title: Anti-dsDNA antibodies in systemic lupus erythematosus: A combination of two quantitative methods and the ANA pattern is the most efficient strategy of detection.
abstract: Several methods have been used to measure anti-double-stranded DNA auto-antibody (anti-dsDNA). Our aim was to determine the most efficient strategy to test anti-dsDNA in systemic lupus erythematosus (SLE). In this study, anti-dsDNA and anti-nuclear antibody (ANA) tests were requested for 644 patients. Anti-dsDNA was tested by RIA, ELISA and CLIA in all patients. The results indicated that 78 patients had a positive anti-dsDNA test according to at least one of the methods. After a 3-year follow-up period only 26 patients were diagnosed with SLE. We evaluated each method and combination of methods. Specificity and positive predictive value (PPV) increased with the number of assay methods used (p=0.002 for trend), and PPV was 100% in patients whose results were positive by all three anti-dsDNA assay methods. The proportion of anti-dsDNA-positive patients who had SLE was highest (82%; p b 0.001) among those with a homogeneous pattern of ANA staining, followed by those with a speckled pattern. In ANA positive patients, when only RIA was considered, 59% of anti-dsDNA-positive patients had SLE, but when RIA and CLIA were both considered, all patients with positive results on both tests had SLE. The combination of RIA+CLIA in patients with homogeneous and speckled ANA staining showed a similar cost and higher sensitivity than RIA alone in ANA positive patients (p b 0.001). We conclude that the most efficient strategy was to combine simultaneously two quantitative and sensitive methods but only in patients with a homogeneous or speckled pattern of ANA staining. This approach maximized specificity and PPV, and reduced costs.
authors.affiliation: Immunology Unit, Nuestra Señora de Candelaria University Hospital, Santa Cruz de Tenerife, Spain; Research Unit, Nuestra Señora de Candelaria University Hospital, Santa Cruz de Tenerife, Spain.
authors.forename: Delia
authors.initials: D
authors.lastname: Almeida González
authors.affiliation: Rheumatology Section, Nuestra Señora de Candelaria University Hospital, Santa Cruz de Tenerife, Spain.
authors.forename: Alfredo
authors.initials: A
authors.lastname: Roces Varela
authors.affiliation: Research Unit, Nuestra Señora de Candelaria University Hospital, Santa Cruz de Tenerife, Spain.
authors.forename: Itahisa
authors.initials: I
authors.lastname: Marcelino Rodríguez
authors.affiliation: Immunology Unit, Nuestra Señora de Candelaria University Hospital, Santa Cruz de Tenerife, Spain.
authors.forename: Alexander
authors.initials: A
authors.lastname: González Vera
authors.affiliation: Rheumatology Section, Nuestra Señora de Candelaria University Hospital, Santa Cruz de Tenerife, Spain.
authors.forename: Mónica
authors.initials: M
authors.lastname: Delgado Sánchez
authors.affiliation: Rheumatology Section, Nuestra Señora de Candelaria University Hospital, Santa Cruz de Tenerife, Spain.
authors.forename: Antonio
authors.initials: A
authors.lastname: Aznar Esquivel
authors.affiliation: Immunology Unit, Nuestra Señora de Candelaria University Hospital, Santa Cruz de Tenerife, Spain.
authors.forename: Carlos
authors.initials: C
authors.lastname: Casañas Rodríguez
authors.affiliation: Research Unit, Nuestra Señora de Candelaria University Hospital, Santa Cruz de Tenerife, Spain; University of La Laguna, La Laguna, Spain. Electronic address: acableo@gobiernodecanarias.org.
authors.forename: Antonio
authors.initials: A
authors.lastname: Cabrera de León
mesh_terms: D000974:Antibodies, Antinuclear / Q000097:blood*; D001323:Autoantibodies / Q000097:blood*; D004247:DNA; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000097:blood* / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D012680:Sensitivity and Specificity
chemical_list: D000974:Antibodies, Antinuclear; D001323:Autoantibodies; D004247:DNA
keywords: Anti-double stranded DNA antibodies (anti-dsDNA); Anti-nuclear antibodies (ANA); Efficiency; Screening; Systemic lupus erythematosus