The Prevalence of Anti-DFS۷۰ Antibodies in SLE and Non-SLE Patients

Background: The presence of anti-DFS۷۰ antibodies was considered by some rheumatologists as a tool to help exclude the diagnosis of systemic autoimmune rheumatic diseases (SARDs) such as systemic lupus erythematosus (SLE). However, several studies reported the controversial result. The golden standard for anti-DFS۷۰ antibody detection is indirect immunofluorescence (IIF) assay. Recently, ELISA method has been developed for the anti-DFS۷۰ detection.Objective: We aimed to investigate the presence of anti-DFS۷۰ antibodies in SLE and non-SLE patients using IIF assay and ELISA.Methods: We evaluated ۴۵ SLE patients who fulfilled the Systemic Lupus International Collaborating Clinics (SLICC) classification criteria, SLEDAI score >۵; ۱۵ patients with atopic dermatitis (AD) with IgE >۲۰۰ IU/ml, and ۳۰ healthy subject individuals. Anti-DFS۷۰ antibodies were measured by ELISA and IIF assay (ANA-DFS۷۰ Cytobeads). Differences in the anti-DFS۷۰ prevalence in SLE and non-SLE patients were analysed using a chi-square test. The sensitivity, and specificity of ELISA were calculated by McNemar’s test.Results: The presence of anti-DFS۷۰ antibodies measured by IIF assay was found in ۱۱.۱% of SLE and ۴.۴% of non-SLE patients (p-value ۰.۴۳۴), while anti-DFS۷۰ measured by ELISA was found in ۱۷.۷% of SLE and ۶.۶% of non-SLE patients (p-value ۰.۱۹۷). There was no significant difference in detecting anti-DFS۷۰ of the two methods (p.۰.۰۵).  The ELISA has a sensitivity of ۸۵.۷% and a specificity of ۹۴% for anti-DFS۷۰ detection.Conclusion: Anti-DFS۷۰ was detected more frequently in SLE rather than in non-SLE patients measured using both ELISA and IIF. There is good agreement between ELISA and IIF assay for the anti-DFS۷۰ detection.