title: Measurement of anti-DNA antibodies by ELISA: a comparative study with Crithidia and a Farr assay.
abstract: One hundred and twenty six sera from 116 patients with systemic lupus erythematosus (SLE) and from 51 control patients were assayed for the presence of anti-DNA antibodies, using a commercial enzyme linked immunosorbent assay (ELISA). Fifty three sera (42%) from SLE patients were positive and a further 13 sera (10%) fell in the 'equivocal' positive range. Three control sera were positive. In a standard 14C DNA Farr assay, 67 sera (53%) from SLE patients were positive. One control serum was weakly positive. There was a good linear correlation between absorption in the ELISA and the 14C DNA binding result (r = 0.73). Results in the ELISA and Farr assays were concordant in 96 of the 126 SLE sera, and 47 of 51 control sera. Sequential sera from a further 6 patients with fluctuating clinical activity of SLE showed similar patterns of change of anti-DNA antibodies in both assays. The ELISA was more sensitive than the Crithidia luciliae immunofluorescence assay which detected 44 positive sera (35%) in the SLE group. These results suggest that this ELISA assay may be a useful alternative to the Crithidia assay or an effective screen prior to testing in the more technically difficult and time consuming Farr assay for the measurement of anti-DNA antibodies.
authors.affiliation: Department of Medicine, Monash University, Prince Henry's Hospital, Melbourne.
authors.forename: P G
authors.initials: PG
authors.lastname: Tipping
authors.forename: R C
authors.initials: RC
authors.lastname: Buchanan
authors.forename: A G
authors.initials: AG
authors.lastname: Riglar
authors.forename: W J
authors.initials: WJ
authors.lastname: Dimech
authors.forename: G O
authors.initials: GO
authors.lastname: Littlejohn
authors.forename: S R
authors.initials: SR
authors.lastname: Holdsworth
mesh_terms: D000818:Animals; D000974:Antibodies, Antinuclear / Q000032:analysis*; D003421:Crithidia / Q000276:immunology; D004247:DNA / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D008137:Longitudinal Studies; D008180:Lupus Erythematosus, Systemic / Q000276:immunology; D012680:Sensitivity and Specificity
chemical_list: D000974:Antibodies, Antinuclear; D004247:DNA