Prevalence of anti-DFS70 antibodies in patients with and without systemic autoimmune rheumatic diseases

• Published in: Clinical and experimental rheumatology Vol. 36; no. 1; pp. 121 - 126
• Main Authors: Shovman, Ora, Gilburd, Boris, Chayat, Chen, Amital, Howard, Langevitz, Pnina, Watad, Abdulla, Guy, Adi, Perez, Dolores, Azoulay, Danielle, Blank, Miri, Segal, Yael, Bentow, Chelsea, Mahler, Michael, Shoenfeld, Yehuda
• Format: Journal Article
• Language: English
• Published: Italy 01.01.2018
• Subjects: Adaptor Proteins, Signal Transducing - immunology; Antibodies, Antinuclear - blood; Autoimmunity; Biomarkers - blood; Case-Control Studies; Fluorescent Antibody Technique, Indirect; Humans; Immunoassay; Immunosorbent Techniques; Luminescent Measurements; Predictive Value of Tests; Reproducibility of Results; Rheumatic Diseases - blood; Rheumatic Diseases - diagnosis; Rheumatic Diseases - epidemiology; Rheumatic Diseases - immunology; Seroepidemiologic Studies; Transcription Factors - immunology
• ISSN: 0392-856X

Autoantibodies to the dense fine speckled 70 (DFS70) antigen are common among antinuclear antibodies (ANA) positive healthy individuals (HI). We assessed the prevalence of anti-DFS70 antibodies in patients with and without ANA-associated rheumatic diseases (AARDs) by two methods: chemiluminescent immunoassay (CIA) and an indirect immunofluorescence (IIF) assay based on immunoadsorption for DFS70. Fifty-one ANA-positive sera samples from patients with confirmed clinical diagnosis of AARD, 92 samples from HI and 85 samples submitted to a reference laboratory for routine ANA testing were evaluated for the presence of anti-DFS70 antibodies. The samples were evaluated by QUANTA Flash DFS70 CIA using BIO-FLASH instrument and by NOVA Lite selected HEp-2 kit on NOVA View - an automated IIF system. Sera with DFS positive pattern were pre-absorbed with highly purified human DFS70 antigen, and then tested again. Twenty-four samples (10.5%) tested by QUANTA Flash DFS70 CIA were positive for anti-DFS70 antibodies. The prevalence of monospecific anti-DFS70 antibodies was significantly higher in healthy subjects than in patients with AARDs (10.9% vs. 1.9%, p=0.02). The frequency of anti-DFS70 antibodies in samples submitted for routine ANA testing was 15.2%. A very good agreement was found between CIA and the DFS pattern identified by the automated HEp-2 IIF (kappa=0.97). In 80% of the samples obtained from patients without AARDs, immunoadsorption effectively inhibited the anti-DFS70 antibodies. The data confirm that mono-specific anti-DFS70 antibodies are a strong discriminator between ANA positive HI and AARD patients, and their evaluation should be included in ANA testing algorithms.