The Role of Anti-DFS70 in the Diagnosis of Systemic Autoimmune Rheumatic Diseases

The diagnosis of systemic autoimmune rheumatic disease (SARD) or its exclusion is carried out taking into account the results of immunological studies, primarily antinuclear antibodies (ANA) and specific autoantibodies. Often, during ANA analysis via indirect immunofluorescence reaction on cellular and tissue substrates, a dense fine speckled 70 (DFS70) fluorescence pattern is observed. Studies on the diagnostic significance of antibodies to anti-DFS70 allow for optimizing the stepwise diagnosis of SARD. Currently, a two-step strategy for laboratory diagnostic investigation is recommended: in the first step, ANA screening is performed, and in the second step, patients with positive results undergo confirmatory tests to detect specific antibodies against individual nuclear antigens. The detection of anti-DFS70 in ANA-seropositive patients without clinical and/or other specific serological markers characteristic of a particular disease within the SARD group may be considered a negative prognostic marker. Also, in the process of decision making in clinical practice, we should remember that anti-DFS70 can be found in the blood of patients with a different, non-SARD pathology and that most people showing anti-DFS70 are healthy individuals.