BACKGROUND: Antibodies for double-stranded DNA (anti-dsDNA) and chromatin represent specific markers of systemic lupus erythematosus (SLE). AIMS: (1) To evaluate the analytical performance of a multiplexed bead assay (BioPlex 2200) for the simultaneous detection of anti-dsDNA and anti-chromatin antibodies, (2) to compare the results for anti-dsDNA with those obtained using Farr assay, and (3) to analyze the clinical relevance of these antibodies when applied to the follow-up of SLE patients with active nephritis. PATIENTS AND METHODS: Hundred and five clinically characterized SLE patients and 96 healthy blood donors sera were analyzed by BioPlex 2200. RESULTS: Prevalence of these antibodies was significantly higher (p < 0.0001) in SLE patients than in controls (68 and 70% for anti-dsDNA and anti-chromatin, vs. 1% for both anti-dsDNA and anti-chromatin, respectively). If you consider a sample positive if either anti-dsDNA and/or anti-chromatin is positive, then the prevalence of these antibodies reached 78% (82/105) in SLE patients. For anti-dsDNA measurements, the kappa coefficient was 0.59 between BioPlex 2200 and Farr assay. Comparison between SLE patients with and without nephritis in a follow-up study showed that patients with active nephritis were associated with an increase of anti-dsDNA and anti-chromatin levels and a reduction of CH50, whereas no variation of antibody levels was observed in SLE patients without nephritis. CONCLUSION: Our results demonstrated a benefit of simultaneously measuring anti-dsDNA and anti-chromatin in SLE patients. The BioPlex 2200 achieved good analytical performances and proved to be a useful method for monitoring and diagnosing SLE.
BACKGROUND: Antibodies for double-stranded DNA (anti-dsDNA) and chromatin represent specific markers of systemic lupus erythematosus (SLE). AIMS: (1) To evaluate the analytical performance of a multiplexed bead assay (BioPlex 2200) for the simultaneous detection of anti-dsDNA and anti-chromatin antibodies, (2) to compare the results for anti-dsDNA with those obtained using Farr assay, and (3) to analyze the clinical relevance of these antibodies when applied to the follow-up of SLEpatients with active nephritis. PATIENTS AND METHODS: Hundred and five clinically characterized SLEpatients and 96 healthy blood donors sera were analyzed by BioPlex 2200. RESULTS: Prevalence of these antibodies was significantly higher (p < 0.0001) in SLEpatients than in controls (68 and 70% for anti-dsDNA and anti-chromatin, vs. 1% for both anti-dsDNA and anti-chromatin, respectively). If you consider a sample positive if either anti-dsDNA and/or anti-chromatin is positive, then the prevalence of these antibodies reached 78% (82/105) in SLEpatients. For anti-dsDNA measurements, the kappa coefficient was 0.59 between BioPlex 2200 and Farr assay. Comparison between SLEpatients with and without nephritis in a follow-up study showed that patients with active nephritis were associated with an increase of anti-dsDNA and anti-chromatin levels and a reduction of CH50, whereas no variation of antibody levels was observed in SLEpatients without nephritis. CONCLUSION: Our results demonstrated a benefit of simultaneously measuring anti-dsDNA and anti-chromatin in SLEpatients. The BioPlex 2200 achieved good analytical performances and proved to be a useful method for monitoring and diagnosing SLE.
Authors: Benjamin F Bruner; Joel M Guthridge; Rufei Lu; Gabriel Vidal; Jennifer A Kelly; Julie M Robertson; Diane L Kamen; Gary S Gilkeson; Barbara R Neas; Morris Reichlin; R Hal Scofield; John B Harley; Judith A James Journal: Arthritis Rheum Date: 2012-11
Authors: Rufei Lu; Julie M Robertson; Benjamin F Bruner; Joel M Guthridge; Barbara R Neas; Swapan K Nath; Jennifer A Kelly; Kathy L Moser Sivils; Eliza F Chakravarty; Diane L Kamen; Gary S Gilkeson; Daniel J Wallace; Michael H Weisman; R Hal Scofield; John B Harley; Judith A James Journal: Autoimmune Dis Date: 2012-09-04