AARD) and the presence of dense fine speckled (DFS) and homogeneous patterns in ANA tests. Methods This retrospective study enrolled adult patients with either a DFS or homogeneous pattern in their ANA test. A mixed pattern was defined as the presence of more than one pattern reported in the test. The presence of anti‐DFS70 antibodies and other common autoantibodies were detected using EUROLINE ANA Profile 23. A 1:2 propensity score matching was applied to control for demographic and other interfering factors. Results A total of 59 patients with a DFS pattern were enrolled and compared with a matched homogeneous group. The DFS group had a significantly lower prevalence of AARD (3.4% vs. 16.9%, p = .008) and the subgroup with anti‐DFS70 antibodies showed an even lower prevalence (2% vs. 20%, p = .002). Among the 33 patients with monospecific anti‐DFS70 antibodies, five had a mixed pattern, and all patients with common autoantibodies had an isolated DFS pattern. Conclusions The findings of this study suggest that patients with a DFS pattern in their ANA test may have a lower prevalence of AARD compared with those with a homogeneous pattern. However, an isolated DFS pattern in ANA testing does not necessarily indicate the presence of monospecific anti‐DFS70 antibodies or AARD. Confirmatory testing for the monospecific anti‐DFS70 antibody is mandatory to exclude AARD.